Photographing a slabbed coin
Cascadecoins
Posts: 44 ✭✭✭
Any tips on getting high quality photos without glare through the plastic of a pcgs or ngc coin slab?
The quality Great Collections can produce is pretty incredible and they have identified a superb workflow for capturing certified coins.
The darker blue background they put behind seems to make the coins “pop” even more.
Does anyone know what technique Great Collections is using?
Here’s a 38 d/s as an example of my capture through the plastic slab. 
Thank you.
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What a coincidence, I just posted this in another thread, just a few minutes ago
I’m a lazy photographer and don’t have the patience for real professional photography, but I find that if I put a few drops of optically clear compass oil on the slab right on top of where the coin is, that it makes a dome of oil that causes lighting reflections and slab glare move off of being right on top of the coin and only visible on the periphery of the dome of oil. It’s like the slab on top of the coin becomes invisible to the camera. Like this:
It works on NGC slabs too, which tend to have more glare/reflections than PCGS
Mr_Spud
This is the compass oil I’m using, it’s basically volatile mineral oil that slowly evaporates, so I can wipe it off with a paper towel and any residue I miss will evaporate off
Mr_Spud
You might try tilt them up on a small book under a 100 watt lamp.
Based on my attempts here https://forums.collectors.com/discussion/1103994/inspired-by-deplorabledans-post-this-is-my-second-try-on-photography If the slab's not scratched, you shouldn't need the compass oil. You just need really bright directed lighting (on the order of 75-100W incandescent equivalent) at an angle where the light is not quite reflected into the lens.
Not a fan of the oil method - tried it ~20 years ago - it's a mess and not necessary.
Coin Rarities Online
Go with, “Daylight” fluorescent bulbs in highest wattage you can find. This will give you excellent light coverage and makes a huge difference. Then I use a ikon SLR box with a macro lens. All together with s copystand will help immensely. I enjoy working with my setup.
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Can you repeat with the same lighting and no oil? The only thing I use oil for is to hide scratches, I just smear it on, making sure I don't leave bubbles or dust in it, then wipe it off. I would think that a "dome" of oil would cause reflections of the lights into the camera at a lower lighting angle than without, sort of like the problem with photographing bulged NGC holders. On the other hand, the surface of the oil is optically better than that or a slab, especially some of the older NGC slabs, so it would help with that.
What will help you light a slab at a higher angle is a longer focal length lens. The narrower field of view with these applies to the reflected lights as well as the subject, allowing you to be able to move the lights closer in.
Another thing I haven't tried is a plano-concave lens optically coupled with the slab with oil such that as far as the lights are concerned the surface of the slab is slightly concave, allowing you to get the lights much closer before getting a glare. The lens would be close enough to the coin that it shouldn't result in any distortion. To CRO's point, however, still a mess, but perhaps worth it in some rare cases.
Keeper of the VAM Catalog • Professional Coin Imaging • Prime Number Set • World Coins in Early America • British Trade Dollars • Variety Attribution
@messydesk That particular coin is at the bank Safety Deposit Box, so it would be hard to get it for the experiment. I used my cell phone for that picture and no professional setup. Let me look for a thread I made a while back where I was experimenting when I first started using the oil where I may have some with and without oil images of a toned dime in an NGC slab and if I find it, I’ll copy and paste some of it here. I know that with a legit camera, copy stand and good lighting that you can get the camera to focus on just the coin itself and eliminate most glare and reflections from the slab, but I’m not set up for that. I’m just using this setup and find a huge difference when I use the compass oil and it’s a quick and easy hack, but not too professional and not the only way to do it. In the pictures, I’m using a 250cc plastic pill bottle as a copy stand. That’s what I took the picture of the large cent with, only I was still using an Ott light with inverted V shape, shown in the 3rd picture below, I switched to the gooseneck led ones in the first 2 pictures below shortly after I took the large cent pictures. The oil drop dome only shows light reflections and glare on its periphery and not over top of the coin. Even the light reflection bends around the coin and isn’t on top of the coin anymore. Without 5he oil, those light reflections would be showing right on the edges of the coin itself.
