Painting Light and Shadow digitally--the "rules"?

[phix95]

I've looked through the forums re: light and shadow and found some info but still don't have all my questions answered. I didn't see this topic in the Digital forum so if it is here already, sorry.

Things I've heard and sometimes observed:
*shadow colors are often the opposite temp. of the light color
*shadow colors can sometimes (in what situations?) be the compliment of the object.
*Shadows outside are often blue-tinged b/c of the ambient color of the sky
*I've read from another tutorial on deviantart that shadows are less saturated and highlights are more saturated (than local color).

Questions:
*It seems to me that a CAST shadow is often the color of what its being cast ON, darkened, a bit muted, and has some ambient color mixed in. I usually don't see the color of the object doing the casting, in the shadow. I think if I do see red in a shadow being cast from a red object, it's reflected light--am I wrong here?

I have more but they're not coming to me right now...

Just now, I made an observation--I'm writing this in my room with two light sources--my monitor and a warm lamp light; the shadows cast from my keyboard are colorless--just very dark, except on the termination of the shadow--it gets orang-y. The color of the surface my keyboard is on is a light, warm wood color. But when I hold my had above that surface, the shadow cast by my hand is bluish. So is the shadow from the keyboard coming from light cast by the monitor, and vice versa for my hand (using the cool light, warm shadows and vice versa rule)? I'm trying to have a few "rules" so when I paint something from my head, it reads correctly.

Another, relatively less pressing question is how do you lay down colors painting digitally? For instance, it seems logical and less confusing to me to paint your subject its local color first (kind of like blocking), then using a lower flow brush, paint a layer of the shadow or light color atop it--rather than pre-mixing the local color and shadow/light color FIRST. What do you think?

[Elainepsq]

Hi, Welcome to WetCanvas and the digital forum.
One of the first things I try to tell my students, is that there are no rules, if it works for you, it's okay. And many approaches that work for one artist may not work for another. I'm sure you will get many different opinions on these questions all very valid for each particular artist.

Many painting instructors I've worked with believed in dealing more with the values -lights vs. darks -and the intensity -brightness vs. grey- of the color and less with following local colors. I tend to make my shadows cool, and add some warm tones to something that I want to bring out to the foreground. If I want to make something really stand out, I will us strong contrast, often with complimentary colors to make it really pop. My personal style is to keep my colors lighter and brighter than they appear in the real world, but again, that is a matter of person style.

As for your last question, while that sounds like a good approach, working digitally it may depend on the software you are using. I have been painting most recently with Artrage, but have also used Painter and Photoshop. Keep in mind some of the advantages you have in most digital programs that you don't have in traditional media. To make subtle shadows in Artrage, I will use a very transparent airbrush. I never used an airbrush on a watercolor or Oil painting. I can mix oil and watercolor in Artrage, but I'd never dream of putting oil paint on watercolor paper. If you are working in a program that has layers, you can take advantage of different opacities of the layer and using various blending modes.

I hope this has helped.

[LavenderFrost]

Warm light, cool shadows. And vice versa. The shadow will be the opposite colour of the light. This topic came up in the acrylic forum once.

I have used both methods you mention, depending on the situation. Whatever works.

[MvdLinden]

Great topic. No simple answer, unless you are trying for a photo-real look.

The human visual system is not a camera. The eye takes in data in a holistic way that includes color, intensity, texture, perspective, relative size and position. The Brain, primarily the visual cortex, then processes that data to construct a scene. If you understand the "rules" of human perception, then you can play with deconstructions and reconstructions of the data which can give you room to play with things like shadow and color far beyond what would be implied in a camera view of reality.

the topic is a bit to involved to lay out here, but a good book on the subject is: Art and Visual Perception: A Psychology of the Creative Eye. Rudolf Arnheim, author.

[phix95]

Right. There are rules so to speak, that nature dictates. Things are how they are b/c of wavelengths, atmosphere, amount of light, whatnot. I'm just trying to have a few that people have recongnized to rely on. I know it's somewhat complex, but I don't like to just guess. Sometimes I see things negating the warm/cool rule for example, and I'm not sure why that happens.
Plus my questions in my first post.
I will look at that book.
This book, Color and Light: A Guide for the Realist Painter, has been referred to a lot in other forums. It's on my wish list and hope it will also explain some of my questions. It's not for digital but I hope I can understand it anyway.

[birdhs]

This is a question that has just been addressed nicely in the April 2012 issue of Artist Magazine in an article by Jan Kunz, How Does Your Garden Glow, page 61.

If u don't have this mag I suggest buying it, or at the least, get it the book from her by the same title from North Light books.

I think this is a topic that you can study from many different sources, most of my best info comes from buying used art books and reading magazines. I also take classes which are very helpful. There have been no shortcuts for me, just study and practice - practice - practice.

And asking lots of questions, and taking notes.

But most of all-- enjoy the process of learning.

life is good

greg