Photo of charcoal portrait drawing and stick of charcoal

Enlarge your source photo to the same size as your charcoal drawing to check the proportions of the face.

Author: Sonia Reeder-Jones



Drawing From Reference Photos

Use This Simple Tool To Check Drawing Proportions

Measure A Feature On Your Source Photo
illustration showing measuring the face height within smaller source photo
Measure The Same Feature On Your Drawing
illustration showing measuring the face height within drawing

Enlarge your source photo by _____ to match the size of your drawing.

How To Check Your Drawing Proportions When Drawing Portraits From Photos:

When drawing from reference photos, my source photo is often smaller than my finished drawing. While drawing proportions of the face, if something seems off, I like to check proprtions. Here's a simple method.

  1. Use the tool above to find the percentage to enlarge
  2. Pick a main feature within your reference photo that's easy to measure like height of the face
  3. Measure the exact same feature on your drawing
  4. Enter the smaller of the two measurements into the first field
  5. Enter the larger of the two measurements into the second field
  6. Click the button to get the percentage to enlarge
  7. Print one enlarged photocopy of your reference photo
  8. Trace the enlarged copy onto plexiglass or transparent paper
  9. Overlay this tracing over your drawing and check your proportions
  10. Make corrections as needed and finish your drawing
image of charcoal drawing next to small source photo
image of photocopy of source photo next to tracing of photocopy on plexiglass

Here's The Math:

I pick a feature or section that's easy to measure. First I measure my reference photo. I measure the height of the face from bottom of chin to hairline for instance. Then I take the exact same measurement on my drawing.

(source photo) x = 3.5"
(drawing) y = 5"

5/3.5 = 1.428571428571429

Round up and move decimal 2 places to the right. This gives you the percentage to blow up your reference photo on a copy machine to match the size of your drawing. In the above example, I would enlarge my reference photo by 143% on a copy machine to match the size of my drawing.

I use a piece of plexiglass and a washable marker. I trace the outline and main features from my enlarged photocopy. Then I lay the plexiglass over my drawing and see what might be off.

image of tracing on plexiglass layed over top of drawing
image of tracing on plexiglass layed over top of drawing

This makes it easy to compare the drawing proportions to the traced features on the plexiglass. It's a rough outline, but enough to make a quick comparison and identify what might be off. It helps me make minor adjustments and check my proportions. Obviously I could make comparisons using Photoshop or photo editing software, but this works for me. I hope this tip helps you when drawing portrait proportions.

One final note about tracing onto plexiglass. If you happen to use a dry erase marker, you may find it difficult to clean the marker off of your plexiglass. Some sources suggest using alcohol to clean dry erase marker from plexiglass. Others suggest quickly tracing over the lines again with same marker and wiping off while wet. A Magic Eraser will take it off but it dulls and clouds up the surface of the plexiglass. I found it easiest to use a fine tip washable marker.