Friday, March 26, 2010

Exploring Color Workshop: The Follow-up

The weekend workshop was beyond my expectations. The ten students worked so amazingly hard. Thanks to all of you!

Over the course of the weekend, students worked on four, separate, explorations.

Exploration 1: Two colors, without regard for subject

Exploration 2: Color relationships, from gray slide

Exploration 3: Color schemes and mood schemes, from a gray slide

Exploration 4: Grays and saturated colors, from a color slide

Below is an example of exploration 2, an illusion, and the results.

click to go to the working illusion link

The squares in the centers of these two boxes above are the exact same.

Given an assignment based on this illusion, students came up with these results:

The shadow piece on the house in pictures 1 and 2 are the same color, a very pale neutral which leans toward green. The shadow piece on the house in pictures 3 and 4 are the same color, a mid-value neutral which leans toward violet (as seen in the illusion example above).

How do the relationships affect each other in terms of color, value, and hue?

Which painting looks more believable; which more light-struck?

How can this be used new found power be used for good, rather than evil?

Through our discussions, viewing the works of Quang Ho, sampling colors from slides of Sorolla's work, and by sharing each of the student's exploration results, we left with an open mind and a charge to explore more.

For more information on when this workshop may be offered again, please email me or visit the link to my workshops often.

Sunday, March 14, 2010

Exploring Color Workshop: The Prequel, C

The mind did not evolve to see the world "as it is,' but to see the world in a way that proved useful to see in the past. In short, the brain evolved to continually redefine normality by finding the relationships that were useful in our evolution and development.

Everything we (or our ancestors) have seen goes to inform how we see the world. That is why we can interpret a visual image as a 3-dimensional scene, and our visual system immediately estimates a lighting vector and uses this to judge the property of the material. Ah, but try to translate that 3-D on a 2-dimensional surface, and you have to "undo" all that your brain has learned to understand about space and perspective, and re-learn to see what is actually there. That is why if you are painting a model from life, let's say she is reclining with her lets bent (as if curling up in a ball), tops of the feet toward you and her head away from you, her hip may fall in the same horizontal line as that of her breast. The same is true with the "undo-ing" of light and shadow illusion.

The visual system needs to determine the color of objects in the world. Just measuring the light coming from a surface (luminance) is not enough: a cast shadow will dim a surface, so that a white surface in shadow may be reflecting less light than a black surface in full light. The visual system uses several tricks to determine where the shadows are and how to compensate for them, in order to determine the color of "paint" that belongs on the surface.

In the painting shown above, it is truly believable that the flat, highly reflective surface on which the lemons and vases sit, is only made up of one material... not many different materials all tiled together. Yet the differences in color along the table's surface is varied. Our brains believe it when we see it "live" just as they believe it here. These changes along the surface of the hutch are due mostly to the reflections of surrounding objects.

Now, imagine that you are looking at a shiny new red car. It is sitting in bright sunlight. The top of the hood is reflecting the highly chromatic red paint. But does it look red... as in the color out of the spray can that was used to paint it red?? Now, follow the curve of the fender, the surface moves into shadow. Still, your mind compensates for the less intensely reflected light and perceives that the paint on the fender is the same color used to paint the rest of the car. How does your mind do this?

The first trick is based on local contrast. In shadow or not, an area that is lighter than its neighboring area is probably lighter than average, and vice verse.

The second trick is based on the fact that shadows often have soft edges (at least at some point along them), while paint boundaries have sharp edges. The visual system tends to ignore gradual changes in light level, so that it can determine the color of the surfaces without being misled by shadows.

The brain also uses statistically abundant experiences to perceive mad-madeness. When confronted with a line or form that is unnaturally symmetrical or precise, the brain interprets changes in the surface color rather than in terms of shadows or lighting.

Of course as artists, we know that we should not just think of the car's hood as red and the car's fender as red any more than we should think of the top of the hutch in the painting as brown. We know that we should think of each of those surface planes as different colors altogether, (everywhere there is a plane change, there is a color change)... and that along with those plane changes we also experience colors bouncing from surrounding objects. So here again, we are having to re-learn what we are really seeing, to stop ignoring the truth, and to ignore what our brain wants us to perceive, which is that the car is red and the hutch is brown.

Have you ever painted a painting and wondered why it isn't believable in terms of color? Perhaps it is a white wall in shadow, and you opt to go overboard based on the success of someone else's painting you thought you understood. Now, it looks like a blue wall rather than a white wall in shadow. As with many so-called illusions, this effect truly demonstrates the success rather than the failure of the visual system. The trick as artists, is learning to use these illusions for good (rather than evil)... that is, to know when to use them and when not. This is where your visual intention must supersede your power of the knowledge of color. Restraint is often times the higher road to take.

Wednesday, March 10, 2010

Exploring Color Workshop: The Prequel, B

Exploration One: Visual Illusions, Part B
The painting above, "Voices in the Sunset," has very little applied color. That is, if you saw these mixtures of paint puddle out of context, you would think them all mostly neutral. Put side by side in a painting, using the information you're about to read, and it looks like it has a lot of color doesn't it? We will spend one session of the upcoming workshop to explore this theory.

Before proceeding, you may want to print out the previous post (same name as this one but Part A) and keep the definitions part handy while reading this.

