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

ix500 workflow. Scan directly to grayscale/bw or do it in photoshop postprocessing?

Book scanning methods that involve taking books apart.
Scanallthebooks
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ix500 workflow. Scan directly to grayscale/bw or do it in photoshop postprocessing?

Post by Scanallthebooks » 07 Dec 2016, 11:26

I've got an ix500, is there any benefit in scanning in color and then afterwords converting to gray scale/bw in photoshop vs scanning them directly in grey scale/bw using the scansnap software? I think it might be possible to achieve better quality if you do the post processing in photoshop.

cday
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Re: ix500 workflow. Scan directly to grayscale/bw or do it in photoshop postprocessing?

Post by cday » 07 Dec 2016, 14:49

Scanallthebooks wrote:I've got an ix500, is there any benefit in scanning in color and then afterwords converting to gray scale/bw in photoshop vs scanning them directly in grey scale/bw using the scansnap software? I think it might be possible to achieve better quality if you do the post processing in photoshop.
I would suspect that it would probably be best to scan in grayscale, after experimenting to find the optimum scanner settings, and then optionally further enhance the images in Photoshop as necessary.

I'm reasoning that lower quality initial scans may contain less information, limiting the quality that can ultimately be obtained...

rkomar
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Re: ix500 workflow. Scan directly to grayscale/bw or do it in photoshop postprocessing?

Post by rkomar » 07 Dec 2016, 16:21

There is a small advantage to scanning in colour; you can define yourself how the conversion from colour to greyscale is done. It's theoretically possible that different colours will produce the same greyscale value in one conversion scheme, thereby looking the same in the output. A different scheme might produce different greyscale values for the two colours. In practice, I haven't noticed this issue when scanning and don't worry about it myself. Doing side-by-side checks on every scan conversion to see if it looks optimal would be too onerous to bother with.

duerig
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Re: ix500 workflow. Scan directly to grayscale/bw or do it in photoshop postprocessing?

Post by duerig » 07 Dec 2016, 18:34

I never saw much of a benefit to scanning in greyscale on the camera. And I also found that it seemed to slow down the scanning cycle somewhat. When just taking normal pictures, I find that the cameras work as fast as I can turn the pages. When using greyscale, I had to wait on the camera sometimes.

-Jonathon Duerig

cday
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Re: ix500 workflow. Scan directly to grayscale/bw or do it in photoshop postprocessing?

Post by cday » 07 Dec 2016, 18:57

duerig wrote:I never saw much of a benefit to scanning in greyscale on the camera. And I also found that it seemed to slow down the scanning cycle somewhat. When just taking normal pictures, I find that the cameras work as fast as I can turn the pages. When using greyscale, I had to wait on the camera sometimes.
But that's using a camera not a flatbed/sheet fed scanner...

Thinking about it, as the sensor in both cases is an RGB sensor, producing a grayscale output does presumably require some processing, but I suspect that the processor in a flatbed scanner is likely to be substantially faster than that in a camera.

So some relative tests with the ix500 might be worthwhile.

Scanallthebooks
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Re: ix500 workflow. Scan directly to grayscale/bw or do it in photoshop postprocessing?

Post by Scanallthebooks » 08 Dec 2016, 18:31

Thanks for all the answers guys.
cday wrote:I would suspect that it would probably be best to scan in grayscale, after experimenting to find the optimum scanner settings, and then optionally further enhance the images in Photoshop as necessary.

I'm reasoning that lower quality initial scans may contain less information, limiting the quality that can ultimately be obtained...
The ix500 scans both color and greyscale @ 600dpi, so I'm assuming the "quality" is the same. But that's what I'm uncertain about...if you choose greyscale, does it scan in greyscale or does it scan in color and then automatically apply some postprocessing greyscale adjustment?

I'll see if I can run a page through the scanner twice, once scanning in color and once scanning in greyscale. I'll convert the color scan to greyscale using photoshop and upload both images so we can compare.

EDIT: If you guys want me to do any other tests let me know.

Scanallthebooks
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Re: ix500 workflow. Scan directly to grayscale/bw or do it in photoshop postprocessing?

