What Kind of Glass and Lighting for Print Copys

<p>I'm looking to duplicate several watercolor prints. I'm going to use a copy stand, but I also want to use a sheet of glass to keep the prints as flat as possible. I'll probably use the same setup for copying prints later. The two questions that I have:</p>

<p>1. What's the best type of glass to get at the local glass shop. I can get a 1/4" clear sheet of standard coffee table glass or I can get a sheet of low reflective glass for a picture frame. I'm thinking the low reflective will be better to reduce any unintended ambient light. But clear glass should also work as I can simply control the angle of incidence to my lighting to make the reflections disappear. The clear glass I can also use for any product shooting that I want to do.</p>

<p>2. Whats the best light source? Should I use some cheap continuous lighting so I can reduce shutter speed to my liking. Or should I use a couple of mono-lights. I'm leaning toward continuous because I can make it myself on the cheap. Just purchase a few good bulbs and correct for white balance. Should I be trying to use any kind of light modifier like a softbox or just hard directional lighting?</p>

<p>I tried a test a while back making print copies off a tripod and I liked the results of my scanner better, but the speed and advantage of large print size is very appealing.<br>

Thanks for the help.</p>

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<p><em><strong>I want to use a sheet of glass to keep the prints as flat as possible</strong></em>. </p>

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<p>Better idea; have someone make a vacuum table for you. You need peg board, a box(well sealed except for the pegboard top), a vacuum cleaner and some heavy tape to coverthe holes outside of the paper area.<br>

Lighting: hard directional, with polarizing gels over them. Make sure the light is evenly distributed from center t ocorners within +/- 0.10 stops. Also use a polarizing filer over your lens. </p>

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<p>Dont know if using glass is the best idea here. It might bounce back reflections from things behind the camera and these will affect your image.</p>

<p>If it were me, I would hang the painting on a wall somehow, so its pefectly straight both along the vertical and the horizontal (use a level). Then position your camera and lens on a good tripod dead center with the center of the painting. (Also level the tripod).</p>

<p>Use 2 identical continuous running lights. Put one to the left, and the other to the right. They shoulc be equal distance from the painting and from the camera. If you drew an imaginary line from the light source to the painting center, the angle between the lights and the camera should be 45 degrees. And the angle between the lights and the wall should be 45 degrees. This setup will provide equal lighting from both sides, and each light will fill in the shadows from the other light.</p>

<p>Of course, as you experiment and tweak the setup, you can increase the brightness level by moving both lights closer to the drawing. Or you can reduce the brightness level by moving the lights away from the drawing. In this way you can adjust the brightness level till you find just the right spot.</p>

<p>For maximum sharpness, I would suggest you shoot in aperture preferred mode, set a medium aperture like f8, and let the camera pick the shutter. Also use the camera's builtin self-time delay so you can take hands off the camera after setting the AF point and pressing the shutter. Doing this will result in a stationary camera and subject, which should result in very good sharpness.</p>

<p>In order to get the very best color hues, you may want to consider using an Expo-Disk, as you are essentially taking a portait of a painting. The Expodisk will enable you to set a custom white balance setting on your D-SLR, one that is matched to your particular lights and how you have them positioned. That custom white balance setting should be good as long as you dont change the lighting.</p>

<p>happy shooting...</p>

<p>If there is some border space, you may be able to simply weight the edges with metal rules, bar stock, etc. Agree with Ellis that a vacuum back is great if the effort makes sense to you (watch out for vibration from vacuum cleaner or other vacuum pump). If you need to use glass, suggest avoiding the non/low reflective (I think you will lose some sharpness otherwise). I would also suggest using thinner than 1/4". I think you will find it much easier/practical to use the copy stand. Whether you shoot vertical or horizontal, kill any other light source in the room and avoid any light from the copy lights falling on the camera. If you still end up with a reflection, you may be able to eliminate by using a large flat black card (or cloth) to (with a hole for the lens). Based on your comment re white balance, assume you are not using a view camera. If you still end up with a reflection of the camera/lens, and need to use the glass, you can definitely avoid a reflection by shifting the camera laterally (keeping the sensor parallel to the watercolor) so that the camera does not "see" its reflection in the glass. Obviously you may need to increase the distance from the camera to the watercolor (or use a wider lens) and you will only be using "part" of the sensor for the actual image.</p>

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<p>(watch out for vibration from vacuum cleaner or other vacuum pump)</p>

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<p>This problem is solved by using a hose to connect the vacuum to the vacuum table and possibly putting a rubber pad underneath the vacuum. </p>

<p>Thanks as always for the responses. Fantastic help. I did a few experiments over the weekend using what I had on hand. With glass (from a large picture frame) I did notice reflections when using 2 shoot through umbrellas, which seemed to offer better light. Well it offered better light in the sens that with the umbrellas I saw less dust, but more photo grain (I was testing using a photograph), but with direct lighting I saw dust particles light up, but grain was less. This was all using two speed-lights with the camera on a standard tripod. I dd not have any of the water colors on hand, but figured test with what I have first. Without glass produces the best results hands down - assuming the work is flat. I also now agree any low reflective glass will just decrease sharpness. Even with regular glass there was decreased sharpness.</p>

<p>Also shooting vertical is a pain. Hard to make settings and I had to use a fixed length lens to keep the focal length consistent. In an ideal world I could see having a vacuum box mounted to a wall - no glass and shooting far enough away to avoid reflections.</p>