Painting Color Over a Monochrome Underpainting - Part 1: A Face
As promised, here is a brief overview of how I approach painting flesh tones over a completed monochrome underpainting. This approach uses straight tube colors applied opaquely, as opposed to my approach to painting hair using transparent glazes, which I’ll discuss in my next post. Before I begin, let’s get up to speed. I have completed a monochrome underpainting in oil, using a palette mixed from titanium white and a neutral black mixed from three parts ivory black to one part burnt sienna. For this, I’m using Windsor Newton professional oil colors. I get pretty detailed with my underpaintings and try to be as accurate as possible with respect to value and form. This is because I want to work out every issue not related to color in the under-painting. I find that most of the time this translates (contrary to intuition) into a faster painting completion time and that it ALWAYS translates to a better-finished painting. So: Flesh tones! I’ve tried multiple techniques for painting color over monotone underpainting to get good flesh tones. Multiple transparent glazes, transparent glazes plus opaque paint, and straight-up opaque colors. I’ve settled on opaque colors with no medium for painting the color pass for all flesh tones. The main reason for this is that it gives so much more control. With opaque colors, I have complete control over the hue, value, chroma, and all the other intricacies of blending with the monotone being a great assistance for placement. Using the underpainting as a guide for all value/form decisions and my reference material as a guide for color decisions, and using my color string flesh-tone palette mixed as described here, I begin a single color pass over the underpainting. I start in an area of mid-value and try to mix a color that fits that value and is also the right hue and chroma. Using the color string palette, I hone in on the value range first. Then I make a guess as to the hue… yellow-orange-red. Last, I knock back the chrome (color intensity) with the addition of a neutral string. I test the color of the painting. In the video, you may sometimes catch me doing this, even though the video is sped up. I’ll place color on the painting, and it is immediately apparent whether it is too light or too dark. Whether the color is correct is another question, but that is the problem I am trying to solve in the color pass. The underpainting tells me immediately if the value is wrong! I move out from my starting point, mixing color as I go from the color strings on my palette. First, think of value (based on the underpainting), then of hue (yellow, orange, red), and finally of chroma (color vs. neutral). As I go, I often have to re-evaluate my color choices, and go back and correct them. But my value choices are already made. Very seldom do I need to adjust the value of a color…and if I do, it’s often a case of my having mistaken a high level of chroma for a darker value when painting the underpainting…something I still do, even though I am aware that it is a common error. For example, a local hue change toward red is often easily mistaken for a darkening of value. I always keep several rules of thumb in mind when painting flesh tones, but am aware that exceptions exist.
Flesh tones are most often lower in chroma than you think.
Anywhere there is a concentration of blood flow (fingertips, ears, etc.) there will be an increase in chroma.
Anywhere that light passes through the translucent layers of skin, particularly at the boundaries of light and shadow, there will be an increase in chroma.
Areas where veins pass close to the surface often see decreased chroma.
Areas facing other areas of flesh tones will experience reflected light from the nearby skin and will see highly elevated levels of chroma, especially in shadows.
These ‘rules’ are good to keep in mind, but I do not ever advocate following rules if they contradict what you see. What you should do is always try to understand what you see, especially if you are using photographic reference material. Always keep in mind the limitations of a photograph. You will always lose detail in either the high values or the low. Cameras do not transition well between the two. Modern digital cameras run algorithms that try to normalize colors and exposures to fit expected situations. I never trust them. If you need to paint from photo reference, try to control the camera as much as possible. Shoot RAW if you can. Try to remember the scene. Look for the weaknesses in your reference material. Shoot a wide range of exposures and a few degrees of vantage on your subject so that you have more than one image to rely on when painting. In the end, rely on your own aesthetic judgment. To this last point, I will often shut off all of my reference material for the last few hours of painting, and focus on making adjustments that suit my vision for the composition as opposed to seeking accuracy based on my references. In my next post, I will contrast this approach with the one I take when painting hair/stone/etc., where glazing is my preferred technique. For the record: the video is set to a lovely nocturne piano piece by Chopin, which I do enjoy, but I can almost guarantee I was actually painting to a playlist of the Pixies, Mother Mother, or Oingo Boingo.Update: Part 2: Color pass-over hair is up here.