Re: [O] [OT] Scanning for archiving
TP wing...@gmail.com writes: Apparently the S1500's are supported on Linux via Sane (http://www.sane-project.org/sane-backends.html#S-FUJITSU). Don't see any mention of the S1300 (but it probably also works?). I can confirm that the S1300 works well with Linux. Best, Matt
Re: [O] [OT] Scanning for archiving
On Sun, 6 Nov 2011 22:14:54 -0800, TP wing...@gmail.com wrote: On Sun, Nov 6, 2011 at 1:59 PM, Pieter Praet pie...@praet.org wrote: On Sat, 5 Nov 2011 16:35:11 -0700, Samuel Wales samolog...@gmail.com wrote: I used to find that 8-bit 75dpi was legible and small. True. It all depends on why you're scanning them in the first place. 75dpi is fine when scanning with collaboration/quick-reference in mind, but for archival/backup purposes (i.e. absolute peace of mind when your whole collection of dead trees burns, drowns, or is simply disposed of) or OCR, you'll want to go with 600dpi and beyond. One common technique is to always scan 300dpi grayscale (or color) and use clever software to upsample to 600dpi bw (of course somehow segmenting scans into picture and text regions first. Upsampling defies the first law of thermodynamics? But seriously, after reading up a bit, I'm convinced :) Quite a manual process though... Could you recommend any (FOSS) software that does this automatically? What ADF scanners are out there for Linux that have high quality reliable ADF, [...] I wish I knew... If anyone on this list can think of a scanner whose ADF doesn't require constant babysitting, I'm betting it won't have a consumer-grade price tag. I've heard nice things about the Fujitsu ScanSnap S1500 (http://www.fujitsu.com/global/services/computing/peripheral/scanners/product/s1500/) and S1500M (http://www.fujitsu.com/global/services/computing/peripheral/scanners/product/s1500m/). About $450 or so from amazon. The S1300 is about half the price but also slower. Apparently the S1500's are supported on Linux via Sane (http://www.sane-project.org/sane-backends.html#S-FUJITSU). Don't see any mention of the S1300 (but it probably also works?). Peace -- Pieter
Re: [O] [OT] Scanning for archiving
Apologies for top-posting, but my comment is only inspired by the conversation and doesn't exactly build on it, so here we go. I use predominantly pdf in scanning, for one main reason only - it handles *metadata* nicely (with gscan2pdf). This is nice for searching later. When playing with DjVu, I didn't find an easy way to amend metadata - is there any good working method and tools to recommend for adding metadata for DjVu files? Thanks. Pieter Praet pie...@praet.org writes: On Mon, 7 Nov 2011 18:44:24 +0100, Karl Voit devn...@karl-voit.at wrote: Hi! Inspired by «Total Recall»[3], a book of two MS Research guys, I started life logging on my own two months ago. Dammit, that's been on my reading list for almost 2 years now, and *still* it isn't available in ebook format. One would think they'd walk their talk [1], no? [...] * Pieter Praet pie...@praet.org wrote: Using PDF for scanned documents results in *huge* files with a seriously disappointing image quality. I can not copy that at all: , | vk@gary ~2d % l 2011-11-02_13-22-45.png | -rw--- 1 vk vk 103150 2011-11-02 13:22 2011-11-02_13-22-45.png | vk@gary ~2d % convert 2011-11-02_13-22-45.png 2011-11-02_13-22-45.pdf | vk@gary ~2d % l 2011-11-02_13-22-45.pdf | -rw-r--r-- 1 vk vk 96457 2011-11-07 18:12 2011-11-02_13-22-45.pdf | vk@gary ~2d % ` In this example, the compression of PDF is much better than the original PNG one. PDF is only a container format. The conversion to PDF has indeed reduced the filesize, but not for the reasons you might think: If you don't explicitly provide ImageMagick's `convert' with a compression level (`-quality' option), it will use a default of 75%. Thus I (perhaps incorrectly) infer that you've just lost 25% of the image quality for a meager 7% reduction in filesize. I do admit that the whole quality vs. filesize statement I made regarding using PDF for scanned documents wasn't entirely correct: I cut some corners. The real issue is that most folks use their scanner software to save directly to PDF, and for some reason, scanner software (especially the proprietary variety) predominantly uses JPEG compression as default when saving to PDF. JPEG was developed for storing images with smooth transitions and a high bit depth (i.e. photographs), not hard transitions and a low bit depth (i.e. documents), so you're likely to suffer a noticeable degradation in text quality, even when using 1:1 JPEG compression. You're using PNG compression though, so the whole JPEG deal doesn't apply. So, that just leaves the neverending stream of PDF security issues :) Consider storing your scans in DjVu format [1], which was developed specifically for this purpose. PDF is a common standard whereas DjVu is something I - as an advanced computer user - never faced before in real