The bulb burned out in my studio light for coin photography. I have always used tungsten lights as they are well known to cameras and imaging software so can easily be corrected for to get accurate color.
But knowing that they are no longer produced, I decided to try and make the jump to a more modern light bulb. Ha! Been fighting all day with this Philips 10.5W LED 2700K bulb that is supposed to more or less mimic to soft color tones of tungsten. But all I get are yellow coins.
I will be changing bulbs depending on what I have here and what I might buy tomorrow, and using this rather nice RPM Kennedy as my test coin. It is a nice shiny MS grade coin and I plan on puttering around with the light source until I can make it look like it looks in hand.
Also of note, just having that light on in the backgrond when I shot the mint mark photo under the scope put a strong copper/yellow reflection along the edge of the branch, so it buggered up both full coin and close up photos.
The plan is to re-post more images of this coin in this thread once I change bulbs.
1964-D
Kennedy half dollar RPM-002, FS-502
The first try at another bulb is waaaay better. This is a 72W 2900K halogen. Photos looked pretty close using auto white balance in the camera but jumped to almost right on with Photoshop's "auto color" correct. Shows that it is much easier to work with a light source that the software can deal with. My only problem here is that the bulb is very bright and hard to get the luster quite right, although possibly upping the f-stop would both fix that and give a stronger depth of field.
With reasonable success on the Kennedy, I wanted to test a Lincoln with the halogen as well. Same deal, with an auto color correct in Photoshop pretty much nailing it. I found this RPM a couple days ago and hadn't put it in the 2x2 yet so made for a spiffy test coin. Coin is toned pretty much as the photos show with just that overly yellow glare spot at the top of the head being out of whack.
1969-S/S
Lincoln Memorial cent 1MM-008 (west)
Didn't want to quit until I gave LED another shot. This time I dropped in a 60W 5000K bulb and the world turned blue. So unless you like yellow or blue coins so far I don't have a good choice for an LED bulb. Thinking to go with the halogen since it does the job and maybe do some minor tinkering/changing to see if I can nail it down even better over the next couple days.
Here is the test coin under the 60W LED (color corrected, it was far more blue originally)
And since it is easiest to see what is going on in a side by side, here are the final results of my three bulb test. I think the choice is obvious.
Posted 10/24/2018 10:45 pm
