Reference photos & acrylic underpaintings. Two in black and white, one in color.
First let me start by saying that these comments are my interpretation of a painting process that I have successfully used for many years. Each artist should experiment with different methods and choose for themselves. Although this is written with landscape painting in mind, the ideas also pertain to still-life painting.
I have found that there are four basic problems common to every painting – composition, shapes, values and color.
By laying in an underpainting in tones of black and white you are solving the first three problems - composition, shapes and values.
Composition and shapes go hand in hand. Ignoring details, I look for the general shapes, balance and variety. I move components, eliminate some and alter shapes all for the benefit of the composition. I try to make my shapes correct knowing that I can alter them a little, but not make major changes, when I am in the painting stage. This is not a color-book style of staying in the lines, but I need to know that my shapes and angles are reasonably correct.
Values. I keep in mind that with overhead light from the sky, the horizontal planes are the lightest, the angled planes a bit darker and the vertical planes the darkest. This changes if the source of light is low (sunset, sunrise). The lightest plane is always perpendicular to the source of light. Planes get darker as they angle away from the direct light. It is important to determine your light source and its direction then state the value of the planes accordingly. The light direction will also determine the placement of your cast shadows. Aerial perspective is a result of values decreasing as they recede into the distance.
After managing these three problems as correctly as possible, my underpainting is done.
Now I only have color to worry about. My foundation is complete. Color theory is a complex subject and we can talk about that at another time. I determine the color of my light and adhere to the rules of aerial perspective as I work to mix the colors in the values that I have predetermined in my underpainting.
Oil paints are not as substantial as you might think. Many of our oil paints are transparent, especially the dark colors. Covering a white canvas with transparent dark paint can be difficult unless you lay the colors in thickly and then you have the problem of working into thick, wet paint.
Having the gray values in place allows you to apply these transparent colors as a glaze, making this thin application of oils look rich and substantial. Then the lighter and more opaque colors can be easily applied over this thinner paint.
Underpaintings can be done in shades of gray, using black and white, or in color with bits of the color allowed to show through the finished painting. You can also glaze your underpainting with a thin wash of oil paint if you desire a colored base.
Acrylic paint, if thinly applied, dries in about 5 minutes and you are ready to go. If you choose to do an underpainting in oils the drying time will be longer. I prefer to use an acrylic underpainting in my studio as it is odor-free. Painting outside, I use an oil and turp mixture for my underpainting. The mixture dries quickly in the sun and the vapors from the evaporating mixture aren't noticeable outside. In a studio setting the oil/turp vapors would be very annoying. And, yes, you can paint oil over acrylic if you keep the acrylic layer thin.
If I stay true to my underpainting I will have a better chance of a successful painting. I have, on occasion, strayed, and always came away disappointed with my results. Good painting takes lots of practice, concentration and discipline as well as knowledge. I find that breaking a painting down into logical steps makes the painting process easier. The phrases – “thick over thin” and “light over dark” bring to mind the importance of “working from the general to the specific”. Each stage should be as correct as possible before moving on. Oil paint looks richer if applied in two coats. Don’t move on to the second coat if the first one isn't correct. If you must correct an area, it's best to wipe it out and reapply the paint.
An underpainting helps to simplify the difficult process of painting. I hope you will try it for yourself.
I look forward to your comments and questions.
Thank you for visiting with me today.