Valence
“In psychology, valence refers to the intrinsic attractiveness (positive valence) or aversiveness (negative valence) of an event, object, or stimulus. Valence is a core component in emotion theories and plays a key role in aesthetic judgment, affective forecasting, and decision-making. In the context of perception and aesthetics, valence often underpins preference formation and emotional responses to visual stimuli.”
Value
“Relative lightness or darkness. A fundamental component of visual perception and representation.”
Value Scale
“A sequential arrangement of values representing incremental steps from light to dark, typically used to develop sensitivity to relative luminance and to calibrate perceptual-motor mapping in representational drawing and painting. Within the Waichulis Curriculum, value scales are not employed as static templates to copy, but as tools for perceptual refinement—training the artist to discriminate, produce, and transition between values with increasing precision.
Exercises like the Full Value Pressure Scales and Gradation Blocks rely on value scales to isolate the effects of applied pressure, material saturation, and surface tooth interaction. These exercises strengthen the artist’s ability to detect and reproduce nuanced value shifts, a foundational skill for achieving volumetric representation and effective light-form interaction.
Crucially, value scales also play a role in overcoming perceptual constancies such as lightness constancy, by grounding visual judgments in actual stimulus conditions rather than conceptual approximations. As such, value scale training supports the broader goals of perceptual calibration, edge control, and spatial logic throughout the curriculum.”
Vanishing Point
“A point on the horizon line where parallel lines in three-dimensional space appear to converge in a two-dimensional depiction due to the effects of linear perspective. In one-point perspective, all lines perpendicular to the picture plane converge to a single vanishing point. In two- or three-point systems, additional vanishing points account for width, height, and depth recession. These constructions reflect perceptual mechanisms, such as size constancy and depth cues, and were mathematically systematized during the Renaissance by figures like Brunelleschi and Alberti.”
Vanitas
“A subgenre of still life painting that emerged in 16th- and 17th-century Northern Europe—particularly in Dutch and Flemish art—characterized by symbolic imagery designed to illustrate the futility of earthly pleasures and the inevitability of death. The term comes from the Latin vanitas, meaning ’emptines’ or ‘futility’, and is most closely associated with the biblical phrase Vanitas vanitatum, omnia vanitas (‘Vanity of vanities, all is vanity’) from Ecclesiastes.
Unlike the more direct symbolic reminders found in memento mori, vanitas compositions often contrast material abundance—such as books, coins, musical instruments, fine textiles, mirrors, and jewelry—with symbols of decay and mortality like skulls, rotting fruit, wilting flowers, hourglasses, and extinguished candles. The tension between opulence and impermanence conveys a moralizing message about the transient nature of beauty, knowledge, wealth, and status.
While highly codified in its original historical context, the vanitas framework offers representational artists a powerful structure for embedding symbolic narrative, visual irony, or existential commentary within still life or figural works. Understanding vanitas allows for more intentional compositional choices where objects are not merely described, but function symbolically within a thematic or philosophical framework.
Vanitas imagery remains relevant in contemporary realist practice, particularly when addressing themes of time, entropy, and meaning, and can be used to reinforce visual tension, contrast, and narrative subtext.”
Vellum
“A historically significant substrate originating from animal skin—typically calf, goat, or sheep—vellum is a dense, durable, and slightly translucent surface used in both manuscript production and fine art. Distinguished from the coarser parchment, vellum was prized in the Middle Ages for illuminated texts and delicate ink drawings. The finest grades were often made from the skins of newborn animals and finished through a process of soaking, stretching, drying, and surfacing to yield a smooth yet fibrous surface with exceptional permanence.
In modern usage, vellum refers to a synthetic or chemically treated cellulose sheet designed to emulate the translucent properties of animal vellum. Unlike tracing paper, modern vellum is generally thicker, smoother, and more dimensionally stable, making it ideal for inked illustrations, architectural drafting, and mixed media applications. It supports a range of dry media and resists warping or cockling under moderate wet applications, although it remains best suited for linear work.
The composition of traditional vellum and modern vellum differs. Traditional Vellum: Calfskin (or other animal skin), prepared through mechanical and chemical surfacing. Modern Vellum: Cotton or wood pulp cellulose treated for translucency and durability; often acid-free and archival. Both varied in common usage as well. Historical: Manuscript illumination, miniature painting, calligraphy. Modern: Technical drawing, ink rendering, architectural plans, overlays.
Vellum’s interaction with media varies depending on its composition. Traditional vellum has a fibrous tooth that can accept ink, graphite, or paint when properly sized. Modern vellum, while smoother, is still receptive to graphite, pen, and technical ink but may resist heavy layering or wet blending.
Vellum is distinct from, but related to, other papers, including:
Tracing Paper: Generally lighter, more transparent, and more flexible; preferred for overlays and planning, but less durable.
Parchment: A broader term often used for less refined animal skins with more texture and irregularity.
Drafting Film (e.g., Mylar): A synthetic plastic alternative with greater rigidity and erasure resistance, often confused with vellum but fundamentally different in behavior and surface chemistry.
Vellum has seemingly become less common in studio drawing practices today due to availability and cost, but it remains an important reference point in the history of substrates. Its modern counterparts, however, are still employed in design, illustration, and conservation workflows where stability, translucency, and surface resilience are required.”
