Measuring Techniques for Portrait Drawing

Let's take a look at two different approaches to achieving proportion in a portrait drawing. We'll call them Sight-Size Measuring (or direct measurements) and Comparative Measuring (or angles and relationships.) You'll learn about the differences between the two, when they're best used, and what their strengths and weaknesses are.

First, let's define them.

Both of the following techniques are covered in Portrait Drawing in Graphite & Charcoal 6 Week Course.

Sight-Size Measuring: Direct Measurements

Sight-size measuring refers to the process of taking literal height, width, and diagonal measurements of a 2D reference or from a single point of view when working from life. This is a pretty straight forward approach when working from a photo, drawing, or other flat reference, but can get a little complicated when working from life because there are many more variables.

When working from a photo, you must have it printed at the same size that you want the finished art: no reducing or enlarging. Then you'll use one of a variety of techniques (some people use a pencil, others thread, while I prefer dividers) to transfer measurements to your paper. You can triangulate from different points to double check accuracy as you go.

While I won't get into detail here about how to work sight-size from life (that's an entire course in itself), it is very similar to working from flat references but requires a controlled environment. You and your subject must both remain in the same place, your posture must be consistent, and your measuring technique steady or else dimensions will constantly be in flux.

Comparative Measuring: Angles and Relationships

When using comparative measuring techniques, you may take hight and width measurements as well as angles and horizontal and vertical comparisons, but you might not be translating them at the same scale. The idea is that you would instead be making a relative comparison.

For example, with sight-size you would measuring that the width is X wide, and the height is X high. With comparative measuring you'd compare the height and width, and determine that the height is about 1.5x the width, and just make sure that your drawing is also 1.5x as tall as it is wide. It could be larger or smaller than your reference, so long as that relationship is correct.

My favorite way to make these comparative measurements is to assess the angles. Theoretically, if all the angles are correct, you could have any scale and the drawing would be perfect! However, that's just theoretical, and us humans tend to not be perfect. So, you can use comparative height and width measurements as well as other comparisons to double check angles.

This method is much more flexible and doesn't require such a controlled set-up to achieve.

The Pros and Cons of These Measuring Techniques

Sight-Size Pros and Cons

(A graphite portrait drawing done using the sight-size method.)

On the positive side, sight-size achieves accuracy easier than other methods. This is great for artists who are just beginning or are still training their eye for proportion.

It's also very good for people who are trying to teach themselves, because figuring out where you're off is a matter of taking more measurements and can be done without the 'fresh eyes' of a mentor. Either it measures out or it doesn't!

The high level of accuracy potential also makes this a great approach when you're working on a commissioned portrait or other subject that requires correct proportions. It's also a good approach when you're working with media that doesn't allow for a lot of corrections, like graphite or watercolor. This is why we use this method when working in graphite in Portrait Drawing in Graphite & Charcoal.

Cons of sight-size are that it works only in limited situations: Where your 2D reference is the same size as you want the result, or if working from life where your model can remain still for extended periods of time and you can work as close as you wish to them, and where lighting and the environment will star the same. It's a very time consuming method that requires control and consistency, and becomes useless when you're trying to, say, sketch an animal at the zoo or a wiggly impatient child.

Comparative Measuring Pros and Cons

(A charcoal portrait drawing done using comparative measurements and angles.)

One big strong point of using comparisons is that it's adaptable to pretty much any situation: any reference and any live model can be assessed and drawn at any scale using angles and relative measurements. The process goes much faster, is more dynamic, and is more useful with the ebbs and flows of time and life as it unfolds during a drawing.

This is a great method for people who are impatient with tedious measurements, secure with making adjustments later in the process, and in situations where you must move more quickly, like in a life drawing session. It also allows you to scale up from a reference, or down.

It also creates a more dynamic drawing and tends to show more life and movement compared to a stiff, finite sight-size drawing.

Cons to this method are that it's not as accurate and requires a trained eye to make refinements to those first guesses. It works better for artists who have a little more experience breaking down forms abstractly and is more challenging for those who are new to drawing and proportion. It's less literal, and therefore more difficult to understand.

Which One is Best for Me?

This will depend a lot on your personality. I like to present both of these methods in Portrait Drawing in Graphite & Charcoal because after two decades of teaching, I have found that some students absolutely love sight-size, and those same students are usually not as fond of comparative measuring, and vice versa. I think it all has to do with how we naturally solve problems in general, and the types of ideas we are most attracted to.

Conversely, I find that the method a student dislikes is usually their best "cross-training." Often someone who likes comparative measuring will lack the patience to really perfect their drawing, while the sight-size fan has difficulty letting loose and trusting themselves. Each benefits greatly by practicing the other technique.

My suggestion is to try both, delve deeper into practicing the one you enjoy the most, and when you hit a plateau hope over to the other method for some cross training. You'll find when you return to your preferred method, you will have progressed.

I hope this article has proven helpful to you!

If you'd like to learn more, check out the six lesson, multi-demonstration video course below, or check the calendar to see if it's coming up live.