Analyzing Coin Edges: A Not So Simple Solution

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Author	Replies: 7 / Views: 2,824
austrokiwi Pillar of the Community 2087 Posts	Posted 04/14/2014 3:04 pm I collect Maria Theresa thalers(MTT). As its a generally obscure field I have to do my own research. MTTs more than any other coin , that I know of, a three sided. The edge of an MTT can reveal the mint and sometimes even the variety. Photographing the edge is easy but finding a means to analyse it so that any one else can repeat the work has been a pain. Some researchers convert the edge photo into a strip( in film days, here in Vienna, the university experts had the means to produce such photos. For the average collector the best method was measuring the length of the various devices and words on the edge. However for about five years I have thought an edge photo with a protractor might be the solution. I tried it in September last year( with my old Sony A 65 camera). I was disappointed. My efforts told me it would work. The big problem was photographing a transparent protractor was worse than photographing a coin. Today I tried again. I had to use completely indirect light ( bouncing it off walls) and a very long exposure(5 seconds), this is the result. The advantage of using degrees is that you don't have to ensure the image is 1-1 with the actual coin. All I need to find now is a clear plastic circular protractor(that is not as easy as one might think) The advantage is feature on the edge can be located or measured by degrees. Edited by austrokiwi 04/14/2014 4:31 pm Report this Post to the Staff

Pertinax Pillar of the Community United Kingdom 2133 Posts	Posted 04/14/2014 4:29 pm I used a clear plastic circular protractor in high school advanced maths and in university, so try appropriate suppliers. I doubt the learning of maths will have changed that much in this respect (even though it's 35 years). Report this Post to the Staff
CherreePicker Valued Member 440 Posts	Posted 04/14/2014 6:57 pm Could you cut out the center of the protractor so the edge (with the degrees) ran around the outside of the coin? Then you could directly photo the coin wiothout having to shoot through plastic. Report this Post to the Staff
austrokiwi Pillar of the Community 2087 Posts	Posted 04/15/2014 12:57 am Quote: Could you cut out the center of the protractor so the edge (with the degrees) ran around the outside of the coin? Then you could directly photo the coin wiothout having to shoot through plastic. The protractor and coin edge are photographed separately. The coin is placed inside a Flashlight reflector so that the edge becomes a ring a round the coin. Then in Photoshop I cut out the edge ring flip it so it is no longer a mirror image. For the protractor I "cut" out the center in editing and then placed the ring on the inside of the edge ring. I would like to place the protractor on the outside but to see all the edge features easily I placed it on the inside of the edge. A clear protractor may be easy to find in the USA but in Austria the kids seem to have a preference for colored protractors! Report this Post to the Staff
CherreePicker Valued Member 440 Posts	Posted 04/15/2014 06:08 am Neat idea. Could you post a pic of the components? Would like to try this with a bust half. Report this Post to the Staff
austrokiwi Pillar of the Community 2087 Posts	Posted 04/15/2014 07:43 am Not sure what you mean by components. Here is a picture of a thaler in the flash light reflector: These days its getting harder to find a suitable flash light. the LED Flash lights tend to have the wrong shaped reflector. I do not put the coin directly into the reflector I usually have it sitting on something like an Eraser( is that the correct word? in NZ we used to call them rubbers; for rubbing out) I found its best to get the edge reflection away from the coin as much as possible(and still get a picture of the complete edge. It is extremely difficult to get the edge lit adequately so I increase the exposure time. It tends to blow out the picture of the coin but it ensures the edge comes out clear. If you need more pictures of Components...please specify further what you are looking to see. Edited by austrokiwi 04/15/2014 07:45 am Report this Post to the Staff
CherreePicker Valued Member 440 Posts	Posted 04/15/2014 5:52 pm OK so you take a pic of the coin edge reflection circumferentially in the flashlight piece and then photoshop it down to size. Very neat idea. Report this Post to the Staff
Pertinax Pillar of the Community United Kingdom 2133 Posts	Posted 04/15/2014 6:32 pm You could order one from Amazon. See http://www.amazon.com/s/ref=nb_sb_s...20protractor Report this Post to the Staff
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