You have a great photo you took and you need to scale it up to a reasonable size for a drawing before you start  to paint. Free-hand sketching on the canvas doesn't cut the mustard as there is too much detail or you need to be more accurate to get the results you are after. Using the grid method works but can be time-consuming jumping backwards and forwards measuring up and down the grid lines. That's where the Accurasee Proportional Divider comes in as a great time-saving tool but more importantly an essential piece of equipment to make sure the proportions are spot on making your sketch an exact reproduction of your photo.

What I would like to do with this post is walk you through the way I use a Accurasee proportional divider. You will also discover just how useful this tool is. It is all about transferring scale. The proportional divider has two ends, a small end and a large end. Most also have a mechanism for altering the ratio between the two ends. You align your subject up in the small end of the tool and transfer the spacing of the large end to your drawing. It is truly that easy, taking the guess work out of free-hand drawing.

How to scale a drawing using an Accurasee proportional divider

To explain in more detail here are some simple steps to follow.

  1. If you are transferring scales from a true-life subject matter and not from a photo, hold the proportional divider at arm's length in front of your subject matter. Otherwise just use the divider directly against your photo.
  2. Use the small end of the divider to gauge the height or width of a key dimension of your subject matter.
  3. Using the larger end if the divider, transfer the scaled up dimension onto your drawing surface.
  4. Repeat the same process until you have enough reference points so your sketch represents your subject matter correctly.
  5. To change the size of your drawing, simply change the location of the pivot point. The divider I am using is a accurasee proportional divider which has a red tab for adjusting the scale. The closer you move the pivot point to the small side the larger scale your sketch will be.
  6. I also use the divider during painting just as a final check to make sure my proportions remain correct.

There are a various types proportional dividers to choose from. You can usually pick them up from an architectural and drafting supplies stores, marine navigation equipment or some specialized arts and craft suppliers.

As I stated before, I used the Accurasee proportional divider for this post. Being made of plastic it does tend to bend a bit and distort the scales slightly. However if you are starting out this a nice inexpensive entry point. My divider of choose is a marine navigation proportional divider from Weems & Plath. I purchased it online, for me it is an ultimate precision tool, giving me the accuracy needed to transfer scales down to the finest detail.

Useful resources

Here is a list of proportional dividers I have found available for purchase online.