Message:

<p>[QUOTE=&quot;RonSanderson, post: 3949308, member: 77413&quot;]You did ask about proofs, and also showed a Franklin half, and mentioned GIFs.</p><p><br /></p><p>Here is a Franklin proof. I will discuss technique a little bit below.</p><p><br /></p><p>[ATTACH=full]1040623[/ATTACH]</p><p><br /></p><p>Proofs and business strikes pose their own sets of problems. The mirror-like surfaces of proofs can reflect light back at the camera, making them uniformly bright, or away from it, making them dark. Most photographers choose one or the other as a preferred style. Using multiple images can show the transition of the light across the surface, and animating them can show how the mirror surface actually has subtle contours. (Aside: This is one of my older photos and I would like to retake it now that I have more experience.)</p><p><br /></p><p>As [USER=112]@GDJMSP[/USER] says, a small difference in the light position can have a profound difference on the resulting image. This can be used to advantage. As I have shown elsewhere, I use a setup with the camera mounted on a microscope stand, with axial lighting at the 10:00 and 2:00 positions above the coin. I use a third light, much lower, to cast some light horizontally across the coin to reduce shadows.</p><p><br /></p><p>The entire camera setup sits on a small turntable, while the lights are stationary on the desktop. My current technique is to rotate the turntable about 10 degrees between each shot, taking 9 photos. Since the coin and camera rotate as a unit, these are all perfectly aligned with each other. I straighten, crop, and merge into a .GIF file with .15 second between each frame.</p><p><br /></p><p>This can show some things well, but there are tradeoffs. A .GIF file is big and has compromises. To put together 9 frames, a size of 800x1600 pixels is about as big as you can go and still stay under CoinTalk’s file size limit of 10MB. Each frame can only have 256 colors. As a result you may get adjacent pixels resolving to the same color, losing some accuracy in the color fidelity. So, given the size and color limitations these are not the best for detailed surface examination. If I want to show that, I generate a single still image of 1920x1920, which is again CoinTalk’s maximum image.</p><p><br /></p><p>Business strikes are another matter altogether. They don’t have mirrored surfaces (except rarely) but have luster and color. To show that, I move the lights further off-axis and adjust the exposure to compensate for the reduced light intensity.</p><p><br /></p><p>[ATTACH=full]1040638[/ATTACH]</p><p><br /></p><p>Here you can see that the light is not kicked directly back up into the lens, but that the camera captures the light illuminating the surface (a subtle distinction when I put it into words, but you can see the difference quite readily in the images).</p><p><br /></p><p>Again there are tradeoffs. The images, I personally feel, try to bring in that dynamic play of light that still photos have trouble with. Sometimes they really help when trying to see small shapes, such as whether a Standing Liberty Quarter has enough features to merit a Full Head designation. And sometimes you have to fall back to a well-lighted still photo to get the higher resolution and better color fidelity.[/QUOTE]</p><p><br /></p>

Your name or email address:

Do you already have an account?

• No, create an account now.
• Yes, my password is:
• Forgot your password?

Stay logged in