Book scanning 300dpi vs 600dpi

paxomen · 07-13-2015, 07:15 PM

Hi all

I'm having a wonder about this and hoping for some help.

I have a Fujitsu Scansnap, and I have chopped three hundred novels (no images), and scanned into Scansnap scanner at Best Mode (Color & Grayscale 300 dpi, Monochrome 600 dpi).

Normal Mode - Color & Grayscale 150 dpi, Monochrome 300 dpi
Better Mode - Color & Grayscale 200 dpi, Monochrome 400 dpi
Best Mode - Color & Grayscale 300 dpi, Monochrome 600 dpi
Excellent Mode - Color & Grayscale 600 dpi, Monochrome 1200 dpi

My Scansnap also scans at excellent mode, but this is very slow, and the file size is huge.

The 300dpi seems fine both on my 6 inch Kindle 2nd gen, and on my iPad Air. I wish to read the pdfs rather than convert into mobi ising OCR etc

I have a few questions for expert MR readers:

If I am reading pdf standard novels (no pics):
1) Is Best Mode - Color & Grayscale 300 dpi, Monochrome 600 dpi sufficient?
2) If I want to future-proof the pdf-scanned-books, do I need to scan at excellent mode too. Do you antipate it is useful to instead capture them at excellent mode because of future e-readers and tablets that are yet to be released?

Any help is appreciated because I am running out of space and wish to recycle the 300 detroyed books, and don't really wish to scan them all a second time but more slowly just to get them in 600dpi unless absolutely neccessary.

Many thanks for any advice which can be offered.

Turtle91 · 07-14-2015, 01:41 AM

Hi Paxomen, welcome to MR!

There was alot of discussion about the best resolution to scan books over at DIYBookScanner.org. IIRC the consensus was 300dpi color/grayscale was sufficient.

If you truly wish to future proof them, I would highly recommend performing some kind of OCR even though it does take more time to ensure a good final product. Who can say how long PDFs are going to be around and you would eventually have to OCR to get it into a usable/convertible format. Text with basic markup (ie html/epub) is easy to store, small file size, packages everything in one file, and is easily converted to just about any other format.

Cheers,

Toxaris · 07-14-2015, 02:40 AM

It varies on the book. The fontsize and paper have a big influence on the quality. I find that my OCR errors drop significantly when I scan at 400dpi grayscale/color instead of 300dpi grayscale/color. Of course for books with big letters the increase is not as much, but for massmarket paperbacks with small letters I have up to 80% less OCR errors. Keep in mind that ABBYY is already doing a great job at 300dpi.

There is no golden rule, it really depends on the source. I scan at 400dpi, because it is only a bit slower and not much bigger.

Turtle91 · 07-14-2015, 11:15 AM

I know you mentioned you are using your scansnap to scan pages and were worried about the amount of time it takes to scan increasing quite a bit with higher resolutions. I thought it might interest you, or others reading, to learn about the benefits of a camera....

At the DIYBookScanner site I linked above you can see how they use cheap inexpensive cameras to simply take a photo of each page. An 8"x10" image (page size) at 300 ppi is 2400x3000 pixels, which is only 7.2 megapixels. A very basic camera can easily meet that requirement. If your page is smaller than 8x10 (or your camera has more megapixels) then you get a higher dpi count - and it doesn't take any longer to snap the picture.

They have systems set up where you can "scan" 1200 -ish pages per hour (about 3 seconds per page) - and it is completely Non-Destructive. They also have free software that takes those images, sorts, preps, and saves as pdf...or allows OCR if you are so inclined.

Hope that helps someone!

Cheers,

paxomen · 07-23-2015, 06:59 PM

Many thanks for the advice Turtle91, and Toxaris. I took your points about OCR. I have OCR'd them as well, so can change formats as needed.

Interesting that 400dpi reduced errors a lot.

I've noticed the option i use:

Best Mode - Color & Grayscale 300 dpi, B&W 600 dpi

since I've been scanning in B&W it must have got 600 dpi!

I guess the option below is not really likely to be needed for reading novels:
Excellent Mode - Color & Grayscale 600 dpi, Monochrome 1200 dpi

Toxaris · 07-24-2015, 01:45 AM

Well, the 400dpi I use is for color/grayscale, not B&W.