life. I am not sure whether any of my computers can handle DjVu files at all. How about the Million Book Project / Universal Digital Library [2] ? Even though every computing device is most likely to support PDF, their collection is only available in TIFF and DjVu format. The list of participants and partners [3] (not to mention the magnitude and cost of their undertaking) is reason enough (for me, at least) to assume that DjVu is deemed to be rather future-proof. I'm guessing ISO standardization will be only a matter of time. The goals of DjVu sound great but I get everything with PDF too. Although I like the idea of OGG Vorbis, I re-ripped all my CDs using mp3 again because I could not use many music devices or music management software packages. Ahhh, VHS vs. Betamax, over and over again... Companies only succeed in getting everyone stuck with mediocre tools if we allow them to. You don't *need* all devices/software to support the superior format. Just get the ones that do (if there are any...), try to enlighten the people in you monkeysphere [4], and then let the free market do its work. Joe Average Consumer will eventually follow (unless pornography is at stake, apparently), and the industry will be right on his tail. I stick to the format *any* computer can handle without special software products. [...] Somehow this implies that *every* computer is infected with Adobe's malware. I find that rather disconcerting, to be honest :D [...] And I do think that I get a higher chance of being able to read my documents twenty years from now. For your sake, I hope you're right! For scanned images I'd prefer PNG instead but the OS X Software of my OfficeJet offers me the ability to generate PDF files where an OCR software adds a searchable text layer above the scanned text. This is *very* important to me since I am able to do full text search on the content of my archived documents. May be a bit less convenient in daily usage, but you could stick to your preference of keeping all your scans in PNG format by keeping the OCR output in a
Re: [O] [OT] Scanning for archiving
(I enjoy the OT discussion here and hope that no one gets upset because of it on this ML ...) * Pieter Praet pie...@praet.org wrote: On Mon, 7 Nov 2011 18:44:24 +0100, Karl Voit devn...@karl-voit.at wrote: Hi! Inspired by «Total Recall»[3], a book of two MS Research guys, I started life logging on my own two months ago. Dammit, that's been on my reading list for almost 2 years now, and *still* it isn't available in ebook format. One would think they'd walk their talk [1], no? I personally do not want to read a book other than on paper - for now. Annotating, highlighting and placing different kind of postit-marks still does not have its digital representations I would like to see :-( I recommend [1] mainly because of its chapters upon how to start and best practices. Previous chapters are future visions and motivation I do think that we do not need (any more). Besides the fact that the raw paper cut offers horrible handling usability it is quite easy and fast to read. | -rw--- 1 vk vk 103150 2011-11-02 13:22 2011-11-02_13-22-45.png | vk@gary ~2d % convert 2011-11-02_13-22-45.png 2011-11-02_13-22-45.pdf | vk@gary ~2d % l 2011-11-02_13-22-45.pdf | -rw-r--r-- 1 vk vk 96457 2011-11-07 18:12 2011-11-02_13-22-45.pdf The conversion to PDF has indeed reduced the filesize, but not for the reasons you might think: If you don't explicitly provide ImageMagick's `convert' with a compression level (`-quality' option), it will use a default of 75%. Thus I (perhaps incorrectly) infer that you've just lost 25% of the image quality for a meager 7% reduction in filesize. Ah, thanks for the clarification! This is indeed interesting fact. Still: I did never recognize any problem with the 75% result though :-) It is clearly readable and zoomable on screen and produces very good results when printed out again. The real issue is that most folks use their scanner software to save directly to PDF, and for some reason, scanner software (especially the proprietary variety) predominantly uses JPEG compression as default when saving to PDF. OK, this is interesting (again). So I took a closer look on the result files my HP OfficeJet is producing when I scan to PDF. «pdfimages» and «file» shows me that in the PDF files there are embedded «Netpbm PPM rawbits image data» image files.