Verdaccio
“A greenish-gray or olive-hued underpainting technique used in traditional tempera and fresco painting, primarily to develop an initial value structure before subsequent color application. It was especially prevalent in Renaissance painting as a means of achieving specific flesh tones by juxtaposing the greenish-gray with applications of red or ‘warm’ glazes.
Verdaccio was extensively used in Italian Renaissance fresco painting, most notably by Giotto, Masaccio, and Leonardo da Vinci. The technique was key to early sfumato (painting technique characterized by the soft, gradual blending of tones and colors to create subtle transitions between light and shadow) applications, allowing artists to modulate tonal transitions in a way that mimicked atmospheric light effects. The greenish undertone of verdaccio was effective in neutralizing overly warm flesh colors, producing a more naturalistic appearance when final layers of pinks, reds, and earth tones were applied. It was a standard approach in buon fresco, where the verdaccio layer was integrated directly into the plaster. In oil painting, the concept evolved into more sophisticated underpainting methods, influencing later developments in glazing techniques.”
Veridical
“In the context of perception and cognition, veridical refers to a perceptual experience or mental representation that corresponds accurately to the actual properties of the external world. A veridical perception is one that is objectively correct or truth-tracking—that is, it reflects the world as it really is, independent of the perceiver’s interpretation or internal states.
However, under contemporary empirical models (e.g., Purves et al. 2001; Hoffman 2015), veridicality is challenged as an ideal: perception is not designed to reflect objective reality, but to guide adaptive behavior based on successful past interactions. Thus, most perceptual experiences are useful, but not necessarily veridical. In representational art, veridicality would imply a depiction that maps directly onto measurable external reality—yet the Waichulis Curriculum emphasizes that all image-making must mediate perception, and is thus inherently non-veridical.”
Verisimilitude
“The appearance of being true, real, or lifelike—without requiring actual truth or objective correspondence. In art and literature, it denotes the degree to which a representation plausibly resembles reality as it is perceived or understood, based on the viewer’s prior experiences, expectations, or cultural knowledge.
In visual art, verisimilitude is achieved through the orchestration of perceptual cues (e.g., light, form, texture, proportion) that simulate the look and feel of a real-world subject, even if the depiction is invented or stylized. It is the foundation of perceptual realism and illusionism, and contrasts with both abstraction and schematic representation. Verisimilitude is not about objective truth—it is about perceptual believability. A scene may be entirely imaginary and yet still exhibit a high degree of verisimilitude.
In short: Veridical = truth-accurate (objective) while Verisimilitude = truth-like (perceptual/plausible).”
Vernier Acuity
“(Also referred to as Vernier Hyperacuity) A specialized form of visual perception that allows an individual to detect extremely small misalignments or shifts between two or more elements. This ability exceeds the typical resolution limits of the human eye, enabling the detection of spatial differences that are far finer than what would be perceived by normal visual acuity. A practical example of Vernier Acuity can be seen in optometry, where it is often used in tests to measure a person’s ability to discern slight misalignments between lines or bars. For instance, in a Vernier acuity test, two short lines may be presented with one line slightly displaced horizontally or vertically, and the task is to identify the minimal shift between them. This ability is essential in fields like surgery, where precision is crucial, or in digital design, where exact alignment of elements in a layout is necessary. In these contexts, Vernier Acuity allows individuals to notice misalignments that would otherwise go unnoticed by the average observer, demonstrating a level of visual precision that goes beyond normal resolution limits.”
Vertical Palette
“A paint-mixing surface oriented perpendicularly or at a steep angle to the working support, allowing an artist to mix and access paint while maintaining head-level sightlines. This configuration contrasts with traditional flat palettes held in the hand or placed horizontally on a table.
In the Waichulis Curriculum, the vertical palette is sometimes integrated into a customized easel-mounted setup, enabling continuous visual comparison between palette mixtures and the painting surface without requiring the artist to reduce shifts in focus or posture. This alignment reduces unnecessary eye or head movement, minimizes switch costs, and promotes perceptual consistency when calibrating hue, value, and chroma.
While vertical palettes are not common in traditional studio practice, their strategic use in perceptual training offers several benefits including: direct visual adjacency between palette and canvas for immediate perceptual feedback, ergonomic alignment that reduces strain and maintains a consistent working posture, and increased support for color calibration, especially during exercises where precise ‘matches’ in optical conditions matter.
The surface of the vertical palette is typically made of white melamine, glass, or another easy-to-clean material that allows for high-contrast visibility of color mixtures. Students are advised to develop consistent palette layouts on these vertical surfaces to reduce cognitive load and improve procedural fluency.
Though unconventional, the vertical palette serves a functional role in the perceptual-motor training model of the Waichulis system, offering a controlled environment in which the visual system can more effectively gauge and adjust paint mixtures under stable contextual conditions.”
Viewfinder
“A framing device—typically a small, handheld tool with an open window—that allows an artist to isolate, crop, or select a portion of the visual field for compositional analysis or spatial calibration. Often made from matboard, cardboard, plastic, or acetate, viewfinders may feature adjustable or fixed apertures of various aspect ratios (e.g., 4:3, 16:9) to mimic the dimensions of a working surface.
While not exclusive to any single tradition, viewfinders have long been used as aids to visual composition, with origins traceable to devices like the Claude glass in the 18th century—a tinted mirror used by landscape artists to simplify and harmonize complex views. The notion of selectively framing reality can also be linked to the use of the camera obscura and early photographic practice, which influenced 19th-century framing conventions in painting.
