Photographing proof coins with color

OriginalDan · March 15, 2012 9:23AM

I'm calling on some of you photo experts for some help here. I'm on a quest to shoot really dynamite coin photos and I've run up against a roadblock trying to shoot this proof trade dollar. It's a fantastic coin and I'd love to nail the color. Here's where I'm at right now:

(please ignore the slab defects, I'll polish those out later)

My setup:
I'm shooting with a 90mm equivalent macro lens, a single diffused light source perpendicular to a slab which is tilted slightly with respect to the lens. The single diffused light is a Jansjo LED light, diffused with double ply diffusor paper. The light works great for regular coin photos.

As you can see, the issue I'm having is with the light source reflecting off of the face of the slab. Should I...

1. Move the camera higher, allowing me to back of the light source so that it covers more than the size of the coin, allowing me to play with the overall contrast of the coin and "contrast out" the glare?
2. Use a better/different light source?
3. ???

Would love to hear your thoughts on how to improve my shots of proof coins with color. Thanks in advance.

Edit: Yes, I have Mark's book and apparently I need some independent tutoring

AnkurJ · March 15, 2012 9:27AM

Have to use Axial lighting. I've tried and failed.

OriginalDan · March 15, 2012 9:33AM

I found axial lighting to be an exercise in frustration. Maybe I need to keep trying. According to Mark's book, you don't *have* to use axial lighting. It should be possible to do it using the tilt method with coin and light source perpendicular. On that note, I think another possible issue is that my light source and slab face aren't completely perpendicular.

Here's another example of a proof-like reverse. I feel like it's almost there, I think my next step will be to back off the camera and light distance a bit and check the slab/light angle.

AnkurJ · March 15, 2012 10:34AM

I know Mark used to do two images for proofs. One to show the color and one the mirror surfaces. I'm not sure if there is a way to shoot them now which combines them short of cracking it out and shooting raw.

kaz · March 15, 2012 10:39AM

I've used a milky plastic juice jug with the bottom cut out; set if over the coin with the lens looking down the top (also cut out) and light sources on 2 sides of the jug. this eliminates the slab glare, the devices are lighter than the fields.
axial light will only work on a raw coin.

OriginalDan · March 15, 2012 2:26PM

Thanks for the tips guys. Kaz I think your method works great for most situations, but the side lighting doesn't bring out the color I'm trying to show. Looks like I'll have to work this one out on my own.

blu62vette · March 15, 2012 2:36PM

I never diffuse the light.

stealer · March 15, 2012 3:06PM

From a novice photographer as well, diffused lighting lets you capture the color but the color will be muted and there will be no luster.
The coin will look butt ugly in other words.

OriginalDan · March 15, 2012 3:31PM

Maybe my light source is too narrow, but without diffusing the light, I see all kinds of pin-scratch type hits on the coins, with little chroma colored speckles. How do you guys avoid that without diffusing the light?

Edit: And maybe I'm misinterpreting your response, but was your comment on not diffusing the light in reply to the original post? Mind explaining how not diffusing the light will improve this particular scenario? It's a process for me, that I'm working through, but any tips you can offer are greatly appreciated.

nwcoast · March 15, 2012 3:33PM

I've found that diffuse lighting works in capturing the colors of deeply toned coins yet as others mentioned, it eliminates the visualization of luster. Being that the coin is behind plastic, axial lighting will only give you the glowing reflections as seen in the photos you've attached.
As a general rule lights positioned at 45 degrees to the side (classic copy lighting) will eliminate the reflections.

Contrast adjustments aren't going to help you here. Ou must work with the light positions relative to the reflective surface of the slab. Move them off to the side so the reflection bounces away from what the lens is seeing. The angle of reflectance is equal to the angle of incidence. In other words, if your light were to be truely axial and coming down from the lens, then it would be reflecting straight back into the lens. Unless some of the angles are adjusted, axial lighting is going to be very challenging with that slab.

It looks like you're on the correct path though and you said it yourself in that you're going to have to experiment some more with the adjustments.

You can use diffuse light without it being axial. Try moving the lights off to the ide and placing some diffusing medium between the lights and the coin.

Just speaking from my experience here. Though i have a great deal of photographic experience, my coin photography expertise is much less than many on here and I'm still learning all the time. That's one of the things that makes this such a great place- all the sharing.

OriginalDan · March 15, 2012 3:40PM

Thanks nwcoast, that's helpful.

I do understand the theory of using the angles to avoid the slab glare. My struggle has been to reflect the light off of the coin in an attractive way, without also reflecting the light off of the slab. Time for more experimentation and practice.

OriginalDan · March 15, 2012 4:25PM

Cool! I prefer #2.

MikeInFL · March 15, 2012 11:42PM

Try adding a second light and moving the reflection points off the coin itself and to an area just outside the coin. That way the mirrors will "light up" but not cause the loss of contrast from reflection off the slab as shown in your first photo. Good luck...Mike

OriginalDan · March 15, 2012 11:56PM

<< THX Dan, so what grade yah give her? >>

Definitely not a series I'm familiar with, but I'll take a SWAG and say 64 or 58 if there's rub.

OriginalDan · March 15, 2012 11:59PM

<< Try adding a second light and moving the reflection points off the coin itself and to an area just outside the coin. That way the mirrors will "light up" but not cause the loss of contrast from reflection off the slab as shown in your first photo. Good luck...Mike >>

This method has worked great for me on normal, not proof coins or coins without as much color. But I can't get the color to pop with this method, I think it's because my lights are not close enough to the lens. In order to fix this, I'm going to try to move the lens further from the coin which will bring the lights closer and make the angle of incidence that much smaller. Will experiment this weekend.

messydesk · March 16, 2012 12:04AM

My initial approach to this would be to diffuse the light a lot, since you want color instead of luster. The picture may have slightly lowered contrast, but you can correct that in post processing fairly easily if the lowered contrast is uniform across the image. The first thing you'll need to do, however, is polish the slab. Those scratches will really pop if you boost the contrast in post-processing.