Post by Scanallthebooks » 09 Dec 2016, 07:59

Here's a comparison, all scans @ 600 dpi, lowest compression:

Reduced size:
https://www.dropbox.com/s/834l13p3m9pi9 ... d.png?dl=0

Full size:
https://www.dropbox.com/s/swrvv4ozl59z7 ... e.png?dl=0

I think I prefer Adobe's conversion.

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Re: ix500 workflow. Scan directly to grayscale/bw or do it in photoshop postprocessing?

Post by cday » 09 Dec 2016, 08:27

Test_page.png
That page is on coloured paper and you just want good quality text on a white background?

If you're happy to scan at 600DPI, you might try scanning in black and white... But that coloured background might not convert cleanly to pure white, in which case some enhancement of the colour scan followed to converion to black and white 1-bit might be the answer, and also give you much smaller file sizes if you save as TIFF with CCITT G4 'Fax' compression, for example.

EDit:

Another option would be to adjust the scanner settings to try to obtain a black and white scan with a clean white background directly...

Scanallthebooks
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Re: ix500 workflow. Scan directly to grayscale/bw or do it in photoshop postprocessing?

Post by Scanallthebooks » 09 Dec 2016, 10:14

cday wrote: That page is on coloured paper and you just want good quality text on a white background?
I'm sorry if I'm a bit confusing, initially I was undecided on whether I wanted to do greyscale or bw, but I'm coming around to greyscale because I think it looks better. Unfortunately there is no standardization of how to output books so we all have to decide individually how we want the final ebook to look like.

However my initial question was just, is it better to scan directly to either greyscale or bw...or to scan in color and then, afterwards, use photoshop to convert to either greyscale or bw? People were not really certain and just suspecting stuff so I decided to test it out and post the results here so maybe others can benefit.
cday wrote:If you're happy to scan at 600DPI, you might try scanning in black and white... But that coloured background might not convert cleanly to pure white
Yeah, that's a big problem! In fact the ix500 is able to scan bw @ 1200 dpi which results in this:

https://www.dropbox.com/s/s3qpv79febcuwm0/bw.png?dl=0
cday wrote:in which case some enhancement of the colour scan followed to converion to black and white 1-bit might be the answer, and also give you much smaller file sizes if you save as TIFF with CCITT G4 'Fax' compression, for example.
I took my previous color scan @ 600 dpi, converted it to greyscale, played with the levels and finally converted it to bitmap mode. Saving as TIFF this was the result:

https://www.dropbox.com/s/7v135wf6mrswr ... f.tif?dl=0

(I couldn't find any CCITT G4 Fax compression setting in Photoshop, so used LZW compression. File size ~100KB)
cday wrote:Another option would be to adjust the scanner settings to try to obtain a black and white scan with a clean white background directly...
The software is very simple, when you're scanning bw you can't even save the result directly to an image format but have to save it to a PDF (i've been exporting the images above using adobe acrobat). But there are options for increasing the brightness and increasing text contrast so I'll play with those options and post the results.

cday
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Re: ix500 workflow. Scan directly to grayscale/bw or do it in photoshop postprocessing?

Post by cday » 09 Dec 2016, 10:57

Scanallthebooks wrote:
cday wrote: That page is on coloured paper and you just want good quality text on a white background?
I'm sorry if I'm a bit confusing, initially I was undecided on whether I wanted to do greyscale or bw, but I'm coming around to greyscale because I think it looks better. Unfortunately there is no standardization of how to output books so we all have to decide individually how we want the final ebook to look like.
My question was just about what you wanted your final output page to look like?
Scanallthebooks wrote:
cday wrote:Another option would be to adjust the scanner settings to try to obtain a black and white scan with a clean white background directly...
The software is very simple, when you're scanning bw you can't even save the result directly to an image format but have to save it to a PDF (i've been exporting the images above using adobe acrobat). But there are options for increasing the brightness and increasing text contrast so I'll play with those options and post the results.
Those options to adjust brightness and contrast, and any similar options if there should be any, are what I meant: if you do want a white page, it might with careful adjustment be possible to obtain one directly, otherwise adjusting the settings should enable you to obtain a better colour or grayscale image to enhance in PhotoShop...

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