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Numismatic Photography Thread, Flat vs angled in Miscellaneous Numismatic Information; I imaged a buffalo nickel with the coin flat using 2 lights at 11 and 1, and then imaged the ...
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    Member rmpsrpms's Avatar
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    Flat vs angled

    I imaged a buffalo nickel with the coin flat using 2 lights at 11 and 1, and then imaged the same coin with the coin slightly tilted and with a single light reflecting directly off the coin to simulate axial lighting. This "pseudo-axial" lighting makes the coin look more like it does "in-hand" than any other method I've found. Anyway, here are the pics:

    Lights at 75-deg



    Lights at 90-deg


  2. #2
    Toning Freak! Lehigh96's Avatar
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    The overall difference in color is dramatic. While I like the color profile of the 75-deg photos, I think the 90-deg photos show better detail.

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    Administrator Jesh's Avatar
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    I like the 90' more. A little editing of these and a solid background and it's pop even more. It's a good 'psedu-axial' shot

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    Member rmpsrpms's Avatar
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    A problem with axial-type lighting is its inability to show luster. The technique shows surface color well, in fact better than any other, but luster is created by local contrast between areas of direct and oblique specular reflections. When you use axial-type lighting, you maximize direct specular reflection from all flat surfaces, so in effect the coin is "lustrous" all over. Another problem is that since so much of the light reflects directly off the surfaces, the color shifts toward that of the light source. I have yet to figure out an effective method to white balance an axial photo. I'm thinking of simply using a mirror and see how it comes out. Come to think of it, this might also be the best method for setting up the correct reflection angle, and for ensuring lighting uniformity. I think I just hit on something! ...Ray

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    Administrator Jesh's Avatar
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    Try it, I'd love to the see the results. The only problem I see with the 2nd images (at 90') is it seems over saturated now that I'm on a calibrated monitor. However, you know how coins are that are toned. The one as my avatar is a heritage shot, the 'real' in hand pictures look so crazily colored I'd probably say they were over saturated too if I didn't see the coin in hand.

    Anyhow, I like them. Let's see any different ideas you have on taking shots of it!

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    Member rmpsrpms's Avatar
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    I ended up using a Lincoln Cent to test the new technique and took photos with more standard techniques to compare. I wanted to publish the results also on LCR forum which is why I chose the Cent as subject.

    You will see in the photo the new arrangement, which I can use for flat or angled imaging. I put a small mirror on the microscope stand base, and then put the reversible stage plate on top of the mirror. The mirror is useful for calibrating flatness when doing flat imaging. For angled imaging I hinged the mirror by taping it down to the stand on one edge.

    Let's start with a sort of reference photo, single light, un-diffused, at 12:00, 90mm above the coin, 80-deg from horizontal:


    As a second reference, here is my "normal-direct" lighting arrangement with 2 lights, un-diffused, at 10:30 and 1:30, about 90mm from the coin, and 75-deg from horizontal. The resulting coin photo is shown below the setup:



    As final reference, here is my "normal-diffused" setup using the "Directors" I built for minimizing hotspots, again with coin photo below:



    Here is the first experiment..."direct pseudo-axial". This is somewhat comparable to the 90-deg Buffalo Nickel photo shown earlier except that was with a small amount of diffusion. The setup uses a single light, un-diffused, shining directly off the coin to the camera. First pic is of the setup. Second pic is of the lighting calibration showing the reflection of the light off the mirror in center of image. Third pic is of the coin:




    And finally here is the setup similar to above, but with a new Director that directs the light more evenly across the image. First pic is of the setup, second of the calibration, third of the Director used, and fourth pic is of the coin:





    Since axial lighting results in fairly extreme shadowing, my next experiment will be to add some auxiliary lighting to the pseudo-axial setups. I'll try it with both direct and diffused axial as primary and see how it goes...Ray

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    Member rmpsrpms's Avatar
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    OK, I tried my original "line source" Directors with tilted pseudo-axial technique, and here is the result:



    I'm very happy with it. Still no luster shows, and it may be that a better way to light the dark areas of the coin is by using an un-diffused light than will pick up some luster. I will try that as well, but just thought I'd publish this for comment.

    By the way, also took a pic of the Buffalo Nickel using the same technique for comparison...Ray


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    Administrator Jesh's Avatar
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    Still some excellent images. If you ever get around to writing a full article I'd like to post it on our main article page

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    Toning Freak! Lehigh96's Avatar
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    That is a fantastic method you have developed there, but I have to ask one question. What is the purpose of using the tilted pseudo axial technique on a coin that can be properly photographed using direct overhead lighting? What I am saying is that diffused lighting is usually used to show color that can't be captured with direct lighting. If there is no discernable improvement in the color, the only effect of using the technique would be to lose the luster.

    That said, there are coins that exhibit iridescent toning that is practically impossible to capture using direct lighting. For these coins, the direct lighting shot would be necessary to show the luster and hint at the underlying color while the tilted pseudo axial technique would be used in a complimentary fashion to correctly show the color. I have a perfect candidate for your experiment.




    The first photo is mine and shows the excellent luster of the coin using direct overhead lighting but does not adequately capture the color. The second photo is the Heritage photo which loses luster and shows the color. I don't know what their photographic setup is, but I have to believe that the lighting is diffused in some way.

    If you want, I will send this coin to you so that we can further explore your experiment. If you are interested, please PM me with your address. Let me know!

    Paul

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    Member rmpsrpms's Avatar
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    Quote Originally Posted by Lehigh96 View Post
    ...What is the purpose of using the tilted pseudo axial technique on a coin that can be properly photographed using direct overhead lighting? What I am saying is that diffused lighting is usually used to show color that can't be captured with direct lighting. If there is no discernable improvement in the color, the only effect of using the technique would be to lose the luster.
    Agreed, if the coin shows best with standard lighting there is no need for this technique. But most of the coins in my "permanent" collection are toners, some of which have been hard to photograph with full color. You can see the strong differences in "look" between the techniques applied to the Lincoln Cent I showed above, so this seems a candidate. I was interested in trying this out as a response to coins that have deep underlying color that only shows with axial lighting. Also, a few coin photographers use axial almost exclusively and swear by it, so I wanted to figure out an easier way to do it.

    If you want, I will send this coin to you so that we can further explore your experiment. If you are interested, please PM me with your address. Let me know!

    Paul
    Will do, should be interesting. All axial techniques work best with raw coins, since the light also reflects directly off the slab surface. But there are perhaps methods to improve on this as well...Ray

 

 
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