With the next few posts on this blog , I will attempt to share some of the notes from the upcoming Exploring Color Workshop. After the workshop, I'll post some images and findings.
If you've been reading the posts on color in the past, you know at least two things about me by now. One, that I use a basic, limited palette, and two, I enjoy finding exceptions to the rules. This is not to say that to be a student of mine, you must adapt to my palette, or that the "rules" don't work much of the time. Having said that, this workshop is going to stir some waters for sure.
Studying color and color science is fascinating to me. Whether or not someone understands it all does not necessarily make him or her a better artist. [Thank goodness.] I am sure the majority of wonderful artists (in our past as well as present day) cared little about this. Perhaps they have, through painting miles and miles of canvas, developed a natural response to the effects of light and color. But I truly enjoy this stuff, and hope that with a classroom of like-minded seekers, we will find some fascinating answers.
Here I must give a HUGE amount of credit to my husband for helping me wade through and understand how to present this stuff. Thank you Mark!!
Exploration One: Visual Illusions, Part A
A major "bottleneck" for all color perception is our eye, where all wavelength combinations end up as stimuli for the three, photoreceptor types. (Hang in here with me just a bit). Color vision can be described scientifically as an additive process (combination of red, green, and blue, one of the color modes you are accustomed to if you use Photoshop or other photo editing software); or as the inverse, a subtractive process (lack of RGB, that is cyan, magenta, and yellow, another of the color modes you may be familiar with if you have ever been a graphic designer preparing materials to go to a traditional printer.) HOWEVER, artists have universally adopted a phenomenological way of describing color: as value, hue, and chroma.
If you are an experienced artist, you are aware that...
- Paint pigment mixing of light is a combination of both the additive and the subtractive processes. (click here for diagram). Light bounces off different pigment molecules on the surface and is mixed additively in the eye, but light also passes between the pigment molecules (through extenders and mediums), bounces off the ground (that is the painting surface), and back out through the paint which subtracts certain wavelength of light (hues.) This is especially important for OIL painters to understand. It is the essence of why oils can produce effects that say, acrylics, for example, cannot.
- Different pigments may look like they have nearly the same color, but actually transmit quite different spectra. This is due to the fact that we are not all perfect "see-ers" of color. Widely different spectra look alike as long as they evoke the same activation triplet in the 3 receptor types in our eyes.
Okay, so now is when, if you were in the workshop, we would do a little experimenting and discussion to recognize this phenomenon. Just keeping hanging in with me.
Before I go any further, I want to make sure you understand a few definitions so that I can use color terminology freely:
- Hue: the perception of how similar the stimulus is, to one of the named colors: yellow, orange, red, violet, blue, green.
- Value: the perceived lightness or darkness of a surface. It is described relative to an imagined white surface.
- Chroma: the strength of a surface color. It is described as the degree of visual difference from neutral grey. The have high chromas, a surface must reflect light of high spectral purity (called saturation.)
- NOTE: The possible range of chroma is strongly dependent on value and hue. At maximum value (white) and minimum value (black), chroma can only be zero. As we move away from these extremes, the range of possible chroma increases, up to a maximum at a value level that depends on hue--high for yellow, low for violet-blue.
- Brightness: the perceived intensity of a visual stimulus. (more on this later... it's the good stuff.) Brightness is a term probably used more by a non-artist to describe a painting and is a combination of relative hue, value, and chroma.
- Colorfulness: is the perceived intensity of chroma. Surfaces with high chroma tend to reflect light of high "colorfulness," the latter varying, however, in proportion to the level of illumination. Therefore, a "colorful" painting has pigments that are high chroma, not just bright. Again, colorful is a term used more widely by non-artists, and is a combination of relative hue, value, and chroma.
Strictly speaking, hue, chroma, and value are all psychological dimensions of subjective perception. Tonal realist painters systematically judge the brightness and colorfulness of the light coming to their eyes from the subjects. In general, they do not think in terms of absolute measures of these parameters, but in relationships (between the different components of their subject). They typically think of these relationships of brightness and colorfulness in terms of the value and chroma of the paint mixtures that they will use.
So that's enough for now. You're wondering why you even began reading this and how in the world you will ever use it to help you achieve your color intention. This is just some necessary foundation for the good stuff to come. Promise!!