I decided to play around with lighting coins for photos again this weekend so I brought home a few of my favorite subjects for reshoots. Some may recall that I kept my coins in red flocked trays for several years before moving them into paper envelopes. Tonight's experience proves that I really need to clean coins before shooting. Look at the tiny red fibers from those trays. The two cropped sections show the full size of the image as shot. Both have fibers but the one of the shield has at least twenty. True, you can't see them at a normal size but I really need to use a camel hair brush to sweep coins before shooting. I'll be shooting this coin again over the next three days. I wonder if I can get a 'clean' one. It will take years for me to escape the residue of the red flocked trays I liked so much.
If money is not an object, I have used a static master brush for many years, The polonium strip needs to be replaced over time, but it really gets rid of dust and small fibers. http://www.amazon.com/Static-Master-Brush-1-Inch/dp/B0000AE67S And if you ever get some real enemies, polonium can kill if inserted into the body, see "Alexander Litvinenko" assassination.
For nothing as I am a begninner and you certainly know far better than me, but don't I see bumbs or the pearls here on the coin which means it is a cast?? Look at the yellow markers:
What I see is small beads of foreign material on the surface. I'll need to get out the microscope to be sure but I have seen plastic pellet residue from coins tumbled as part of cleaning and tiny flakes of Ren-Wax which is a lot easier to put on a coin than it is to take off.
When I photograph raw coins, I use a puff of canned air to blow them off. I give them another puff before I put them into their holders. I'm assuming that would fix your red thread problem, and is really cheap.
Many coins, particularly bronzes, have a slight tackiness (feel, not look... although some might be considered visually tacky as well ). Perhaps this is from prior cleaning or treatment-- waxes, Verdicare, oil, whatever. A puff of air doesn't dislodge the fine debris. Usually I don't notice until processing the images. If there are just one or two little specks, I use the Photoshop spot healing brush. If extensive, I give the coin a quick swish in acetone, dry with a lint-free cloth, and rephotograph.
My brush works on most but I still have to remember to do it. The percentage of coins being treated with waxes and oils continues to increase. Some of the treatments, storage and cleaning methods don't get tacky for years after exposure. This is all to be expected from coins. We have no idea where these things have been.
