Thursday, July 31, 2008

On the expenses of photographing a coin

I recently suggested that boxes of junk coins could be photographed at close to zero cost but it might average an hour to enter a coin into a database. Nathan T. Elkins replied
... it is time consuming and expensive to photograph finds and, from my own experience, I can say it is often easier to identify and enter a coin in a database than to properly photograph it. These online databases simply do not have the funding to hire someone to enter the photographs into a database.

How much does it cost to photograph a coin and how can this be reduced?

The ANS charges twenty bucks per coin (both sides). They have a highly skilled staff photographer, Alan Roche, who has a degree in photography and is capable of producing beautiful pictures suitable for glossy annual reports sent to donors.

I'm not talking about those kind of photographs.

To document the basement boxes the biggest expense may not be the camera operator but security. The ANS learned this when Sheldon (the large cent expert and psychologist) demonstrated his deep understanding of kleptomania doing swicheroo thefts from the ANS's trays. I photographed a few coins at the ANS last year and they watched me like a hawk!

I'd like to propose the use of glove boxes to deal with the security issue. Trusted guards can place coins in the glove box and untrusted photographers can manipulate them with very low risk.

We can further reduce the cost by eliminating the camera operator. If we don't worry about orientation or correct lighting coins can be dumped into a hopper and photographed as they ride a conveyer belt. This may seem dumb, but we don't need correct orientation to document a coin for theft, or later restoration, or automatic computer classification. It may even be possible for computers to make very good guesses and orient the images later. Lighting is important, but if we can reduce the cost of taking a single coin image to near-zero then lighting angles can be handled by taking six pictures, using six different light sources, also for near-zero cost.

(Taking multiple pictures of coins under good lighting is a good idea anyway. When buying a coin in person most collectors tilt the coin -- the motion changing the lighting and revealing details. If I buy clothing online most catalogs let me rotate the garment but coin dealer sites don't....)

Perhaps in the future computers will be able to take better pictures of ancient coins than the best human experts? Far-fetched, but this is already the case for ancient cuneiform tablets! Check out the pictures in this paper by Sean Eron Anderson and Marc Levoy.

1 comment:

Jim said...

Coins can be mass-scanned carefully about 20 coins at a shot on a flatbed scanner. I have owned 2 flatbed scanners and I developed a mass-scanning method. My current scanner is 8.5x12 inches. I took a 8.5x11 sheet of greeting card stock paper and cut 20 square holes in it that are 1.75 inches in size. The scan ends up having 20 coins that are about the same dimensions as a 2x2 flip visually. I usually make the scan at 300, 600 or 1000 DPI and then individually cut and paste each one out.

So one big obverse scan and one big reverse scan. The only drawback is that the initial scan of a whole bed of coins at a high DPI does take time but the more RAM your computer has, the quicker it seems to go.

It also goes faster if you use a less memory hogging software program such as Irfanview rather than one like Photoshop.

There is absolutely no need to roll out a Hasselblad or even a Canon Rebel to photograph every coin, especially when we are talking low value or low grade coins.