In contemporary studio training, viewfinders serve as perceptual enhancement tools. By isolating portions of the visual environment, they reduce extraneous visual data, support comparative measurement, and encourage the artist to consider shape relationships, alignment, and negative space more critically. They are especially useful for: blocking compositional elements within a scene, establishing proportional relationships within a constrained field, and/or aiding in angle measurement, tilt assessment, or perspective alignment.
In the Waichulis Curriculum, viewfinders may be introduced to support visual-spatial reasoning. The tool can be seen as a cognitive bridge—a tool that temporarily stabilizes complex spatial input while foundational observational strategies mature. A viewfinder’s responsible use can significantly enhance early-stage accuracy without undermining long-term skill development.”
Viscosity
“A fluid’s resistance to deformation or flow under an applied force. In artistic materials—particularly paints, oils, and mediums—it describes how thick or fluid a substance is when manipulated by brush, knife, or other tools. Higher viscosity materials resist movement and tend to hold their shape; lower viscosity materials flow more readily and level out across a surface. In the context of painting, viscosity plays a pivotal role in determining:
Brush behavior: High-viscosity paints (e.g., those with added stand oil or little solvent) will retain brush marks and build texture. Low-viscosity paints (e.g., heavily thinned with solvent or medium) allow for smooth blending and flat applications.
Layering dynamics: Thicker paints can rest on top of thinner ones without mixing, supporting the fat-over-lean principle. Conversely, overly fluid underlayers can cause later layers to sink or crack.
Medium design: Oil mediums are often formulated with specific viscosities to control drying time, leveling, and adhesion. Mayer notes the use of viscosity standards—such as flow cup tests or bubble rise comparisons—to define handling qualities and formulation accuracy.
Importantly, viscosity is distinct from—but related to—plasticity, which describes a material’s ability to resist deformation until a threshold force is applied. Some artist-grade paints are both viscous and plastic, offering thick application with minimal sagging.
Artists can manipulate viscosity intentionally through additives like solvents (to decrease it), resins or bodied oils (to increase it), or mechanical means (e.g., stirring or warming). Understanding and controlling viscosity allows for more predictable application behavior, supporting consistent blending, layering, and surface finish across painting workflows.”
Visual Angle
“A measure of how large an object appears to the eye, defined by the angle (in degrees) that an object subtends (i.e., spans or occupies in the visual field as projected from the eye) at the eye’s nodal point (i.e., the optical center of the eye where incoming light rays are assumed to converge before diverging toward the retina). It is determined by both the object’s physical size and its distance from the observer. Mathematically, visual angle is the inverse tangent of the object’s height divided by its distance:
tan(α) = h / d, where α is the visual angle, h is object height, and d is distance.
This measure is crucial in understanding how the retinal image is formed, as larger angles correspond to larger images on the retina. For example, a nearby small object can cast the same retinal size (and thus visual angle) as a larger object viewed from farther away. Because of this ambiguity, the visual system cannot infer absolute size from visual angle alone—requiring additional depth cues to resolve the size-distance indeterminacy.
In representational art training, awareness of visual angle is central to understanding: foreshortening: as parts of an object recede in space, they subtend smaller visual angles and appear compressed, perspective distortion: shifts in viewpoint alter visual angles, affecting proportional relationships, and comparative measurement: artists must learn to make relative judgments based on how much of the visual field a form occupies, not its objective dimensions.
Importantly, visual angle is a proximal stimulus metric—it refers to how things project onto the eye, not how large they are in the world (the distal stimulus). This distinction underlies phenomena like size constancy, where the brain maintains a stable size percept despite changing visual angles across different viewing conditions.
Visual angle is thus foundational to both projective geometry and the perceptual strategies used in realistic drawing, where accurate rendering depends not on known size, but on observed retinal scale and relational placement.”
Visual Calibration
“The process by which an artist adjusts and refines motor behaviors to align perceptual intent with material outcome. In the Waichulis Curriculum, calibration is not framed as a correction of faulty vision, but as a strategy for managing the non-veridical nature of the visual system—acknowledging that visual perception is inherently interpretive and probabilistic, not an accurate recording of objective reality.
Because the visual system is shaped by prior experience and contextual inference, perceptual outputs are always subject to distortion, illusion, or ambiguity. Visual calibration compensates for these perceptual limitations by developing reliable procedural responses to specific perceptual cues. Through structured repetition, feedback analysis, and targeted exercises (e.g., pressure scales, shape replication, gradation patterns), learners refine the internal coordination between what they perceive and how they respond, gradually stabilizing their ability to generate consistent and intentional outcomes.
This calibration process is dynamic, context-sensitive, and ongoing—allowing the learner to adapt to variations in scale, media, surface, and task complexity. It represents a central pillar of creative fluency and is a distinguishing feature of skill acquisition in the Waichulis system: not learning to see more accurately, but learning to act more effectively in response to how one sees.”
Visual Capture
“A phenomenon where visual information dominates or overrides information from other senses, such as hearing or touch, in the perception of an event or object. This occurs when conflicting sensory inputs are present, but the brain gives more weight to visual cues, causing us to perceive the world based primarily on what we see.
A classic example of visual capture can be observed in the McGurk effect, where conflicting auditory and visual stimuli (such as a person saying one sound while their lip movements suggest another) cause the brain to combine the two inputs, often resulting in a perception of a sound that doesn’t match either the auditory or visual stimulus alone.
