Prospek Proportion Tool
For years I've wanted to find something like the Prospek Proportion Divider. Two sticks with a movable hinge that I can set to reduce or enlarge an image. This helps so much when either drawing from life or a photo that I'd call it the most essential proportion tool you can get.
The problem is, a good one comes in aluminum or some other metal and costs over $100 anywhere drafting tools are sold with a really good range. Some places don't even carry the expensive ones. Jerry's Artarama has one of the nice metal ones for $99.99 listed as Proportional Divider.
I've looked at that, wished I had it, had trouble justifying the cost and gone back to using my fingers or a ruler to measure and calculate proportions between a reference and my drawing's tick marks. What I didn't know was that Jerry's Artarama also carries the Prospek.
It's the same tool for $8.09 at Jerry's regular price.
Yeah. The $100 major useful tool for getting proportions right just dropped to less than a tenth of that because it's molded in sturdy hard red plastic instead of crafted in metal. The join is a handy little plastic tab that just snaps out.
To change the proportions, you pull the little tab back to the side, away from the end that's forked. It comes off easily. Pull the peg off both sides and insert it into another hole - count the same number of holes on both pieces.
Push the peg through your selected hole and slide the white plastic holder over it again till it snaps. Make sure that little ridge is sticking up and you can push it till the peg snaps into the far end of the notch. Then it's solid.
It doesn't have the precise range of adjustments as the $99.99 metal tool but on the other hand, you can afford the Prospek no matter what your budget is.
I bought one and I'm excited, because it works just as well as the fancier ones do. It's lasted through an interstate move and a number of rough situations since then. I've stepped on it without breaking it - don't try this at home, but it did survive one accident already. So this tool is sturdier than you'd expect from the cheap plastic version of a drafting tool.
Beginners especially will benefit from being able to use this to measure photo references whether they're on screen or on paper.
Using the Prospek proportion tool
If you want to enlarge a small reference, move the legs till the small end of the X shaped tool is just touching the dimension you want to measure - say, the width of a head. Adjust it while it's on the reference. You can also do the same thing at arm's length holding it in front of you to look at a live model or static object you're drawing from life - as long as you don't move, the length of your arm is consistent and you'll get accurate relative proportions.
Without moving the legs, turn the X shaped Prospek so that the wide end is on your paper. Make tick marks where the points fall. This also lets you place your reference on the page easier - the proportion remains consistent wherever you put the wide end of the Prospek so you can decide to move the head farther from the edge of the paper or make it off center easier.
The legs move easily and stay at the same proportion once moved unless you move them again. Friction holds them firmly in place no matter how many times I use this little handy tool.
If you want to reduce a large subject, just reverse the process. Use the wide end of the tool to measure your object and the smaller end to make your tick marks on the paper. Once you have the tick marks in place, connect the dots with a freehand line.
You can make as many measurements as you need to accurately convey the details of a subject. I only do several when I draw something familiar like a face or a cat's face, but when I was a beginner I measured and enlarged with several hundred tick marks so that my drawing looked like a "connect the dots" puzzle in order to get total accuracy to the photo.
If you don't like the proportion you get, readjust the Prospek so that it enlarges a little less. The last opening toward the center will give you direct 1:1 proportions, useful if you're doing something from a life sized photo reference.
The Prospek proportion tool is incredibly easy to use and maintain. I recommend it for every artist, beginner to expert. It just makes life easy and proportions accurate with a lot less work than measuring with a ruler and doing arithmetic for every measured proportion. Unlike the grid method it doesn't leave marks that need erasing.
I've found that if I keep it at the same angle on the reference and the drawing, I can even keep relative angles accurate - like the angle between the eyes in a face that's tilted. That takes a little practice but it's well worth using it for angles as well. You just need to remember to pay attention to the angle and keep it tilted the same amount when transferring to the paper.
So the next time you shop at Jerry's for any of your supplies, search on the Prospek and add it to your order. Your drawings will become a lot more accurate and won't take nearly as long for good measurements using this inexpensive, wonderful tool.
Alternative Proportion Tools
Dick Blick carries a couple of alternative proportion tools - an Alvin hardwood Pantograph for under $30 allows exact copying from a flat surface and the demonstration photo shows proportional copying. This is a little more complex to use, the drawing lead is inserted in the tool so you're necessarily marking with graphite rather than directly with your oil pastels. Some may find the Pantograph more useful, since you can trace the entire line rather than just physically calculating tick marks.
Dick Blick also has a proportion wheel that I used frequently with my ruler before I was able to get the Prospek. This is another alternative to measuring - just check the width in units on your ruler, turn the proportion wheel to your desired enlargement and read off the new numbers to place tick marks on your paper.
I found the Prospek speeds the process and is a lot easier to handle than either of these tools though. It's your choice what type of mechanical aid if any you want for enlargements and reductions. My choice is the Prospek - and maybe someday I'll invest in that nice metal one for $99.99 since it allows finer size adjustments. So far the Prospek works fine for me.