Use of light for photographic porous coins

[ccg]

I've found that pieces that do not have a completely smooth surface (e.g. modern coins) in high grade (especially with lusture) can be best shot using a strong florescent light.

 

Here's an example of a Philip I ant: the original picture (natural light), and the second picture (florescent light)

 

[Art]

Nice info.

[thedeadpoint]

Wow, they look like completely different coins. This would be a great thread for a coin photography subforum.

[SMS]

Which coin and background most closely resembles the original? And what metal is that supposed to be? There are a number of things that may affect the color of a photo. I noticed that the background even among the two florescent photos differs. The focus and rotation are different between the natural light and florescent photos, as well as either the position of the light source or vertical position of the camera itself.

 

I'm curious to see the first set of photos again with better focus and the light source a bit more centered, maybe?

 

Albeit, still nice photos.

[ccg]

It's mid-grade silver, and the coin by modern grading would be called "BU".

 

Focus setting was the same for all pics.

 

As for the one best resembling the original, lower left.

[hiho]

Interesting comparison. And as lighting is always the hardest part of photographing coins properly, this is very useful information. Thanks!

[Russel]

First of all, I want to say that I'm not trying to criticize anyone. My intention is to help point out ways to improve coin photography. I'm going a little off topic with this thread (the subject of my post is white balance) because I think it will help some of us to better understand one important aspect of digital photography.

 

I also want to say that I wish I had a coin like this one! Very nice!

 

 

I've found that pieces that do not have a completely smooth surface (e.g. modern coins) in high grade (especially with lusture) can be best shot using a strong florescent light.

 

Here's an example of a Philip I ant: the original picture (natural light), and the second picture (florescent light)

 

 

One aspect of digital photography that requires careful attention is white balance. If the white balance is off, the colors will appear off. I notice digital photographs quite often that have a brownish cast to them. That is what can happen if your camera has the white balance calibrated to sunlight and the light source for the photograph is incandescent light.

 

Notice the difference in the background color of the photographs take with florescent light (the two lower photographs) There is a slight shift in white balance between them. The white balance isn't too far off in the florescent light photograph, that is why it looks more like gold rather than copper. If you look at the histogram for each color element of the photographs with florescent lighting you can see how the peaks in color information line up.

 

If you look at the photographs taken in natural light, you can see that the color information peaks don't line up. That is a good indicator that the white balance setting was not correct for photographs taken in natural light.

 

 

Histogram for upper photographs taken in natural light (white balance is off)

Notice the tallest peaks don't line up.

 

 

Histogram for lower photographs taken in florescent light (white balance is good)

Notice the tallest peaks do line up

 

In any event, be sure to check that the white balance of your digital camera is set correctly for the type of light you are using. Many digital cameras these days allow you to calibrate the white balance for the light you are using by taking a photograph of a white or 18% grey card. If the digital camera doesn't have such a calibration mode, there is usually a preset you can choose for the type of light you are using to photograph with, such as Daylight, Daylight - cloudy, shade, florescent, incandescent, etc.

 

Here are some examples of what white balance can do:

 

This was taken with sunlight with cloud cover and the correct white balance (about 5000°K):

 

 

This is the same photograph with white balance set incorrectly for florescent light (4100°K):

 

 

And just for fun, with white balance incorrectly set for incadescent (3100°K):

[ccg]

Wow, great info!