Another example is the rubber hand illusion, in which a person sees a rubber hand being stroked while their real hand is hidden from view. If the sensory cues from touch and vision are synchronized, the brain may ‘capture’ the visual information and create the illusion that the rubber hand is part of the body.
Visual capture highlights the dominance of vision in guiding our perceptions, often shaping how we interpret sensory information in situations where different senses provide conflicting.”
Visual Crowding Effect
“The reduced ability to distinguish objects in cluttered visual environments, impacting peripheral detail perception. This phenomenon occurs when objects are too close together, causing interference and making it harder to distinguish the target from its surroundings. It’s particularly noticeable in peripheral vision, where the ability to resolve fine details is less sharp than in central vision.
A practical example of visual crowding can be seen when trying to read small text in a crowded or cluttered environment. For instance, if you are looking at a street sign with many other signs or objects around it, the surrounding distractions might make it harder to focus on and read the words clearly, even though you would have no trouble reading the same text in an uncluttered setting.
Visual crowding is thought to arise because the visual system’s processing resources become overloaded when trying to distinguish between multiple objects that are too close to each other. It is especially challenging in conditions of reduced contrast or lower visual acuity, like when looking at objects in dim light or peripheral vision.”
Visual Information
“The structured optical input derived from light reflecting off surfaces in the environment and entering the visual system. It includes patterns of luminance, chromaticity, orientation, motion, spatial frequency, and other physical properties that can be detected and interpreted by the brain to produce perceptual experience.
However, visual information is not synonymous with objective reality. In the Waichulis Curriculum, it is understood as proximal stimulus data—raw sensory input that the visual system uses to infer meaningful outcomes based on prior experiences and context. Due to the ambiguous nature of retinal stimuli (e.g., size-distance indeterminacy, lighting variability), the brain relies on heuristic processing and empirical learning to resolve what visual input ‘means.’
In representational drawing and painting, artists learn to identify, extract, and manipulate visual information to communicate form, depth, light, texture, and spatial relationships. Exercises across both the Language of Drawing and Language of Painting emphasize isolating key informational elements such as: edge transitions (abrupt or gradual changes in value or color), cast and form shadow logic, occlusion relationships, surface curvature via gradation, and contrast-based feature boundaries.
Through calibration and refinement, students are trained to perceive and replicate these visual cues accurately—developing perceptual fluency not just in seeing, but in translating what is seen into meaningful image-making behaviors.
Ultimately, the structured optical input encountered by the visual system acts as the conditional input for perceptual construction—stimulus patterns from which the brain generates behaviorally useful percepts. In image-making, mastery over visual information refers to control over these conditions—guiding the viewer toward consistent perceptual outcomes.”
Visual Language
“The structured system of perceptual and material elements—such as value, shape, edge, chroma, orientation, and spatial organization—used to construct and communicate visual information. Like spoken or written language, visual language is governed by learned conventions, relationships, and hierarchies that allow for the effective transmission of meaning. In the Waichulis Curriculum, visual language is developed not as an expressive abstraction but as a calibrated operational framework through which artists learn to perceive, manipulate, and orchestrate visual components with intention and clarity.
The curriculum treats visual language as both a cognitive-perceptual system and a material system. On the perceptual side, learners are trained to recognize and differentiate key visual phenomena—such as contrast, form light, cast shadow, occlusion, and edge behavior—that constitute the informational backbone of representation. On the material side, students develop the motor precision and procedural fluency needed to deliver those phenomena in a deliberate, accurate, and consistent way across various media. Through hierarchical training, each component of the visual language is isolated, practiced, and integrated to promote not only technical control, but also perceptual awareness and strategic intent.
Importantly, fluency in visual language does not imply stylistic conformity or adherence to traditional models of realism. Rather, it refers to the artist’s ability to construct legible, intentional visual statements—to make choices about what to show, how to show it, and to whom, with control over how visual elements impact or influence perception and interpretation. The more fluent an artist becomes in the mechanics of visual language, the more freely they can engage in abstraction, narrative, design, or invention without sacrificing clarity or coherence.
Visual language, as cultivated in the Waichulis Curriculum, is not an artistic embellishment—it is the primary communicative medium of image-making, grounded in observation, refined through feedback, and deployed with purpose.”
Visual Literacy
“The ability to interpret, analyze, and create visual information, enabling effective communication through visual means. This competency encompasses understanding visual elements such as color, shape, tone, texture, figure-ground relationships, balance, and hierarchy, which are foundational for conveying ideas and emotions visually.
Within the Waichulis Curriculum, visual literacy is developed through structured exercises that enhance visual-spatial skills, analysis, and integration. These exercises aim to cultivate a quantifiable synthesis of visual literacy and communication skills, allowing students to interact and contribute effectively in a world increasingly dominated by visual stimuli.
Developing visual literacy is crucial for artists to create works that effectively communicate visual information to viewers, fostering a deeper understanding of visual culture and enhancing the ability to convey complex concepts through visual media.”
Visually Guided Behavior
“Actions initiated and modulated in response to visual input, wherein the visual system functions not to reconstruct reality, but to generate behaviorally successful outcomes based on prior perceptual-motor associations. It is central to both biological survival and learned skill development, forming the adaptive link between sensory input and motor output.
