My super-simple book scanner

[Misty]

While it's going to be awhile yet until I can build my "real" scanner, I thought I'd get over my embarrassment and show the rinky-dink MacGuyvered scanner I've been using to date. Maybe it can help people with somewhat modest needs who don't have the skills to build a more elaborate one.

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The cradle is built out of three-panel presentation boards - you know the kind that you used at the science fair as a kid. The long end makes a good, large surface for the book to rest on, while one fold-out panel acts as the support for the book on the table.

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The camera sits on a tripod mounted on the table, pointed at the board's surface; I angle the board so that the camera faces it straight on, providing a straight image with minimal keystoning. However, limits on the tripod's height makes it hard to scan oversize objects perfectly straight on - with this design, I've had to scan some oversized books slightly skewed, and straighten them in software. I've also had to skew when I'm using glass in order to prevent glare. I broke my big piece of glass recently though - luckily I don't have much that needs glass right now.

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I've placed black bristol board for the backing underneath the book, over the presentation boards' white surfaces. I've found that using a white backing results in more light being reflected back into the camera, and that results in poorer contrast in the image and higher amounts of image noise; a black background gives much better looking scans. Here's a couple samples:

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White background

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Black background

Both of these were shot with the same settings, but you can see there's a big quality difference. (Sorry about the size - it needed to be a 100% crop to make the difference as clear as possible.)

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Being that this is a library, there's always boxes of books from storage around and I used a couple of those as supports/weights to hold the boards in place. They're pretty much perfect building materials; since they're so heavy not even the heaviest or bulkiest book will shift the cradle during scanning. You can't see them in this photo, but just outside my office I have some pretty substantial ramparts and parapets constructed out of a dozen or more boxes of books. Mongol hordes, beware!

[Misty]

Oh yes, and I should probably include a sample image! I sent Dan a bunch that I think he's going to be posting soon, but here's a page from the book I was just scanning this morning, the one you can see in the photos. I don't use Scan Tailor much because I work primarily with handwritten documents, so this is a colour image processed in Adobe Camera Raw and Photoshop.

This is a page from a financial register dealing with the Penman Manufacturing Co.'s imported labour (mainly from England); it's part of a few books that I think are going to be really valuable to genealogists, because it has information on the ships they came in on and the like.

[rob]

Those are some great images from a very simple and easy scanner!

So... is "PROPERTY OF PARIS HISTOЯICAL SOCIETY" really stamped on every single page, both sides, of that document?

--Rob

[daniel_reetz]

Oh yes, and I should probably include a sample image! I sent Dan a bunch that I think he's going to be posting soon,

Yes- putting the finishing touches on that post tomorrow evening. Thanks again.

You are really pushing the limits of image quality with these compact cameras -- fantastic work. I'm particularly struck by your white/black background contrast reduction example.

[Misty]

Thanks, Dan! Yes, the quality improvement from the black background is fairly dramatic.

I have a bit of an advantage over some other users in that the G10 I'm using has much better quality than most other compact digicams - not equal to an APS-C, or even a Micro Four Thirds, but a good several steps above average compacts.

I do think I've been able to get most of the quality possible out of it, but I think I can improve a little more with proper lighting. Right now the only lighting I'm using is the room's overhead light - so it's a miracle I'm able to get a mostly even illumination, and even then I need to use ACR's graduated filter to even up the illumination on larger items. If you check the EXIF there, you can see I'm having to expose images for a half-second to get enough light for an appropriately bright image and that brings its own problems; with proper lighting I'll be able to get shutter speeds down to something more manageable, and that will also give me more options for aperture.

Those are some great images from a very simple and easy scanner!

So... is "PROPERTY OF PARIS HISTOЯICAL SOCIETY" really stamped on every single page, both sides, of that document?

--Rob

Thanks, Rob.

Not on every page, but several times throughout the book. Luckily, they don't do that anymore.

