It’s best to begin manipulating key after you know how to shade reasonably well but want more control. There are several reasons why you need to know how to control value.
Alter key to:
- Express mood
- Balance the composition
- Create a focus
- Indicate color differences in gray scale
To alter the key of a drawing in a realistic way, keep the values the same number of steps apart on the scale (gray scale), or nearly so. There’s always a little wiggle room available for artistic interpretation though.
Change the Key Of A Reference Photo
Alter a reference photo’s key in a photo editing program by adjusting the contrast to alter all the values at the same time, or use “curves” to alter shadows, mid tones, and highlights, separately.
Here are some instructions for Photoshop, but the controls should be similar in all image editing programs.
Always make a copy of the image, and work from the saved copy.
How To Adjust Contrast In Photoshop
1. Image > Adjustments > Brightness / Contrast
2. The Brightness slide makes the entire image brighter or darker.
3. The Contrast slide evens out the values at one extreme (think mud), and separates the lights from the darks by many degrees at the other extreme (think posterized).
Sometimes a small adjustment with one of these sliders is all it takes to make a good reference photo into a great one.
How To Adjust With Curves In Photoshop
1. Image > Adjustments > Curves
2. You’ll see an angled line over a grid.
3. One end on the line controls the darks, the other end controls the lights, and the middle part controls the middle values. Grab one end or the other and see what happens. (You can always put it back the way it was.) Grab the middle and bend the line into a curve, first one way and then the other, and watch what happens. (Your eyes should be sparkling with glee at the possibilities about now.)
I usually lighten the darks or the mid-values, but sometimes I lighten the highlights too if I want the image to have a contrast-y sparkle and punch.
Change the Key After The Drawing Is Done
It’s easy enough to darken values by hatching over them, but lightening them can be tricky. I try not to get into that situation by building the values slowly so I can sense what’s needed and change them as the whole drawing evolves. Art is always unpredictable though, so here are a few techniques that might work for you if you have to lighten.
1. Pinch a kneaded eraser into a big rounded shape and gently tap the area until it lightens evenly. Some people like to roll the eraser in a log shape and then roll it across the area. Either way, you’ll have to touch up after you’re done. In particular, the darkest shadows usually lighten too much and need to be re-darkened.
2. Use a clean flat brush to “lift” graphite from very dark areas. Gently flick it across the dark area and the bristles will lift and remove the graphite.
3. If area is already on the light side but needs to be even lighter, try dabbing it with a clean chamois cloth. Graphite smears easily so dab, roll, and lift — don’t pull and drag or it will smudge.
The Big IT
Value is the “IT” for graphite artists. We have to do everything with it, from creating textures to indicating mood. Your own artistic sense will give you clues about what a drawing needs, so listen closely to inner prompts and act on them. If you do, somewhere along the way you’ll learn to trust yourself and build a more surefooted and agile drawing technique.
Gray Scale Inspiration
For inspiration and ideas about how to effectively use key, look at photos by Ansel Adams, classic black and white movies, or any artwork by J. D. Hillberry and Mike Sibley.
Here’s a link to part one of this piece.