In the empirical framework of vision proposed by Dale Purves and colleagues, perceptual experience is shaped entirely by the history of outcomes associated with similar retinal stimuli—not by direct access to the physical properties of objects. The visual system does not decode the world as it is, but instead triggers reflexive and learned responses that have historically proven effective. As such, visual percepts are operational constructs, shaped by the success or failure of previous behaviors guided by similar inputs. Key properties of visually guided behavior include:
Feedback-driven calibration: Behaviors are refined through trial, error, and feedback, reinforcing connections between specific perceptual inputs and useful responses.
Probabilistic mapping: Given the inherent ambiguity of retinal stimuli, the brain relies on statistical associations (rather than measurements) to generate likely behavioral outputs.
Dissociation of representation and action: Successful visually guided actions may occur even in the absence of conscious perception, as demonstrated in cases of dorsal stream integrity with ventral stream damage (e.g., blindsight or optic ataxia).
In studio contexts, visually guided behavior underlies all perceptual-motor mapping—the repeated association of observed stimuli with deliberate material responses. The Waichulis Curriculum cultivates this capacity through structured exercises (e.g., Shape Replication, Form Box, Gradation Block) that repeatedly link specific visual conditions to specific motor outcomes, building a library of operational responses that are both accurate and adaptive.
This concept also provides an empirical anchor for why so-called ‘visual illusions‘ are not failures of vision, but natural outcomes of a behaviorally grounded system—one optimized not for objective accuracy, but for producing useful perceptual responses under ambiguous conditions.
Visually guided behavior thus defines the functional purpose of vision itself: not to mirror the world, but to act within it effectively.”
Visual Perception
“The ability to interpret the surrounding environment by processing information contained in visible light. This process involves detecting light through the eyes, which initiates a cascade of neural processes that can ultimately result in perceptual experiences of the world. However, perception is not a veridical reconstruction of objective reality but rather a process that generates behaviorally useful experiences based on evolutionary and statistical constraints.
According to Dale Purves’ Empirical Ranking Theory, the brain does not measure or infer absolute properties of objects but instead ranks potential perceptual outcomes based on prior visual encounters. Attributes such as luminance, color, and depth are not fixed physical properties but perceptual constructs shaped by the frequency and success of past experiences. This means that vision is inherently non-veridical, producing percepts that maximize functionality rather than accurately representing external reality.
In contrast, computational models (such as those outlined by Stephen Palmer in Vision Science, Photons to Phenomenology, and David Marr’s hierarchical processing theory) describe perception as an information-processing system that extracts structured data from retinal input using feature detection and hierarchical neural mechanisms. These models emphasize the stepwise transformation of raw sensory input into meaningful representations, assuming that perception reconstructs real-world properties through structured processing.
However, Purves’ framework challenges this assumption by demonstrating that perceptual outcomes are not objective measurements but adaptive responses shaped by prior experience. Rather than computing scene properties from first principles, the brain selects the most statistically successful percepts from past encounters—even if they do not correspond to an external physical truth.
Expanding on this non-veridical perspective, Donald Hoffman’s Interface Theory of Perception suggests that perception does not evolve to represent reality accurately but instead functions as an interface that hides objective reality and presents only information relevant to survival. Just as a computer desktop simplifies complex digital processes by displaying icons rather than raw code, perception presents simplified, species-specific constructs that maximize evolutionary fitness rather than providing an accurate depiction of the world. Hoffman’s theory further supports the idea that perception is fundamentally shaped by utility rather than truth, reinforcing the role of evolutionary pressures in shaping visual experience.
Thus, visual perception is not merely a sensory recording of the world but an adaptive, experience-driven system shaped by statistical regularities and evolutionary pressures. Whether framed through empirical, computational, or cognitive perspectives, vision remains a constructive process that transforms light into structured experiences, allowing organisms to navigate and interact with their environment effectively.”
Visual Persistence
“A phenomenon where an image continues to be perceived after the visual stimulus has been removed. Essentially, it’s the lingering effect of visual information in the brain even after the object or scene has disappeared from view. This effect can last for a brief period of time, typically fractions of a second to a few seconds.
A common example of visual persistence occurs when you see a flash of bright light, like a camera flash or a lightning strike. After the light source has disappeared, you might still ‘see’ the light or the shape of the flash for a brief moment. This is also evident in the persistence of vision phenomenon seen in motion pictures—when a series of still images is shown rapidly in sequence, the brain blends them together to create the illusion of smooth motion.
Another example is the ‘trail’ effect seen when moving a bright object quickly in front of a dark background. The movement can leave behind a faint ‘afterimage’ of the object, even though the object is no longer in its original position. This is due to the brain’s temporary storage of visual information before it fades away.
Visual persistence is a normal aspect of how our visual system processes and interprets images, helping to create a continuous and coherent perception of the world. However, it can sometimes cause distortions, particularly in situations where the stimuli are moving rapidly or rapidly changing.”
Visual Problem-Solving
“The perceptual and cognitive processes by which an observer or artist identifies, organizes, and resolves visual ambiguities or challenges to extract meaning or construct coherent representations. It encompasses a range of interpretive behaviors—from deciphering complex arrangements of form, value, and space to resolving inconsistencies between expectation and observation.
In the Waichulis Curriculum, visual problem-solving is developed through hierarchical exercises that challenge learners to detect, diagnose, and reconcile discrepancies between a stimulus and its perceptual reconstruction. Tasks like Shape Replication and the Form Box are not only exercises in execution, but platforms for building flexible, schema-based perceptual models that support ongoing adaptive refinement.
