80/20 Cast Drawing

Article by Darren Rousar.

80/20 Cast Drawing80/20 cast drawing graphed out.
*Seeing relationships occurs throughout the cast drawing process. However, a few of the final things to check when finishing a drawing (or painting) are how well the observed relationships are represented.

Common in the world of business is a concept called the Pareto Principle, which is better known as the 80/20 Rule. Generally speaking, it states that roughly 80% of the results come from only 20% of the effort. The principle has been shown to be valid in a surprising number of fields including economics, athletics, and computer coding. Relative to learning to see, the 80/20 rule also applies to cast drawing.

Let’s take a look at how the concept applies to Mr. Gammell’s routine for cast drawing (which you may recall from the previous article, Mr. Gammell and the Cast).

There are six main stages of cast drawing:

  1. Finding the arabesque (the outline, contour, or potato shape)
  2. Finding the division between light and shadow (the bedbug line, shadow line, or terminator)
  3. Flatly massing-in the main shadow shapes
  4. Turning the bedbug line’s edge
  5. Representing value relationships (halftones)
  6. Representing edge relationships

As a student intent upon bringing your cast drawing to a fine finish, you will spend most of your easel time doing something not listed. But I’ll get to that in a moment.

80/20 Cast Drawing

From the list above, steps 1 and 2 are when most of your learning to see will occur. During those stages you are learning to see shape, relationships, and where light separates from shadow. We can briefly insert step 3 into this learning section, but only up to a point – a point I will also get to shortly.

As an aside, some define steps 1 and 2 as drawing and everything else as modeling.

Keeping with the 80/20 cast drawing concept, 80% of your learning will occur during steps 1 and 2, but they will take only 20% of the time you spend on a completed drawing.

In fact, until you can accurately do those first two steps, you have no business going down the list. Remember the art of starts?

Until you can accurately block-in a drawing, you have no business proceeding to finish.

Your teacher.

The Points of Step 3

Step 3, flatly massing-in the main shadow shapes, accomplishes two goals: helping you to better observe shapes, and beginning the process of value representation. That first one is why I mentioned step 3 earlier.

Nature is not outline. It is value shape against value shape and color note against color note. Therefore, a proper mass-in is the natural progression of a block-in, and in that sense visual learning is still on the rise.

In other words, you’re still still in the 20% range.


Needle Work

Needle work is the process of spending weeks using a dangerously sharp stick of charcoal to fill in all those little holes which are caused by the weave of the paper. This is what I meant in my first deferral, above.

Hyperbole aside (or not), as far as your learning curve goes needle work is deadly. Why? Just look at the graph at the top of the article. Needle work fills most of the 80% portion. You could say it’s 80% of the final 80% of a cast drawing.

Tightly toning the background of a white sheet of paper is not learning how to see. It is learning the skill of tightly toning the background of a white sheet of paper. Will that be a useful skill to have during your artistic career? I doubt it.

To be clear, I am not opposed to tightly rendered cast drawings. But they should be the summation of your cast drawing studies, not the rule.

A Caveat

Besides a tight finish there may be a reason for needling that might be worth your time – as long as you’ve first demonstrated accurate sight through accurate arabesques.


Needling darkens as well as smooths the area, and you might need that to achieve a broader range of value. Then again, odds are you’ll never get it as dark as nature.

Furthermore, seeing and representing the relationships between values are more important to your training.

A Better Rule

You’ll progress more quickly if you flip 80/20 cast drawing on its head. Spend 80% of your time perfecting your eye via steps 1 and 2, and only 20% of your time on the remaining steps. Then, once you’ve proved your eye through numerous cast starts, take one to finish.

Drawing with confidence.

You Can Draw With Confidence!

And you can begin today!

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You can learn cast drawing in Sight-Size at home!

Learning how to accurately see, as well as draw, is best done through cast drawing in Sight-Size. Ateliers exist worldwide to help you do that. But what if you cannot attend an atelier? Or, perhaps you're already in an atelier and would like to supplement that training? I can help.