[Antoha-spb]

Hmmmm..... "Forty Creek" - never tasted but that must be a good choice

[Misty]

Following up on reflections, I was noticing something else recently that hadn't occurred to me before - reflections from the facing page. Take a look at these samples:

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- With black construction paper backing facing page, eliminating reflections

You can see that the first page is brighter, because light is bouncing off the page it's facing and reflecting at the page being shot. I think that changing the angle would change this; I don't have too much leeway in angles right now to prevent it, but it's worth keeping in mind. Masking out the other page is impractical, both because an ideal scanner would do two pages at a time (I only have one camera), and because the gutter in most books will cause the black paper to cast a shadow. This notebook only worked with it because of its thin flexible spine.

Edit: Antona, I've never actually tried Forty Creek. We have a liquour store nearby and their boxes are good for heavy books.

[Misty]

I wanted to follow up on the contrast issue brought up earlier, so I took a large number of samples to examine exactly what's going on. Here's what I found. First, here's the photo I'm using as a sample, in an ideal colour-corrected representation:

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Next, some JPEGs straight out of the camera showing uncorrected results. All images were shot at f/4.5 at 0.4s, ISO 80.

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Black backing on both sides of the cradle

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White backing under photo, black backing on reverse

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White backing on both sides of cradle

At a glance, you can see that the contrast is mostly similar in the first two, but very washed out in the third. Here's their histograms:

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Full black

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White + black mix

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All white

It's clear that the all-white image is being overexposed, contributing to the washed out look. However, even if I compensate for that:

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It becomes evident that the all-white background version is still looking too bright in the dark areas. It looks like the problem is reflection from the cradle itself - a bright cradle is reflecting light onto the other side of the cradle, resulting in brighter dark tones.

The all-black version also exhibits less visible noise. The following two examples are full-sized crops enlarged a bit, taken from the raws, with the same processing applied to each and noise filtering turned off.

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All black background

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All white background

The noise may partially be due to my original hypothesis about light being reflected into the lens from the background, because if you compare these shots from the all-black and black opposite, white facing versions:

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There's colour artifacting showing up in the version with a white background facing the camera, even though it has the same contrast thanks to the black background opposite the photo. You can also see that the all-black background version has visibly lower luma noise.

This is irrelevant to anyone not shooting raw, but I've also found that the versions with black under the photo itself provide better results in pumping up the blacks, which is necessary in this environment to obtain a lifelike level of dark colour when shooting documents. The all-white background version requires a much higher setting, and ends up with worse results.

To summarize the tl;dr version:

- A black background under the item being shot reduces noise, resulting in a better image
- A black background opposite the object being shot reduces light reflections, resulting in better contrast

[GreenLoco]

So... is "PROPERTY OF PARIS HISTOЯICAL SOCIETY" really stamped on every single page, both sides, of that document?

--Rob

Thanks, Rob.

Not on every page, but several times throughout the book. Luckily, they don't do that anymore.

I just signed-up so this may have been noted before.

To eliminate info from the reverse side of pages (at least when using a flat bed scanner) showing though to the front side, put a sheet of black paper between the page and the rest of the book (or scanner cover if it is a single sheet).

I have not started to build my book scanner yet (I haven't even purchased a camera) but I would think this same technique would work for a book scanner. Maybe someone could test it out and see if it works ?

- John

[univurshul]

I just signed-up so this may have been noted before.

To eliminate info from the reverse side of pages (at least when using a flat bed scanner) showing though to the front side, put a sheet of black paper between the page and the rest of the book (or scanner cover if it is a single sheet).

I have not started to build my book scanner yet (I haven't even purchased a camera) but I would think this same technique would work for a book scanner. Maybe someone could test it out and see if it works ?

- John

Yes. And depending on the quality of the scan you're going for, almost all of that is eliminated by the time it hits Scan Tailor anyway. If you're going after full color/grayscale reproduction, the black sheet between pages works. Although, I've seen my lights at 3800 lumens penetrate a sheet of paper and illuminate the backside of the page as well. Depends on the paper consistency and your lumens + the aforementioned technique.