Neuroscientist V.S. Ramachandran, a key figure in the field of neuroaesthetics, proposed visual problem-solving as one of the eight laws of artistic experience. He argued that when a viewer must ‘work through’ a visual puzzle—such as ambiguous grouping, camouflaged form, or unexpected spatial relationships—the process itself is rewarding, often activating the limbic system. The delayed resolution or ‘aha’ moment becomes emotionally reinforcing, prompting sustained engagement.
Artists may deliberately engage viewers in visual problem-solving by layering information to encourage multiple interpretive passes, obscuring or abstracting elements to delay recognition, using contrast, occlusion, or unconventional grouping to create tension, or embedding metaphorical or symbolic visual structures.
Critically, visual problem-solving is not limited to the viewer’s experience—it is also a core studio behavior. Artists continually encounter spatial, structural, and material challenges in image-making, requiring iterative adjustments, predictive reasoning, and internal simulation of outcomes. As such, visual problem solving links perception, cognition, and creative fluency in both the production and reception of pictorial images.
The efficacy of an artwork may often depend not just on what is seen, but how it is discovered.“
Visual Scintillation
“A perceptual effect in which adjacent regions of an image—often differing in hue but matched in luminance—appear to shimmer, pulsate, or vibrate. This phenomenon, commonly referred to as visual scintillation, arises from the disruption in spatial localization mechanisms when the ‘what’ (ventral) and ‘where’ (dorsal) visual pathways respond differentially to a stimulus.
In conditions of equiluminance—where two different colorants share the same luminance—the ventral stream (responsible for identifying color and form) can successfully process the input, but the dorsal stream (which handles motion and spatial positioning) receives insufficient luminance contrast to accurately determine position or motion. The result is a spatial ambiguity that can cause a subtle, yet perceptually unstable, visual experience of jittering or undulating boundaries.
One of the most cited examples of this effect is Claude Monet’s Impression, Sunrise (1872), where the sun appears to vibrate against a similarly luminous sky. Margaret Livingstone describes this as an illusion produced by the brain’s parallel processing systems: while one stream can clearly register the colored disc, the other cannot resolve its location—leading to the perceptual conflict that manifests as motion or glow.
Visual scintillation can also be triggered by: fine-scale edge transitions between equiluminant hues (e.g., red and green), saturated colors juxtaposed at low luminance contrast, or pattern interference from repeating or high-frequency color structures.
In studio practice, artists may intentionally or unintentionally create scintillation when placing saturated colors side by side without sufficient value separation. While this can produce a sense of optical energy or ethereality (i.e., an appearance of lightness, airiness, or visual instability that suggests something intangible or immaterial), it can also undermine spatial clarity and form articulation if not carefully controlled.
Understanding visual scintillation helps artists anticipate how chromatic and luminance relationships may interact within a composition—especially when aiming to evoke movement, vibration, or spatial instability.”
Visual Short-Term Memory (VSTM)
“A temporary memory system that retains visual information—such as shape, color, spatial location, and orientation—for a few seconds after the stimulus is no longer present. Unlike iconic memory, which holds more ‘raw’ visual input for only a few hundred milliseconds, VSTM allows for short-term retention and comparison of perceptual features at a higher resolution and longer duration. However, it is still limited in both capacity (typically holding 3–5 items) and duration (usually 2–4 seconds), and it does not support complex manipulation of information like working memory does.
In the Waichulis Curriculum, VSTM is an essential perceptual resource for tasks requiring short-latency visual comparison—particularly in exercises like Shape Replication and Gradation Blocks. These tasks often require learners to observe a visual element, shift their gaze or attention to the drawing or painting surface, and reproduce what was just seen with accuracy.
VSTM enables this process by acting as a short-term perceptual buffer, preserving key visual features just long enough to allow motor planning and execution to occur with meaningful visual guidance. To support and maximize VSTM, the curriculum emphasizes close spatial proximity between reference and drawing surface, minimizing attentional delays between observation and execution, and structured repetition to reduce reliance on memory and increase perceptual access.
While VSTM allows for slightly more abstracted representation than iconic memory (e.g., general shape rather than pixel-level detail), it is still subject to decay, interference, and compression. When the delay between viewing and execution grows too long, or when task complexity increases beyond VSTM capacity, learners may default to long-term memory schemas or conceptual inference—often leading to perceptual distortions or overgeneralization.
By understanding the functional role and limitations of VSTM, both learners and instructors can better design and pace observational exercises to maintain fidelity between perceptual input and artistic output. VSTM serves as a critical bridge between fleeting visual impressions and active motor execution.”
Visual Spillover
“A perceptual effect in which color, luminance, or form appears to extend beyond its physically defined boundaries due to contextual interactions and visual system heuristics. Visual spillover occurs when the brain interprets ambiguous or incomplete input in a way that causes perceived ‘overflow’—producing the illusion of radiance, diffusion, or chromatic bleeding where none physically exists.
While not a formal vision science term, visual spillover serves as an umbrella category for a variety of context-sensitive perceptual phenomena, including:
Neon Spreading: Chromatic colors appear to diffuse into adjacent neutral zones through edge-induced filling-in.
Glare Effect / Light Shedding: A region appears to emit light due to surrounding luminance gradients and soft-edge transitions.
Bloom or Halation: Bright areas create a halo-like softness, often interpreted as light overflow, particularly in high-contrast arrangements.
These illusions often emerge through mechanisms like edge contrast and lateral inhibition, which influence perceived boundaries, contrast gain control, which modulates brightness perception based on surrounding values, and/or perceptual completion, where the visual system fills in gaps or ambiguities to produce unified percepts.
