Every now and then you may have heard the comment, “Do as I say, not as I do.” The intent, of course, is to get you to do something that the speaker might not normally do. And so it is with the Isolator. It’s not normally part of my artistic kit. Nevertheless I have on occasion recommended it to my students.
What is the Isolator?
There are a few versions but most are like those shown in the images for this article: a small rectangle of cardboard with two holes cut into it. Some artists use two paper towel rolls instead (with one for each eye), but in my opinion those show too wide a view.
Regardless of the style, the main idea is to block your view of everything except what you see through the holes.
To use one, you simply stand in your viewing position and hold the Isolator out. Shift it about so that you have one hole over your artwork and the other over the same place on your subject.* Pushing it away or pulling it closer to your eye also allows you to control those positions as well as how large of an area is viewable.
Why Use an Isolator?
The Isolator is used to compare the values and/or color notes of isolated areas on your artwork and subject. Notice that I did not say comparing value and color note relationships.
For an artist interested in seeing the visual impression, there is little reason to use one. Why? Because it does what it says: it isolates. And isolation is death to the big-look. Through it you only see a small part of your subject, completely independent of its surroundings. This means that the adjustments your eye normally makes relative to those surrounding the area in question are effectively null.
As a student, it’s better to learn how to see the whole rather than make it up from the parts.
But Why Not?
Though you can’t use it to see accurate value and color note relationships, you may be able use it to see whether your attempt matches nature. Your eye will not adjust the isolated area to the surroundings of your artwork nor your subject.
Is that bad? I think yes and no. Just like it’s better to learn to see the whole, it is also better to learn to see how close your attempts are to your source with your eye alone. The Isolator, therefore, can become a shortcut that teaches your eye nothing.
Then again, I do occasionally recommend one to my online students. Why? Because I’m not in the room with them.
When we’re in a physical atelier I can mass-in accurate values and color notes directly on the student’s work. Doing so gives them an additional target and shows them the process on something they are actually working on themselves.
Online none of that is possible. As such the Isolator is a stand-in for my eye.
Should You Use One?
To answer this question I send you back to the Guess and Check article. First, do your best to see and record an accurate value or color note, relative to the whole. Then, if in doubt resort to the Isolator to check your attempt.
Finally, before making any correction via the Isolator use your eye alone and try to see if you can observe the same value or color without it.
* Note that the way I show it in the image at the top of the article is simply to show the Isolator itself. The views through the holes show completely different sections of the setup.