Mr_Spud
I couldn’t find the thread doing a quick search, but here’s one of the pictures I found on my camera roll that was in the thread. In the picture below, the image on the right was the best I could do with my cell phone without the oil trick and the image on the left was after using the oil trick. I did other things for both images, such as using manual focus and using a jack lift (2nd picture below) instead of my plastic bottle to fine tune the focus like it was a stage microscope, and was using a layering trick for the one on the right to get the colors to show, so other factors involved, but both represent the best I could do with and without the oil trick. For the large cent in a PCGS holder, I didn’t need the jack lift or manual focus, the coin is big enough and no white insert like NGC that autofocus worked. Without the oil trick, the autofocus focuses on the slab and the pictures come out not as well focuses, but the oil trick makes the slab invisible to the camera. But for small coins in NGC, the white insert and slab glare are what the camera tries to focus on.
And, here’s the image of the large cent again pointing out how the straight row of the inverted V shaped Ott light reflections bend into a curved shaped reflection around the periphery of the oil drop dome along with the translucent slab glare so they aren’t on top of the coin like they would be without the oil trick
Mr_Spud
John, you might change your mind after you try the compass oil. It has to be that specific oil that we posted the amazon link to. When I've done it with mineral oil, it was a messy pain in the ass. The compass oil has properties that make it much easier to work with, only use for slabs that have scratches otherwise it's unnecessary.
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I don’t remember where, but I remember reading where they used to use whale oil in compasses, because it’s optically clear, so that’s part of the reason I ended up trying the compass oil. It has something to do with this kind of stuff they do with oil immersion microscope technology and bending of light rays.
But the other reason is because the particular Compass Oil that’s on Amazon is Isoparrafin, a type of volatile mineral oil I was familiar with because it was one of the odorless volatile oils that was screened during the development of this invention of a twist off Softgel capsule for use as a perfume sampler https://data.epo.org/publication-server/rest/v1.0/publication-dates/19980114/patents/EP0671901NWB1/document.pdf . I actually did the work on developing the odorless gelatin, but the cosmetic group developed a fill material that you dissolve concentrated perfume base into instead of the usual alcohol because alcohol isn’t compatible with gelatin. Isoparrafins worked as good as the volatile silicones they ended up going with for the patent. Isoparrafins are available at different viscosities and evaporation rate, are odorless and don’t leave residues. So when I found the compass oil on Amazon, and it said they are using isopar, I knew it would be worth trying. I was really just looking for something to hide slab scratches that wouldn’t leave a residue like mineral oil and it wasn’t until I tried it that I saw it bent the light reflections and slab glare like that, but after that I always used it because it made it much easier to get the coin to light up properly with the lighting being much easier to adjust. With my cell phone pictures, I often ended up with lighting reflections and/or glare right on the edges of the coin if I wanted to light up the whole coin and make the colors come out good
Mr_Spud
Here’s info on the Compass oil manufacturers website saying it is isopar L:
And here’s a link to the safety data sheet from the raw material manufacturer, Exxon https://www.gcascc.com/wp-content/uploads/2018/09/ISOPAR_L_EN.pdf it’s more formally a heavy grade of Naptha that evaporates slower than regular Naptha so sort of in between liquid paraffin ( mineral oil) and regular Naphtha (basically refined lighter fluid)
Pardon my wordiness, I just finished an Energy Drink and I’m bouncing off the walls. I’m gonna go clean the house now, trying to overcome a mild ant infestation.
Mr_Spud
Taking break from cleaning, I searched for isoparrafin and found the compass oil. If you replace silicone oils in cosmetics, you can make them clearer looking. Like this kind of stuff https://patents.google.com/patent/WO2000015191A1/en . Most likely the different grades of Isopar would bend light differently. I wonder if Richie compass oil company did testing to see which provided the best optical properties or not 🤔
Most likely they picked one that worked best in their compasses. But maybe one of the other Isopars is probably better for forming a droplet dome. When I make the oil drop “dome”, besides allowing the lights to be closer together over the coin without making reflections, it also seems to help light the coin more evenly similar to how Magnabrite giant magnifying lenses light up what you look at through them. Maybe one of the other grades would work even better
Mr_Spud
The oil I use is Ultra Pure Lamp Oil. It comes in a 18 oz. bottle, so I put a little in a dropper bottle and have it on my desk and can take it with me. I also use it to oil the valves on my horn.
Keeper of the VAM Catalog • Professional Coin Imaging • Prime Number Set • World Coins in Early America • British Trade Dollars • Variety Attribution
Ultra Pure Lamp Oil may be purified mineral oil with little volatility or it might be Isopar L.
Mr_Spud
I have a new camera and am getting a copy stand later this week. With some new lighting, this was the first 10 minutes of playing around. Not too shabby. Ive never been able to photograph proof coins well. I have some work to do with the slab glare on the top right quadrant, but so far, I am pleased.