Daniel Reetz, the founder of the DIY Book Scanner community, has recently started making videos of prototyping and shop tips. If you are tinkering with a book scanner (or any other project) in your home shop, these tips will come in handy. https://www.youtube.com/channel/UCn0gq8 ... g_8K1nfInQ

What I learned about Lighting from setting up a copystand

All about lighting. LED, CFL, Halogen, Other? Questions and info about lighting go here.
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daniel_reetz
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What I learned about Lighting from setting up a copystand

Post by daniel_reetz » 03 Jan 2010, 17:52

So, my Christmas gift to my Mom was to digitize all the family photos. We have about 3,000 family photos in various albums and shoeboxes.

The camera that was to do the digitizing is an old Canon Powershot A95. It was my Mom's old camera, but she was getting a Powershot SD1200 IS for xmas, so I knew it would be available.

Specs on the A95:
5.0 M pixel, 1/1.8 inch type ccd
Lens Focal Length 38-114mm, f/2.8 (W) - 4.9(T)
Focusing Range Normal AF: 18 in./45cm - Infinity
Macro AF: 2 - 18 in./5 - 45cm (WIDE), 9.8 - 18 in./25 - 45cm (TELE)
Autofocus System 9-point AiAF/1-point AF (FlexiZone, fixed to center)

Image

I brought my old copystand, the same one I used to make the first book scanner. It's a versatile piece of gear. It has four lights mounted on arms. I'm using just 4 standard 60-watt bulbs in there. No halogen or other exotic stuff. As it turns out, I have almost no good pictures of this device as a copystand, just as the first scanner. I found two pictures of it in the back of other pictures:

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Image quality and speed of capture were my highest priorities. For this reason, I decided to do a few test captures. First, I had to set the White Balance to Tungsten, from Auto. That produced remarkably accurate colors. I also noticed that if I didn't set the WB to Tungsten, the camera, for whatever reason, decided that clipping in the red channel was a good decision. I don't know about you, but I'm used to making WB decisions in post from RAW images. However, since this camera doesn't do Raw images, that would have been lost information. From here on out, I'm going to be sure to set correct WB even when shooting RAW.

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With this kind of project you want the pictures to be flat. If they are not flat, there would be problems with specular highlights, distortion, etc. Luckily for me, the pictures were mostly flat, with a few exceptions. Glass would be able to flatten the pictures, if they weren't flat. Did I need it??

So yeah. The first major decision to make was whether or not to cover the picture with glass.
  • 1. The first thing about glass is that it has a time-cost. Moving and replacing the glass takes time. If the glass is smudged or dusty, it must be cleaned.
    2. The second thing about glass is that it causes increased glare and reflections.
    3. The third thing about glass is that I did not have an ideally-sized piece, just A4-sized scrap from a broken scanner.
So I shot some test shots with glass. With the "stock" setup, the images were pretty rough. The "with glass" image in particular had a plainly visible image of the camera present, and dust/glare problems throughout. It was clear that I did not want to use glass if I didn't have to.

The strange thing is that even without the glass, in the glossy-surfaced photographs there were issues with the camera showing up.

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Here's a close-up of a without-glass image that clearly shows the camera reflection:

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I wasn't about to digitize three thousand photos with a big camera image superimposed on them. :shock:

So I thought about the problem for a bit. The primary issue is that light was reflecting off of the camera, onto the picture surface, and back into the lens. In principle, if I could reduce the amount of light hitting the camera, I could reduce its reflection. If I could make the camera completely dark, I could eliminate its reflection entirely.

The first idea I had was just to make some crude "louvers" or "barn-doors" like they have on theater lighting. I grabbed a cardboard box, a stapler, duct tape, and slapped these louvers on the machine:

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I found that this did reduce the reflections substantially, but not completely. I tried averaging together a few dozen images from the copystand and the camera reflection popped back out at me. And as in the image above, my arm was visible because I had to touch the camera to press the shutter button.

After a bit more thinking I decided to make a shroud for the camera in addition to the louvers. This worked absolutely marvelously. I cut a little slot for the little screen to hang out in case I needed it. The shroud had to hang pretty far down on the camera to completely eliminate the camera's reflection, but it worked so well that I didn't mind the ugliness and clumsiness of this duct-taped piece of cloth.

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The results were really nice: (the actual images are much higher resolution)

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There are a few lessons in here, I think.

One is that we could reduce camera reflections in our book scanners with light shields that blocked light coming from above.
Two is that we can additionally block light coming from below.
Three is that averaging a load of images can show the extent of a reflection.
Four is that tungsten is a good alternative to halogen in some circumstances.

EDIT: Big thanks to my brother POODUS for helping out with these images and this project, would have been impossible without him.

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Re: What I learned about Lighting from setting up a copystand

Post by daniel_reetz » 03 Jan 2010, 18:01

The other thing I did was to make a power supply for this camera, so that it would never move from the copy stand.

The camera itself has some weird size power connector. I found one on the Mintek DVD player that is sitting on the copy stand in this image:

Image

The power supply itself was totally rigged. It consisted of a 5V wall-wart power supply from a broken Zip drive (is there such a thing as a non-broken Zip drive?? click click click). The power supply kicked out something like 5.5V when not under load. The camera was spec'd for 4.3V input, so I thought that perhaps doing something really crude and putting a big diode across the positive lead would drop the voltage far enough. I had a little trouble finding a tough enough diode, but then I remembered that bridge rectifiers are just 4 huge diodes that are designed to handle some current. So I found a bridge rectifier in an old 10baseT hub, desoldered it, and wired 1/4 of it in line.