[6] Another format I was not confronted with until now. Seems to be a pixel-based compressed and standardized format. This is fine to me so far. JPEG would be horrible ... JPEG was developed for storing images ... Part of my job was to explain first term students the difference, advantages and disadvantages regarding to file formats like JPEG and PNG. I can tell stories ... You're using PNG compression though, so the whole JPEG deal doesn't apply. Oh, this was just an example of how «convert *png *pdf» reduces file size. (Which was corrected by you.) I usually scan directly into «searchable PDF» which the HP Scan offers me. My OfficeJet even allows me to simply put pages onto the ADF, press (more) buttons (than necessary) on the printer itself and without any further interaction, the searchable PDF files are placed into a folder of my choice, using my file name convention containing a time stamp of the scan process. This is kinda neat :-) So I do not even need to turn on my TFT for scanning stuff. (My Mac Mini is on 24/7 anyway.) So, that just leaves the neverending stream of PDF security issues :) I do not publish blacked out PDF files. Or do you mean something else? There is no security related issue that worries me for now. I have to protect my data anyhow from being accessed by anyone else, independent of the file formats. Consider storing your scans in DjVu format [1], which was developed specifically for this purpose. PDF is a common standard whereas DjVu is something I - as an advanced computer user - never faced before in real life. I am not sure whether any of my computers can handle DjVu files at all. How about the Million Book Project / Universal Digital Library [2] ? Well they are that big that they could even use a proprietary format on purpose too. With valid arguments. They have different requirements than I have. Even though every computing device is most likely to support PDF, their collection is only available in TIFF and DjVu format. TIFF is a perfectly wide spread standard I would choose for uncompressed raw data to store to. The automotive industry here is using TIFF images for many purposes outside of CAD design. I would not choose TIFF for long time archive format for my personal data. I'm guessing ISO standardization will be only a matter of time. Hope so. Looks like a promising format. Although I like the idea of OGG Vorbis, I re-ripped all my CDs using mp3 again because I could not use many music devices or music management software packages. Ahhh, VHS vs. Betamax, over and over again... ... and my beloved MiniDisc vs. some other formats :-) Yes. And
Re: [O] [OT] Scanning for archiving
* Karl Voit devn...@karl-voit.at wrote: Inspired by «Total Recall»[3], a book of two MS Research guys, I started life logging on my own two months ago. For this purpose I bought an HP OfficeJet Pro 8500A Plus which costs € 250 and has a decent scanner. Is can scan and print full duplex. The scanner as a 30 page ADF which is quite reliable when the paper was not bend or stapled before. Addendum: I just ordered a ScanSnap S1500M[4] which was also used by the authors of «Total Recall». The HP OfficeJet Pro ADF is OK for occasional scanning. For big scan jobs, the HP Scan software as well as the ADF reliability is not sufficient I am afraid. Approx. 15-20% of the pages are not scanned because of multiple pages were scanned at once. The HP Scan software is not very user friendly: no visualization of the total sum of scanned pages per job, no auto-correction of scan skew, no auto delete of empty pages, far too few keyboard shortcuts for basic functions, ... Reading quite some product reviews I am confident that the ScanSnap is able to provide a more reliable and easy to use scan experience for large scan jobs. After I scanned all of my current papers, I will probably sell the ScanSnap and use the scanner of the OfficeJet Pro again. 4. http://scanners.fcpa.fujitsu.com/scansnapit/scansnap-s1500m.php -- Karl Voit
Re: [O] [OT] Scanning for archiving
On Mon, 7 Nov 2011 18:44:24 +0100, Karl Voit devn...@karl-voit.at wrote:
Hi!
Inspired by «Total Recall»[3], a book of two MS Research guys, I
started life logging on my own two months ago.
Dammit, that's been on my reading list for almost 2 years now, and
*still* it isn't available in ebook format. One would think they'd walk
their talk [1], no?
[...]
* Pieter Praet pie...@praet.org wrote:
Using PDF for scanned documents results in *huge* files with a seriously
disappointing image quality.
I can not copy that at all:
,
| vk@gary ~2d % l 2011-11-02_13-22-45.png
| -rw--- 1 vk vk 103150 2011-11-02 13:22 2011-11-02_13-22-45.png
| vk@gary ~2d % convert 2011-11-02_13-22-45.png 2011-11-02_13-22-45.pdf
| vk@gary ~2d % l 2011-11-02_13-22-45.pdf
| -rw-r--r-- 1 vk vk 96457 2011-11-07 18:12 2011-11-02_13-22-45.pdf
| vk@gary ~2d %
`
In this example, the compression of PDF is much better than the
original PNG one. PDF is only a container format.
The conversion to PDF has indeed reduced the filesize, but not for the
reasons you might think: If you don't explicitly provide ImageMagick's
`convert' with a compression level (`-quality' option), it will use a
default of 75%. Thus I (perhaps incorrectly) infer that you've just
lost 25% of the image quality for a meager 7% reduction in filesize.
I do admit that the whole quality vs. filesize statement I made
regarding using PDF for scanned documents wasn't entirely correct:
I cut some corners.
