What is a Value Scale?
A value scale is a simple drawing tool that helps you see and draw values by comparison. The scale to the right has a sliding range of values on one edge and ten gradated sections on the other edge.
How to use a Value Scale
Let's say you're drawing a portrait of someone with blond hair. From any distance away, hold the value scale next to the hair, squint your eyes, and, see what part of the gray scale matches. Then check the value against the drawing.
Take as many "readings" as you need too. For example you could check to see what value the highlights, mid-values, and shadows of the hair are.
How To Draw A Value Scale
If you're trying out a new brand of drawing paper, it's very useful to draw a value scale on it using the type of hatching you plan to use. (Overhand side of pencil shading vs tip of pencil shading for example.) You'll see how the texture effects each value, and you'll get a good idea of the values you can and can't create on the paper.
- Draw 5 to 10 one inch squares.
- Leave the first square blank.
- Make the last square (No. 10) as dark as you can without squashing the grain of the paper.
- Fill the square using the softest pencil first (4B to 9B) and then go over that with the sharp tip of a harder pencil (2H to HB).
(The harder lead will act like a "stump" and push the softer lead into the grain of the paper that it skipped over and make the value darker.)
- Repeat until the square is as dark as it can be without completely flattening the paper texture or grain.
- Gradate the middle squares into steps using a combination of pencils grades for each step.
- In other words, 2H, 3H,4H and 5H pencils won't easily create one stepped value each and you won't work like that anyway. Realistically, you'll use whatever pencil you have in hand to start shading and then switch to another to darken the value, so it's much more natural to create the steps with a combination of pencils too.
- Use the hard lead over soft lead technique for all of the darker values. For the lighter values, use the same technique only with a very light touch. For example, to make a "3" value, you might hatch a 4H pencil over a 3H.
- Here's a chart with pencil grades and their general value ranges. (Each brand is different though, so test your pencils to find their range.)
|Extremely Hard - 9H to 7H
||Very Hard - 6H to 5H
||Hard - 4H to 3H
|Medium Hard - 2H to H
||Medium - F to HB
||Medium Soft - B to 2B
|Soft - 3B to 4B
||Very Soft - 5B to 6B
||Extremely Soft - 7B to 9B
A Mid Gray and White Value Finder
In some circumstances values fool the eye. For example, look at the upper lower edges of the squares on the value scale. They look as if they lighten as they get nearer the darker value above them, and darker at the bottom where they approach the lighter value underneath.
That's an optical illusion.
Actually, those squares are solid gray. Surround any of them with a single value and you'll clearly see that.
A "value finder" is just a piece of paper with a hole cut in it that you can use to surround a questionable value with a known value.
Note: I call these "value finders." If they have a proper name, I don't know what it is. :)