Question from a friend regarding gold coins that look "bronze" in images...

[James_OldeTowne]

I am posting this for a friend who asked me to do so. He wants to image a bunch of gold coins, and believes the color looks "bronzed", rather than normal gold. The problem is not occurring with copper or silver coins, and coins are in PCGS and NGC holders. Any help would be appreciated.

 

Here are the specifics:

 

- camera = nikon E300

- 108 mm lens

- single halogen light, a "Halogen 1000"

- he is using a light diffuser

 

I will print out any and all responses.

 

Thanks in advance!

[bsshog40]

I don't know much about a nikon James but it sounds like the camera may not have enough exposure. I know that when I take pics with my canon on auto that it will adjust itself for the lighting. I always take my coin pics in the manual mode so that I can set my own exposure, lighting, and color settings. This is the only gold I have but this is the color I come out with. My lighting was a little off center but the exposure was set pretty decent to get the right look of the coin.

[robec1347]

He might need to adjust his white balance for use with a halogen light. It could also be the position of the lights as in elevation.

[Oldtrader3]

The halogen light is too hot use cooler lighting.

[Conder101]

My lighting was a little off center but the exposure was set pretty decent to get the right look of the coin.

Looks like silver.

[BillJones]

The hallolgin light is so intense that it washed out all of the color.

 

When I first started to learn coin photography the guy at the photo shop, who was very helpful otherwise, steered me toward a pair of very bright, intense lights for use with a copy stand. It just didn't work out. Only the large items came out decently. The small items, which included most coins, were over exposed.

[bsshog40]

My lighting was a little off center but the exposure was set pretty decent to get the right look of the coin.

Looks like silver.

 

Come on Conder! That's gold, maybe your monitor is too bright? I do see what looks like a little silver color on the edges but that's where my lights were a little off center and was too bright on that side.

[pendragon1998]

The exposure, lighting angle, and age and composition of the gold will play roles in the images he gets.

 

These images were both taken under the exact same lighting, with the only differences being slight changes in lighting angle and exposure. IIRC, I was using 1 or 2 60 W 'natural' incandescent bulbs and an axial lighting setup. As you can see, the two gold coins show a significant difference in color and appearance, only part of which is due to the lighting (the two coins varied considerably in their color and finish to begin with).

 

1975 Commonwealth of the Bahamas $50

.917 Au (0.0804 oz Au) - KM# 69

 

1945 Mexico 2 Pesos

.900 Au (0.0482 oz Au) - KM# 461

[robec1347]

These coins belong to Rey. Both coins were taken under two 13 watt OTT light. The difference in color is due to the difference in light elevation. If I would have corrected the white balance during those shots, there would more than likely be no difference in color. I still believe that a correction in white balance would solve the problem, unless of course the light is burning a hole in the gold.

 

The composition of each coin is the same, 90% gold and 10% copper

 

 

 

[Conder101]

Come on Conder! That's gold, maybe your monitor is too bright?

Maybe so, but Robec1347's images look like gold, bsshog40's looks like silver (I know it's gold but it doesn't look like it.) Pendragon's second image also looks like gold. That's why I don't any serious judgements on coins based on computer images. There is considerable uncertainty as to whether the coin actually looks like the image.

[bsshog40]

Come on Conder! That's gold, maybe your monitor is too bright?

Maybe so, but Robec1347's images look like gold, bsshog40's looks like silver (I know it's gold but it doesn't look like it.) Pendragon's second image also looks like gold. That's why I don't any serious judgements on coins based on computer images. There is considerable uncertainty as to whether the coin actually looks like the image.

I know, I just don't have enough gold to practice with! I'm not in Bob and them's league yet!

[James_OldeTowne]

Thanks everyone. I printed this out and passed it along.

[MikeInFL]

I am posting this for a friend who asked me to do so. He wants to image a bunch of gold coins, and believes the color looks "bronzed", rather than normal gold.

 

I'll wager that either (a) his white balance is off due to the "warm" halogen light, and/or (b) he's blowing the red channel in his photographs. Both can and will cause the problems you describe.

 

If it is (a) then simpily buying a more color-balanced bulb (like a Reveal or Ott Light) will help -- but the best way to solve the problem is to buy a greycard and either doing a custom in-camera white balance or correcting the color cast in post processing.

 

If it is (b) then lowering the exposure followed by a boost on the low end in post processing will solve it.

 

If you post an example, I should be able to tell which is the problem in a few seconds.

 

Hope this helps (and it's not too late)...Mike

[MikeInFL]

p.s. are you sure it's not a "Olympus E300" -- Nikon doesn't make an E300 (they make a D300, which I own).