The real issue is that most folks use their scanner software to save
directly to PDF, and for some reason, scanner software (especially the
proprietary variety) predominantly uses JPEG compression as default when
saving to PDF.
JPEG was developed for storing images with smooth transitions and a high
bit depth (i.e. photographs), not hard transitions and a low bit depth
(i.e. documents), so you're likely to suffer a noticeable degradation in
text quality, even when using 1:1 JPEG compression.
You're using PNG compression though, so the whole JPEG deal doesn't apply.
So, that just leaves the neverending stream of PDF security issues :)
Consider storing your scans in DjVu format
[1], which was developed specifically for this purpose.
PDF is a common standard whereas DjVu is something I - as an
advanced computer user - never faced before in real life. I am not
sure whether any of my computers can handle DjVu files at all.
How about the Million Book Project / Universal Digital Library [2] ?
Even though every computing device is most likely to support PDF, their
collection is only available in TIFF and DjVu format.
The list of participants and partners [3] (not to mention the magnitude
and cost of their undertaking) is reason enough (for me, at least) to
assume that DjVu is deemed to be rather future-proof.
I'm guessing ISO standardization will be only a matter of time.
The goals of DjVu sound great but I get everything with PDF too.
Although I like the idea of OGG Vorbis, I re-ripped all my CDs using
mp3 again because I could not use many music devices or music
management software packages.
Ahhh, VHS vs. Betamax, over and over again...
Companies only succeed in getting everyone stuck with mediocre tools if
we allow them to. You don't *need* all devices/software to support the
superior format. Just get the ones that do (if there are any...), try
to enlighten the people in you monkeysphere [4], and then let the free
market do its work. Joe Average Consumer will eventually follow (unless
pornography is at stake, apparently), and the industry will be right on
his tail.
I stick to the format *any* computer can handle without special
software products. [...]
Somehow this implies that *every* computer is infected with Adobe's
malware. I find that rather disconcerting, to be honest :D
[...] And I do think that I get a higher chance of
being able to read my documents twenty years from now.
For your sake, I hope you're right!
For scanned images I'd prefer PNG instead but the OS X Software of
my OfficeJet offers me the ability to generate PDF files where an
OCR software adds a searchable text layer above the scanned text.
This is *very* important to me since I am able to do full text
search on the content of my archived documents.
May be a bit less convenient in daily usage, but you could stick to your
preference of keeping all your scans in PNG format by keeping the OCR
output in a separate ASCII file:
#+begin_src sh
for i in $(ls ${HOME}/msg/paper/inbox/*.png) ; do
tesseract ${i} ${i}.txt
done
#+end_src
That way you can access your data even on text-only machines,
and full-text search is only a `grep' away.
And I plan to archive *all* of my documents. Really all of them.
Then you'll probably be interested in Joey Hess' git-annex [5] to keep
your archive versioned and in sync across all your devices.
Storage space does not matter (any more) to me since I have more
disk
Re: [O] [OT] Scanning for archiving
Hi! Inspired by «Total Recall»[3], a book of two MS Research guys, I started life logging on my own two months ago. For this purpose I bought an HP OfficeJet Pro 8500A Plus which costs € 250 and has a decent scanner. Is can scan and print full duplex. The scanner as a 30 page ADF which is quite reliable when the paper was not bend or stapled before. * Pieter Praet pie...@praet.org wrote: Using PDF for scanned documents results in *huge* files with a seriously disappointing image quality. I can not copy that at all: , | vk@gary ~2d % l 2011-11-02_13-22-45.png | -rw--- 1 vk vk 103150 2011-11-02 13:22 2011-11-02_13-22-45.png | vk@gary ~2d % convert 2011-11-02_13-22-45.png 2011-11-02_13-22-45.pdf | vk@gary ~2d % l 2011-11-02_13-22-45.pdf | -rw-r--r-- 1 vk vk 96457 2011-11-07 18:12 2011-11-02_13-22-45.pdf | vk@gary ~2d % ` In this example, the compression of PDF is much better than the original PNG one. PDF is only a container format. Consider storing your scans in DjVu format [1], which was developed specifically for this purpose. PDF is a common standard whereas DjVu is something I - as an advanced computer user - never faced before in real life. I am not sure whether any of my computers can handle DjVu files at all. The goals of DjVu sound great but I get everything with PDF too. Although I like the idea of OGG Vorbis, I re-ripped all my CDs using mp3 again because I could not use many music devices or music management software packages. I stick to the format *any* computer can handle without special software products. And I do think that I get a higher