When the camera was connected to the DVD player, it worked flawlessly. When it had to power its internal screen, it complained of low battery. However, it shot over 2400 images without a single problem using this supply. After a lot of pictures in quick succession, the diode would get hot, but not dangerously so. I think it's a totally workable setup and if I need to to mass digitization like this again, I'll set this exact same thing up.

Ann

Re: What I learned about Lighting from setting up a copystand

Post by Ann » 03 Jan 2010, 18:35

We haven't had problems with the camera itself reflection on anything, I think because of our black "tent" that we drape over the system. But, I do get glare/reflections from the lights themselves if they aren't in just the right spot all the time. I'll try making some simple louvers like you did and probably put them underneath the lights to diffuse the light upwards - maybe - if this doesn't put too much light onto the camera itself; since I'm using compact "sunlight" fluorescent bulbs there is no heat problem and I when I set the LiveView function in the EOS Utility to "sunlight" it produces a pretty correct white. Thanks for the louver idea!

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Re: What I learned about Lighting from setting up a copystand

Post by rob » 03 Jan 2010, 18:41

So did you do all this hokeying up away, or at your workshop first? Because if the former, I think this would cement your reputation as a mad scientist to your folks!
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Re: What I learned about Lighting from setting up a copystand

Post by daniel_reetz » 03 Jan 2010, 19:03

I did it all there in my brother's bedroom, using just the junk I could find, though I sorely wished I'd planned ahead, especially with the power supply. Took me quite a while to think of that simple solution!

Still haven't put my Mom's DVD player power supply back together... :oops: At least she's pleased with the scans!

Ann, thanks for all the documenting you've been doing -- please let me know if the louvers solve anything for you! One of the things I'm eventually going to do with my portable scanner is to take the pictures right-and-left sequentially, switching on only one side of my LED lighting at a time... that should totally eliminate the reflection "crosstalk" I have (which is admittedly minor).

Ann

Re: What I learned about Lighting from setting up a copystand

Post by Ann » 03 Jan 2010, 19:26

Hey Dan - I'll be getting back to compiling two mini-books - samples we need to include in a grant proposal - to show that we can carry through with our NARA project; they won't be complete eBooks, but at least several pages of 700 page books of the date and probable physical size we will be scanning. I need to re-shoot some pages that turned out OK, but not as good as we want. The louvers might help, and we've changed the light bulbs. We increased the wattage from 40 to 100 and also to "sunlight". Really helped. And stabilizing our crossbar made a world of difference; we're also going to take the hinges off our cradle and just see if they'll sit there loose, crossed over one another, and be stable enough. If not, some dark strong tape on the back should take care of that. The hinges are getting in the way and don't allow the two mud flaps to touch each other, which can be a problem with thin or singular items, like the Archaeology mag I did a few pages of.

Ann

Re: What I learned about Lighting from setting up a copystand

Post by Ann » 03 Jan 2010, 19:30

Oh - and I forgot - some glare is eliminated with our system when we only put one side of the platen plexi in - since I'll be doing only one side at a time, leaving one side empty also helps to position the book/magazine being scanned if it needs some adjustment. And, in the case of flat scanning with the flat cradle - 2 pages at a time with loose-spined books - the platen can be left off completely or ignored, with just one sheet of plexi on top of the book to flatten it.

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Re: What I learned about Lighting from setting up a copystand

Post by StevePoling » 04 Jan 2010, 01:22

Older prints, particularly color prints are prone to fade. I've got three shoeboxes of my parents' (and grandparents') photos. Because those shoeboxes had a bunch of negatives, I purchased an Epson v500 photo scanner (http://www.amazon.com/Epson-Perfection- ... B000VG4AY0). I've scanned only one shoebox so far. (You can see them around here:http://www.facebook.com/album.php?aid=1 ... =614244796) I've scored major points with my cousins who are on Facebook. And I loaded a couple digital photo frames for my Step-Mom and my Aunt Lillie with these pics. Scored double Christmas points. (My cousins will be grateful when I quit fussing with book scanning and get back to family photos.)

The best results come from scanning negatives or slides. (But you really need to be careful about fingerprints, dust and lint.) Color adjustment helps restore an image, but I've gotten better results from negatives. Consider the relative quality of these two images:
http://www.facebook.com/photo.php?pid=2 ... =614244796(from print)
http://www.facebook.com/photo.php?pid=2 ... =614244796(from negative/slide)

That said, I have one photo of my great-grandma that is impossible to scan. Glare is going to be a major issue since I can't easily remove the photo from its frame with its convex-curved glass. When I get my bookscanner working, I'm going to try to copy it therewith.

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Re: What I learned about Lighting from setting up a copystand

Post by daniel_reetz » 04 Jan 2010, 07:27

One thing I've done (and this is another HUGE project that I'll be sharing at some point) was digitized some old paintings that are on the wall of a business in downtown Fargo. They've been varnished over, so from EVERY angle you get these awful specular highlights and glare on them. What I realized is that if I took pictures of these paintings from multiple positions (effectively moving the specular highlight around), aligned them, and then picked the median value at each pixel, I would totally eliminate the specular highlights. Indeed, that is exactly what happened. You might be able to get away with just pointing the camera at the frame, shifting it left-right, up-down, and masking out the "good parts" in Photoshop. The other gain you get is a lot of "extra" pixels due to camera shift.

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Re: What I learned about Lighting from setting up a copystand

Post by Misty » 04 Jan 2010, 11:14

Dan, I noticed that the EXIF info from your files seems to have been stripped. It'd be worth keeping that in the web size copies - that way, people can take a look at your exact shooting settings.
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