Value Scale in art is referring to the "range" of darkness to lightness within your painting. The more range the more realistic things will appear.
Value is the term used to describe just how dark or how light areas and objects are within your painting. Scale is refering to a linear change.
You will notice in some styles of work, the piece is mostly dark (giving an ominous or sad feeling to the work) or mostly light (giving a brighter or happier feeling to the work).
In most realistic work you have a balance that encompasses the entire spectrum from your darkest dark to the lightest light. This balance of value scale in art helps to make the difference between an amaturish and a professional looking painting.
Its hard to talk about value in a colored world, but it applies there as well. Lets work with the value scale for the rest of this lesson in the black and white world. Or what we call in classical painting, the dead layer.
Within the dead layer you have your extremes and a range of grays
that on a value scale can go from the lightest light to the darkest
When used correctly you can create the illusion of form, or a 3D appearance to your work. Ever wonder why in some work by beginners, the shape of the object appears right, the colors look ok, but the apple just kinda looks flat, plan, or stick-figur-ish. (That's hillbilly for cartoon-ish).
Sometimes, this is what the artist wanted, but in a lot of cases, its just that the artist didn't use the full value scale range afforded to them in their materials.
In oil painting, your whitest white is going to be your white paint. Your darkest dark will be a mixture of black, burnt umber and prussian blue. I talk about and show this in great detail here in the dead layer.
The value scale in art really isn't that difficult once you've seen it done.
Check out the video below when you're done with the lesson.
Most artists will use a 5 to 9 graduation in between the darkest dark, and the lightest light. Lets look at this value scale.
When you mix your grays, use your computer to print out this gray scale as a guide. You can also get this scale on the internet or at your local photography shop. I always keep one close by for checking my mixtures.
Practice by mixing and matching your grays to the scale. You can even place just a touch of paint to the paper to see really how close you are.
Once you've got 5 to 7 grays, you will have ample paint to make a value study (dead layer).
Lets take this apple for an example. Breaking down the image, I've separated the lights and dark's in this picture.
Matching the gray section to the corresponding area within the subject, you get a rough (blocked in) image. After laying in your paints to the designated zones, you can then begin the fun part of correcting/blending.
This sometimes takes longer than applying the paint! Using the dry (usually an older short haired worn out) brush to begin with. Then moving to the mop brush to set the paint and remove unwanted brush strokes gives you your completed value study.
This is such a powerful tool in assuring your work will look realistic. I also believe its one of the most important skills you can learn as an realistic artist. When you have mastered the value scale in art and incorporated it into your painting, success of your work in almost guaranteed!