RELIEF, unlike painting, utilizes light as a separate variable from color. Mathematicians know that adding another variable to an equation can exponentially increase possible solutions. This is why RELIEF opens up a vast new visual space to be explored. My life has and continues to be spent exploring as many of those solutions as I can.
PAINTING: When white light strikes a painting's flat surface comprising color (pigment) and medium (oil, acrylic...), one portion of the light is directly reflected off the surface and much of the remaining portion is refracted (absorbed by the pigment and reradiated as color). Painting and digital media convey only the refracted portion of light to the eye. This refracted portion of light is incoherent, meaning it loses all the information contained in the original light source except for its intensity and the wavelength signature of the pigment. Snell's law governs: in a mirror or gloss surface, the reflected portion bounces off the surface at the same angle as it arrived. If the surface is matte, the light is scattered off the tiny matte surfaces. The absorbed, refracted portion is reradiated roughly equally in all directions.
The proportion of direct reflection and absorption reaching the eye depends on the kind of pigment and medium, on the matte or gloss properties of the surface, the angle of illumination, and the position of the viewer. Ideally what we see in a painting is a portion of the absorbed light reradiated from the pigment. The color we see is that portion of the white light spectrum not absorbed by the pigment and reradiated. A red pigment absorbs all of the spectrum except red.... Thus pigment color is said to be subtractive. The percentage of reradiated color depends on the pigment. Photographers use an approximate grey scale with white being 100 percent, yellow dropping to 80, red, green, blue. continuing down to..black 0.
In the case of pastel, almost all the light is absorbed since the pigment predominates and the surface is matte. In the case of oil, a larger portion of the light is reflected. Sometimes it becomes difficult to see an oil painting if it is poorly lit so that the surface reflection overpowers the refracted color. Water color paintings often employ transparent pigments to increase color by allowing some refracted, colored light to bounce off the white paper surface back thru the pigment. Acrylic paintings inhabit a middle ground since acrylic medium is less transparent than oil or water color medium. The Impressionists avoided mixing subtractive pigments and dabbed colors side by side to increase color reaching the eye. This led to pointillism, and present day photography, television screens, and digital imagery.
RELIEF: Relief employs all of flat painting's refracted light but then adds the direct reflection portion. This reflected component can be manipulated by how that portion of the surface is "carved" relative to the light source and the viewer. The reflected light is also coherent, meaning that, like a mirror, it retains the information provided by the source of illumination.I believe that the eye's has a holographic sense due to an ability to differentiate between the reflected and refracted light components, based on the opposing distributions of cones and rods in the retina.
Illusions are possible in relief because although we have binocular vision with each eye seeing a slightly different image due to their separation, we cannot detect the absolute distance from an object to the eyes. The eyes are relative instruments, which record and compare light information received at each point to that received at adjacent points. We seem to have a general holographic ability to see "visualize" in 3 dimensions, but it, too, is relative and approximate. What this means is that the eye can misread a complex surface at a distance similar to viewing an impressionist painting and fixates on the image presented as opposed to the actual surface that creates it.
In 2014 I began a series of conceptual reliefs to explore how we interpret the interaction of light and color which has opened a door to many compositional elements. Here are photos showing how relief images change as their lighting changes.