Artists may deliberately trigger visual spillover by manipulating: gradient transitions and edge softness, particularly around light sources or saturated areas, compressed value structures, encouraging local brightness amplification, or chromatic adjacency, allowing high-saturation hues to perceptually extend beyond their physical edges.
In representational image-making, visual spillover offers a powerful strategy for simulating radiance, atmospheric effects, or emotive glow. However, it also requires careful calibration to avoid perceptual artifacts that may distort form or misdirect attention.”
Visual Tension in Pictorial Space
“The sense of dynamic energy or imbalance within an artwork’s composition, created by the interaction of visual elements that seem to conflict, pull, or push against one another. This tension is often used intentionally by artists to engage the viewer’s attention and create a feeling of movement, anticipation, or unease.
In pictorial space, the elements that create visual tension can include the positioning of objects, contrasting colors, the interplay of light and dark, as well as compositional techniques like diagonal lines, asymmetry, or overlapping forms. The tension occurs when these elements seem to be in a state of imbalance or conflict, even if the composition is static. This imbalance can make the viewer feel like something is about to happen or that there’s a need for resolution, even though the artwork itself may be still.
A classic example of visual tension can be seen in Cubism, particularly in works by artists like Pablo Picasso. In pieces like Les Demoiselles d’Avignon, the fragmented, disjointed forms create a sense of visual tension as the shapes seem to be at odds with one another, as though they are pulling the viewer’s attention in different directions.
Another example could be in the work of Baroque artists like Caravaggio, where the dramatic use of light and dark (chiaroscuro) creates a tension between light and shadow, contributing to the intense emotional atmosphere of the painting.
In summary, visual tension in pictorial space adds complexity and depth to a composition, often creating a more engaging or thought-provoking experience for the viewer. It plays on our visual instincts and psychological responses to dissonance, drawing attention and stimulating emotional or intellectual responses.”
Visual-Spatial Skills
“The cognitive and perceptual abilities that allow an individual to understand, interpret, manipulate, and mentally represent spatial relationships between objects or elements in a given visual field. These skills are essential for useful judgments of size, distance, orientation, proportion, and positional relationships—core competencies in observational drawing and painting.
In the Waichulis Curriculum, visual-spatial skills are developed through a progression of calibrated exercises that train learners to extract and organize spatial information with increasing precision and efficiency. Activities such as Shape Replication, Gradation Patterns, and Form Box Studies all serve to strengthen these capacities by engaging students in tasks that require constant comparison, projection, and adjustment of spatial relationships.
Unlike simple visual recognition, visual-spatial ability involves both perceptual encoding (the intake of spatial cues through vision) and cognitive transformation (the mental manipulation of spatial configurations). These skills enable artists to accurately assess tilt, curvature, scale, overlap, and alignment, and to mentally rotate or scale forms during compositional planning or proportional adjustment. Visual-spatial performance also plays a key role in:
Edge resolution (e.g., locating contour boundaries with spatial precision)
Perspective construction (e.g., mapping planar recession and foreshortening)
Form rotation and orientation (e.g., maintaining volume consistency across views)
Spatial memory and chunking (e.g., retaining position and proportion while drawing adjacent forms)
The curriculum treats these skills as trainable, not innate. Through repeated engagement with structured perceptual challenges, learners enhance their ability to accurately map and reliably reproduce spatial relationships. This development is foundational to achieving pictorial coherence, form fidelity, and creative fluency.”
Vitruvian System
“A canon of architectural and anatomical proportion rooted in the writings of Marcus Vitruvius Pollio (c. 80–70 BCE – after c. 15 BCE), a Roman architect and engineer. In his influential treatise De Architectura (commonly known as The Ten Books on Architecture), Vitruvius argued that buildings should reflect the proportions and harmony of the human body, which he described as nature’s most perfect creation.
Vitruvius proposed that ideal buildings—like ideal humans—were governed by rational whole-number ratios, not mystical constants. He emphasized the symmetry and modularity of body parts (e.g., the foot is one-sixth of the height; the face is one-tenth), establishing a framework in which mathematical regularity was both aesthetically pleasing and structurally functional.
This system was famously reinterpreted by Leonardo da Vinci in his iconic Vitruvian Man drawing, which visually mapped these proportional ideals onto the human figure. While often retroactively conflated with the Golden Ratio or Fibonacci sequence, Vitruvius’s approach was, in fact, arithmetically grounded—not geometrically mystical.
Within art training and anatomical studies, the Vitruvian system became a foundational proportional model during the Renaissance, serving as a precursor to academic figural conventions. However, its influence waned as Romantic, Baroque, and modernist movements introduced expressive distortions and compositional freedoms. The system experienced renewed attention in the 18th–20th centuries as part of revived classical studies and architectural theory.
In contemporary contexts, the Vitruvian system functions as a historical proportional scaffold, not a universal standard; is useful for introductory studies in figure construction and comparative measurement; and should be distinguished from formally abstract systems like Dynamic Symmetry or Le Corbusier’s Modulor, which rely on irrational proportions like √2 or Φ (the Golden Ratio).
While not formally adopted in the Waichulis Curriculum, awareness of Vitruvian conventions provides artists with a contextual understanding of how ideals of proportion have evolved—and how their use may shape viewer expectations, stylistic associations, or symbolic meaning.”