The process of color information by our visual system seems to operate in three successive stages:
  1. Trichromatic image capture: color information is recorded by the responses of the cone cells in the retina.
  2. Opponent processing: responses from the cones are converted into three signals, for brightness (value), yellowness vs. blueness, and redness vs. greeness. The latter two providing our perception of hue and saturation.
  3. Processing for color constancy: information on changes in hue, value, and saturation across the visual field is analyzed and resolved into an interpretation of the hue, value, and chroma of the visible surfaces.
Step #3 is the most interesting for us in this post. The brain decodes the visual input and then scans all of the data for variation, not for absolute data. We see always by comparisons. That is, variation in color is what gives meaning to visual input.

Stop here and go to this visual illusion by R. Beau Lotto, or visit The blue tiles on the left cube and the yellow tiles on the right cube are actually the same.

The human visual system is not very good at being a physical light meter, but that is not its purpose. The important task is to break the image information down into meaningful components, and thereby perceive the nature of objects in view. This method of visual input has developed in humans to make us efficient see-ers. For example: relative "brightness" (remember that is the perceived intensity of value, hue, and chroma all rolled into one) is thought to be used by the brain to process motion, form, and texture!! WOW!

We know:
  • The brightness of equally intense stimuli changes with their relative saturation and with shifts in hue. Under consistent light conditions...
  1. More saturated (pure) colors appear brighter than less saturated colors (i.e. strongly colored stimuli appear brighter than grey stimuli). Okay... that was an easy one.
  2. Red and blue colors appear brighter than yellow and green colors. (The reason that often times in the distant landscape you can still see the violet hues, but no the yellow and green).
This is likely to be an adaptive solution that evolved within the human eye and visual cortex to help identify more reflective surfaces (which are more saturated and would need to stand out in an environment of vegetation).
  • However, the retina has a lower sensitivity to short wavelengths (blues). Therefore, a neutralized yellow may be perceived brighter than a pure blue.
  • In general, contrast enhances the difference in brightness and/or color between interacting areas of an image. Such contrast effects are mutual, but if the surrounding area is larger and more intense than the area it encloses, then the contrast is correspondingly out of balance. (Think, light holes coming through trees here).
  • Because the brain does not read visual stimuli in absolute terms (like an objective measuring device, sending raw light and color data to the brain), there can be failures of color constancy (see #3 above). The visual appearance of a surface color can be influenced by adjacent and interspersed colors respectively. Here are some samples of simultaneous contrast illusions.
  1. Simultaneous contrast of lightness: Patterns of moderate contrast appear to have more contrast in a low-contrast contest. Vice-versa, the same pattern appears to have less contrast in a high-contrast context. Think about this and how, let's say, the appearance of contrast between painting a sunset painting and painting a "dusk" painting are different in the way we would handle the contrasted areas with those areas similar in value.
  2. Simultaneous contrast of hue and chroma: A purplish-red color looks more purple against red, more red against purple, lower in chroma against bright purple-red, and progressively higher in chroma against dull red-purple, grey, and green. Just read that a few times and think of how you use analogous colors and neutrals in your own paintings to, as the galleries tend to say these days, give your painting more "punch."
  3. Simultaneous contrast of lightness and chroma: The same purple-red looks darker against a lighter, and lighter against a darker color of similar hue and chroma. Don't over think that one. You know it; you've just never written it in words before.
  4. Simultaneous contrast of hue: When a medium grey is seen against a background of similar value hue, the appearance of the color moves toward the hue of the additive complement. For example, the medium-grey figure against a red background shifts the perceived red background toward cyan.
Stop here and drool over Sorolla's "Desnudo de mujer" . See how easily the skin tones turned toward green when painted next to the pink satin.
  • An important special case of simultaneous contrast of hue is the phenomenon of complementary colors in shadows. When we have a strongly-colored main light and a neutral secondary light source, the colors in the shadow of the main light shift in appearance toward the complementary color of the light. (Do not confuse this phenomenon with the hobby painter's recipe of adding the complementary pigment of the color of the object to get its color in shadow). The induced complimentary effect is the basis of the artists' conventional rule (you know how much I hate rules) of warm lights creating cool shadows and vice versa.
Simultaneous contrast is responsible for the well-known artists problem that paint mixtures look quite different on the palette (especially a white palette) to their appearance on the painting. Experience and a growing capacity to see colors independent of their context can help here. The strategies of using a colored (that is stained) ground closer to the tonal level of the finished painting than a stark white, or of covering the canvas at an early stage with a mosaic of flat colors* can both minimize problems caused by simultaneous contrast on canvas. The colors in any painting have a fixed relationship to each other, and it is the business of the painter to get these relationships right.
*Kevin Macpherson states in his second book, "Landscape Painting, Inside and Out," that he often mixes his colors for a painting on a canvas panel. Once the panel-palette is dried, he sometimes uses that mosaic of colors as the foundation for a painting.

Hang in there... one more point for today...
Assimilation (reverse contrast) is a phenomenon having the opposite effect to simultaneous contrast, and is seen when small areas of color are closely interspersed. Reds look more purple beside blues and more orange beside yellows. The lightness of white or the darkness of black may seem to spread into neighboring regions. Similarly, colors ma appear to spread into or become assimilated into neighboring areas. All such effects tend to make neighboring areas appear more alike, rather than to enhance their differences as in the more familiar simultaneous contrast, hence the term "reverse contrast."

The Op Art movement of the 60s featured painting and sculpture that exploited these optical effects to create perceptual ambiguity created by colored surfaces, and to suggest movement created by lines and patterns in black and white.

Saturday, March 6, 2010

Exploring Color Workshop: The Prequel

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...
  1. 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.
  2. 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!!