Arrange three props on a middle tone (meaning a middle tone backdrop) and light them with standard lighting.

1. Squint with both eyes, then try it with one eye closed. Use whichever way works best for you.

Much depends on how we actually squint. How much we narrow our eyes governs how we see.

2. Observe the setup while gradually narrowing your eyes. As you narrow them more, notice how the tones darken, edges blur, colors dim and minor details dissolve—but notice also how areas of tone, though darker, become a bit easier to distinguish. Observe carefully and you will see.

3. Observe parts of the setup without squinting and then squint. Alternate between the two until you’re certain you see areas of tone a bit more clearly when squinting.

4. Narrow your eyes to the point just before your setup disappears into darkness—where everything is blurry, murky and dark—but look carefully! With a little imagination, you can organize everything you see into three tones.

Yes, they’re too dark but you can see the light, middle, and dark ranges of the setup.

Note: You’ve narrowed yours eyes correctly when you see dark sides of objects and their shadows merge to become larger masses.

5. Shut your eyes completely, then gradually open them to where you see exactly what you saw on the last step.

Now begin with eyes open, then narrow them until you see exactly what you saw before.

Arrange a new setup on a middle tone backdrop.

6. Squint to the extreme and see the setup in three tones.

7. Select an interesting area of the room and squint to the extreme until you see the entire area in just three tones.