During the last couple of years I have tried numerous ways of illustrating insulator embossings. At first I thought I could just photograph the skirts with the embossings. Then I quickly realized that the insulators were round, and photographs were flat. At close range the focus did not work and I couldn't read the sides.

I tried rotating video scans, graphite and grease-pencil rubbings. I tried rotating the skirt of the insulator on a photocopier in unison with the band of light as it crossed the glass. I tried rolling the skirts in chunks of colored plasticine and photocopying them. I was close to giving up completely. Then I discovered aluminum foil, white paint and white plasticine. 

Following are the 2 methods I found to the best.

Method #1
Line drawing on foil impressions.

For this method you will need to start with a strip of aluminum foil about a foot long, free from wrinkles. Next, apply flat white spray paint to the foil. Thin misty spraying sticks better than close range flooding. I use the dull side of the foil as it sticks better than the polished side. Lacquer-based sprays will dry in minutes but oil-based ones need to be left overnight. With long sharp scissors cut the foil in the shape of the embossing to be illustrated, but make it at least 1" larger all around. Next, hold the foil against the embossing area, painted side up. Press firmly against the foil with your thumb and fingers until you see impressions in the foil from the entire embossed area. Check for areas that got missed, like the crossbars on the "E", and the "A" crossbars, then release the foil from the glass. 

Gently stretch out the foil so that it is no longer curved, careful not to make any creases in it. Now take a very fine black felt pen and carefully draw on the raised areas left in the foil by embossing. Now it's off to the photocopier with the foil. There is a little room for error, because the impressions in the foil will be near exact. The only drawback I have found with this method is the unfamiliar way some markings look when only the highest point of the actual embossing has been illustrated. This is particularly noticeable with thick "prism" or "chisel point" embossings.

Method #2
The shadow profile.

I like this method the best. The technique requires the use of a good camera and critical lighting, so the trial-and-error process can be an expensive one.

First you will need white plasticine or modeling clay. It is available at art shops and some toy stores. I have found that FIMO clay does not work well. You will have to loosen up the plasticine first by working it with your hands. Roll the plasticine out into a slab of even thickness. Then roll the embossing portion you want to copy across the plasticine slab. Be sure to use even pressure as you roll or you will have a slight change in slab thickness. This would be noticed during the photography stage.

If you want an actual size reproduction of your embossing, you will have to size the region of the slab you photograph according to the size of print you expect to have made from your negative. I get 4 x 6 prints made, so I place a 6 inch ruler to one side of the embossing on the slab, then I adjust the distance form my camera until the ruler just fits in my view finder while in focus.

Magnified side view of the plasticine slab with embossing impression

The angle of lighting is very important in order to cast a shadow across the impression left in the plasticine. The light source needs to be just slightly higher than the plasticine. The trick is to illuminate the far edge of the impression and cast a shadow off the edges nearest to the light source. I use the top right corner as a point of source for the light. This illuminates all the opposite areas: the bottoms and left sides of the impressions. 

As you will see, the impression left in the plasticine is now backwards. When you get your film processed, you will have to remember to get these shots printed backwards. This is an odd request, but I have had no problem getting the camera shops to oblige.