Whether you need to move the camera higher depends on whether you need more room to get the lights where you want them. A 90mm-equivalent lens (I assume this means a 60mm lens on an APS-C camera) gives less working distance than I'd like.

I've never had any luck mixing axial lighting and slabs and getting better pictures than I can get with non-axial lighting.

OriginalDan · March 16, 2012 12:15AM

Thanks messydesk, you and others are setting me on the right path. I have a number of things to experiment with, hopefully I'll have time this weekend and will report back.

Close btw, I'm using a the 45mm Panny/Leica on a MFT body. Fantastic little setup. I have access to a Canon APS-C body with 100mm macro which should allow a lot more room to play with the lights.

Edit: yes the slabs will be polished! I figure there's no point until I get the lighting right though!

coinkid855 · March 16, 2012 12:36AM

Axial lighting. It's a pain in the you-know-what though. Here's the same coin straight on and again ligthed axially.

-Paul

phnatacc · March 16, 2012 12:55AM

<< Axial lighting. It's a pain in the you-know-what though. Here's the same coin straight on and again ligthed axially. >>

Did you use a polarizer filter on your lens to cut the haze/glare that is produced when using axial lighting while shooting through a slab?

blu62vette · March 16, 2012 12:56AM

I have not used one.

messydesk · March 16, 2012 1:03AM

Polarizer won't do you any good. Worst case is that it will introduce rainbows in the slab itself.

mgoodm3 · March 16, 2012 1:16AM

Since you are already using diffusion on the LED, try varying the distance of the diffusion from the light. moving the diffusion closer to the coin should help make the light spot larger. LEDs are normally a point source and that will make it harder all around than a larger light such as a typical lightbulb.

OriginalDan · March 16, 2012 2:02AM

<< Since you are already using diffusion on the LED, try varying the distance of the diffusion from the light. moving the diffusion closer to the coin should help make the light spot larger. LEDs are normally a point source and that will make it harder all around than a larger light such as a typical lightbulb. >>

Thanks Mark, I kind of figured I was limiting myself with the LED. I'll also try the trick with the diffusion distance to light source.

OriginalDan · March 16, 2012 2:02AM

<< Axial lighting. It's a pain in the you-know-what though. Here's the same coin straight on and again ligthed axially. >>

Very impressive Paul, I was not as successful as you. Nice coin and I'm glad you were able to bring out that great color.

1Bustcollector · March 16, 2012 2:07AM

Beautiful Trade Dollar!

Although my photo experience is limited to raw coins, I am finding the same issues as you have. What I notice is that the size of the coin matters a bit with the type of light source in conjunction to distance makes shooting so dynamic. Your coin is large, it appears the light is more intense at the center and does not cover the entire coin in an evenly lumen distribution. Flood lights distribute a larger area of light and spot lights are more concentrated. I just switched to an L.E.D. style bulb with 680 lumens but have found other lights at the same output have different outside diameters of measure. I went to my local light store and tried out some lights, but now I am thinking about taking my light set-up over there and try them out in "my" copy stand. I like the idea of pulling back the light a bit to evenly cover the coin (if possible without losing color) possibly using a diffuser from a tupperware lid and then adjust "render" in Photoshop but it takes sooooo much time-probably because I do not know what I am doing. The lid needs to be moved further away from the bulb to obtain a even distribution but you have to play around with this. Again, I am a novice at this myself so if you find better answers please share.

rmpsrpms · March 16, 2012 2:30AM

I've never been happy with any form of axial lighting due to the compromises you have to make with contrast due to the direct reflections off coin or slab surface. Best luck I've had with the Jansjos in showing color similar to axial lighting but without the surface glare or chroma problems is by "shaping" the diffuser to eliminate the direct reflections. This also simultaneously gives good proof contrast, though I don't own a beautifully-toned proof to show an example. Look down in this post to see the pattern that gives me a good result on both raw and slabbed coins. The diffuser is actually quite easy to make. PM me if you want instructions...Ray

rmpsrpms · March 16, 2012 2:32AM

<< 

<< Axial lighting. It's a pain in the you-know-what though. Here's the same coin straight on and again ligthed axially. >>

Did you use a polarizer filter on your lens to cut the haze/glare that is produced when using axial lighting while shooting through a slab? >>

Polarizers won't help. The glare is directly-reflecting off the slab surface. Polarizers only work when the reflection is at an oblique angle...Ray

coinkid855 · March 16, 2012 2:55AM

<< 

<< Axial lighting. It's a pain in the you-know-what though. Here's the same coin straight on and again ligthed axially. >>

Very impressive Paul, I was not as successful as you. Nice coin and I'm glad you were able to bring out that great color. >>

Thanks! Keep trying, it takes a bit to get the hang of it!

-Paul

OriginalDan · March 16, 2012 9:09AM

Getting there:

I moved the light source higher and closer to the lens, and moved the diffusion away from the light, closer to the coin. I'm still not happy, it's a bit flat and the luster is totally washed. At least I've mostly eliminated the slab glare. The process continues...

Next step is to bring out the halogen's and copy stand setup. I'll have more adjustability and the lights should be much easier to deal with.

Photographing proof coins with color

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