Voodoo Darkening
“An informal term used by artists to describe an unexpected and often perplexing darkening of oil paint passages as they dry—particularly in mixtures involving titanium white and carbon black. Unlike predictable phenomena such as sinking (where oil is absorbed into the substrate) or dark yellowing (a reversible discoloration due to storage in darkness), voodoo darkening manifests as a persistent value shift that lacks a clear, singular cause.
The observed characteristics of the phenomenon include a value shift: paint mixtures appear significantly darker upon drying than when initially applied, pigment combinations: most commonly reported in mixtures of titanium white (PW6) with carbon black (PBk6) or ivory black (PBk9), application thickness: thinner paint applications tend to exhibit more pronounced darkening, and surface appearance: the dried paint may display a slicker texture or subtle sheen differences compared to surrounding areas. Potential contributing factors include:
Pigment Particle Size Disparity: Titanium white has a much finer particle size (~0.3 microns) compared to carbon black (~10 microns). This disparity may lead to a phenomenon known as flooding, where finer particles rise to the surface, altering the paint’s optical properties.
Binder Absorption: Variations in the absorbency of the ground or substrate can cause uneven binder distribution, affecting the paint film’s translucency and resulting in perceived darkening.
Refractive Index Changes: As the oil binder oxidizes and polymerizes during drying, its refractive index changes, potentially influencing the way light interacts with the paint film.
Microstructural Changes: The spatial distribution and orientation of pigment particles within the drying film may affect light scattering, contributing to the darkening effect.
Voodoo Darkening may share characteristics with some other observed phenomena in oil painting, but it is currently understood as distinct from: sinking: typically results in a matte, dull appearance due to oil absorption into the substrate, which can often be remedied by oiling out and dark yellowing: a reversible yellowing that occurs when paintings are stored in darkness; exposure to light usually restores the original appearance.
Practical implications for artists include: testing: conducting test swatches with specific pigment combinations can help anticipate potential darkening issues, layering strategies: applying paint in multiple thin layers and allowing adequate drying time between layers may mitigate the effect, medium selection: Adjusting the oil-to-pigment ratio or experimenting with different oil mediums may influence the drying behavior and documentation: keeping detailed records of pigment combinations, mediums used, and application methods can aid in identifying patterns and preventing future occurrences.
While the exact mechanisms behind voodoo darkening remain under investigation, awareness of its potential and careful material handling can help artists manage and possibly prevent this phenomenon.”
Volatile
“In the context of art materials, volatile refers to a substance’s tendency to evaporate readily at room temperature, typically due to a low boiling point and high vapor pressure. Volatile substances transition quickly from liquid to gas, making them especially relevant in the formulation and behavior of solvents, thinners, and certain media components.
Volatility plays a central role in the drying rate of paints and varnishes, where faster evaporation can aid or disrupt application depending on timing, the manipulation window for paint films, particularly in brushing or leveling behavior, as well as health and safety concerns, as volatile compounds may emit hazardous fumes and are often highly flammable.
Common volatile solvents include turpentine, mineral spirits, acetone, and alcohols—all used to dissolve, thin, or clean materials. These substances leave no film or binder residue; their sole function is to modulate viscosity or surface behavior before completely evaporating.
Mayer distinguishes volatile materials from non-volatile binders, which form the actual film upon drying. Volatile components must be chosen with care to match the evaporation rate to the working characteristics of the paint or varnish, thereby avoiding disruption of underlayers by evaporating too quickly and preventing retention that could leave a gummy or uneven residue.
The introduction of commercially distilled volatile solvents in the 15th century—such as turpentine—marked a major advance in oil painting technique, enabling thinner applications, faster drying, and greater control over surface finish.
A volatile component is thus defined not by its solvent strength, but by its rate of physical dissipation—a behavior critical to both the manipulation and the longevity of painted surfaces.”
Volatile Organic Compound (VOC)
“A carbon-based chemical that readily evaporates into the air at room temperature, often producing vapor that can be inhaled. In the context of art materials, VOCs are typically found in solvents, thinners, adhesives, and some synthetic resins used in painting, varnishing, and cleaning operations.
VOCs are classified by their chemical volatility (i.e., evaporation rate) and their molecular composition. Common VOCs in the studio include turpentine, mineral spirits, acetone, xylene, toluene, and alcohols—many of which are used to alter viscosity, clean tools, or dissolve binders.
The key characteristics of VOCs are that they are volatile: they transition easily from liquid to vapor, they are organic: they contain carbon and hydrogen atoms, often with additional functional groups, and that they are airborne: they disperse into the studio atmosphere during and after application.
According to Mayer, virtually all volatile solvents used in art are toxic to some degree, with health risks depending on concentration, duration of exposure, and ventilation quality. Even ‘mild’ solvents like turpentine are subject to federal poison-labeling regulations due to their volatility and potential to cause respiratory, neurological, or dermal effects when inhaled or absorbed.
The implications for studio use include that VOCs affect drying time, film formation, and working properties of paint films; that prolonged exposure in poorly ventilated areas may lead to chronic health issues; and that VOC limits are often regulated in indoor air quality guidelines, particularly in schools or other institutions. As such, artists are encouraged to work in well-ventilated areas, use local exhaust systems when possible, and employ low-VOC or VOC-free alternatives. Additionally, they should wear protective gloves and masks when handling high-concentration compounds.
Understanding VOCs is essential not just for material manipulation, but for maintaining long-term health and regulatory compliance in studio environments.”