07-13-2015, 07:15 PM	#1
paxomen Junior Member Posts: 2 Karma: 10 Join Date: Jul 2015 Device: Kindle	Book scanning 300dpi vs 600dpi Hi all I'm having a wonder about this and hoping for some help. I have a Fujitsu Scansnap, and I have chopped three hundred novels (no images), and scanned into Scansnap scanner at Best Mode (Color & Grayscale 300 dpi, Monochrome 600 dpi). Normal Mode - Color & Grayscale 150 dpi, Monochrome 300 dpi Better Mode - Color & Grayscale 200 dpi, Monochrome 400 dpi Best Mode - Color & Grayscale 300 dpi, Monochrome 600 dpi Excellent Mode - Color & Grayscale 600 dpi, Monochrome 1200 dpi My Scansnap also scans at excellent mode, but this is very slow, and the file size is huge. The 300dpi seems fine both on my 6 inch Kindle 2nd gen, and on my iPad Air. I wish to read the pdfs rather than convert into mobi ising OCR etc I have a few questions for expert MR readers: If I am reading pdf standard novels (no pics): 1) Is Best Mode - Color & Grayscale 300 dpi, Monochrome 600 dpi sufficient? 2) If I want to future-proof the pdf-scanned-books, do I need to scan at excellent mode too. Do you antipate it is useful to instead capture them at excellent mode because of future e-readers and tablets that are yet to be released? Any help is appreciated because I am running out of space and wish to recycle the 300 detroyed books, and don't really wish to scan them all a second time but more slowly just to get them in 600dpi unless absolutely neccessary. Many thanks for any advice which can be offered. Last edited by paxomen; 07-13-2015 at 07:22 PM.

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07-14-2015, 01:41 AM	#2
Turtle91 A Hairy Wizard Posts: 3,136 Karma: 18727091 Join Date: Dec 2012 Location: Charleston, SC today Device: iPhone 11/X/6/iPad 1,2,Air & Air Pro/Surface Pro/Kindle PW & Fire	Hi Paxomen, welcome to MR! There was alot of discussion about the best resolution to scan books over at DIYBookScanner.org. IIRC the consensus was 300dpi color/grayscale was sufficient. If you truly wish to future proof them, I would highly recommend performing some kind of OCR even though it does take more time to ensure a good final product. Who can say how long PDFs are going to be around and you would eventually have to OCR to get it into a usable/convertible format. Text with basic markup (ie html/epub) is easy to store, small file size, packages everything in one file, and is easily converted to just about any other format. Cheers,

07-14-2015, 02:40 AM	#3
Toxaris Wizard Posts: 4,520 Karma: 121692313 Join Date: Oct 2009 Location: Heemskerk, NL Device: PRS-T1, Kobo Touch, Kobo Aura	It varies on the book. The fontsize and paper have a big influence on the quality. I find that my OCR errors drop significantly when I scan at 400dpi grayscale/color instead of 300dpi grayscale/color. Of course for books with big letters the increase is not as much, but for massmarket paperbacks with small letters I have up to 80% less OCR errors. Keep in mind that ABBYY is already doing a great job at 300dpi. There is no golden rule, it really depends on the source. I scan at 400dpi, because it is only a bit slower and not much bigger.

07-14-2015, 11:15 AM	#4
Turtle91 A Hairy Wizard Posts: 3,136 Karma: 18727091 Join Date: Dec 2012 Location: Charleston, SC today Device: iPhone 11/X/6/iPad 1,2,Air & Air Pro/Surface Pro/Kindle PW & Fire	I know you mentioned you are using your scansnap to scan pages and were worried about the amount of time it takes to scan increasing quite a bit with higher resolutions. I thought it might interest you, or others reading, to learn about the benefits of a camera.... At the DIYBookScanner site I linked above you can see how they use cheap inexpensive cameras to simply take a photo of each page. An 8"x10" image (page size) at 300 ppi is 2400x3000 pixels, which is only 7.2 megapixels. A very basic camera can easily meet that requirement. If your page is smaller than 8x10 (or your camera has more megapixels) then you get a higher dpi count - and it doesn't take any longer to snap the picture. They have systems set up where you can "scan" 1200 -ish pages per hour (about 3 seconds per page) - and it is completely Non-Destructive. They also have free software that takes those images, sorts, preps, and saves as pdf...or allows OCR if you are so inclined. Hope that helps someone! Cheers,

07-23-2015, 06:59 PM	#5
paxomen Junior Member Posts: 2 Karma: 10 Join Date: Jul 2015 Device: Kindle	Many thanks for the advice Turtle91, and Toxaris. I took your points about OCR. I have OCR'd them as well, so can change formats as needed. Interesting that 400dpi reduced errors a lot. I've noticed the option i use: Best Mode - Color & Grayscale 300 dpi, B&W 600 dpi since I've been scanning in B&W it must have got 600 dpi! I guess the option below is not really likely to be needed for reading novels: Excellent Mode - Color & Grayscale 600 dpi, Monochrome 1200 dpi

07-24-2015, 01:45 AM	#6
Toxaris Wizard Posts: 4,520 Karma: 121692313 Join Date: Oct 2009 Location: Heemskerk, NL Device: PRS-T1, Kobo Touch, Kobo Aura	Well, the 400dpi I use is for color/grayscale, not B&W.

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