chance of being able to read my documents twenty years from now. For scanned images I'd prefer PNG instead but the OS X Software of my OfficeJet offers me the ability to generate PDF files where an OCR software adds a searchable text layer above the scanned text. This is *very* important to me since I am able to do full text search on the content of my archived documents. And I plan to archive *all* of my documents. Really all of them. Storage space does not matter (any more) to me since I have more disk space now already than I could possible fill with my lifetime paper correspondence. And I do think that my disk space continues to grow in future. I scan all docs @ 600dpi, predominantly gray-scale (only in colour when it's *really* necessary) and store in DjVu format, all using gscan2pdf [2]. Even at that seemingly overkill resolution, single-page documents are generally (if they aren't too grainy) only a few 100 KiB in size. My HP software uses 300 dpi per default and it is OK to me too. Funny side fact: grayscale scan document settings produces slightly larger files than colored ones. gscan2pdf also supports a number of OCR utils, but the UI for this is clumsy (aren't they all...), so you're better off using the CLI tools directly. Tesseract is recommended. I played around with ocropus, tesseract, ocroscript, hocr2pdf, exactimage, ppa:gezakovacs/pdfocr, ... to generate those sandwitch PDF documents (OCR text above the scanned images) on GNU/Linux. Unfortunately none of those (very cool projects) produced reliable results on my side. The results vary from «no error but overlay font size is incorrect and produces loss of layout» to «library error messages I can not read or handle». Whereas the HP OfficeJet bundles its OS X software with OCR from Readiris which produces perfect results even in different languages and using a usable user interface. NOTE: When attempting something like this, a fast scanner with a *reliable* automatic document feeder will help prevent premature hair loss ;) I have found several scanner products I was interested in: Canon imageFORMULA P-150: very small form factor with basic Linux support. Price tag starts with € 260. Neat form factor and very portable. Different version P-150m for Mac OS X. The authors of [3] use Fujitsu ScanSnap starting at € 400. I ended up with the Office Jet Pro (mentioned above) at € 250 because I got flatbed scanner *and* ADF-scanner *and* a full-duplex/full-color network printer with a very good price-per-printed-page-ratio (better than many laser printers!). And all of this with a cheaper price tag than any scan-only-product I was interested in. So far I am almost satisfied. «Almost»? Well, HP did a good job with this printer but they made only a 90% solution on almost all levels. Whereas 100% would be possible with small additional effort when creating the printer. But those resulting 90% are pretty usable. 3. http://qr.cx/sAHU -- Karl Voit
Re: [O] [OT] Scanning for archiving
On Sat, 5 Nov 2011 16:35:11 -0700, Samuel Wales samolog...@gmail.com wrote: I used to find that 8-bit 75dpi was legible and small. True. It all depends on why you're scanning them in the first place. 75dpi is fine when scanning with collaboration/quick-reference in mind, but for archival/backup purposes (i.e. absolute peace of mind when your whole collection of dead trees burns, drowns, or is simply disposed of) or OCR, you'll want to go with 600dpi and beyond. If using DjVu instead of PDF, the storage overhead will be negligible. What ADF scanners are out there for Linux that have high quality reliable ADF, [...] I wish I knew... If anyone on this list can think of a scanner whose ADF doesn't require constant babysitting, I'm betting it won't have a consumer-grade price tag. [...] are fast, [...] Pretty much all of them, these days. and work well with CLI tools? As long as it's supported by SANE [1], rats are entirely optional. Is OCR at the point where it is feasible using CLI? [...] Depends on how fancy the document layout is. For most documents worth scanning (let alone OCR'ing), it always has been. Also see OCRopus [2]. [...] Combining that with a new feature to have the Org agenda work with indexers (I participated in a discussion on that here a long while back) would be interesting. If you don't intend to create a perfect ASCII copy of the document, and your index is restricted to word occurrence/frequency, it'll do just fine. On 2011-11-05, Pieter Praet pie...@praet.org wrote: NOTE: When attempting something like this, a fast scanner with a *reliable* automatic document feeder will help prevent premature hair loss ;) ... [1] http://djvu.org/resources/whatisdjvu.php [2] http://gscan2pdf.sourceforge.net/ Peace -- Pieter [1] http://www.sane-project.org/sane-supported-devices.html [2] http://code.google.com/p/ocropus/
Re: [O] [OT] Scanning for archiving
On Sun, Nov 6, 2011 at 1:59 PM, Pieter Praet pie...@praet.org wrote: On Sat, 5 Nov 2011 16:35:11 -0700, Samuel Wales samolog...@gmail.com wrote: I used to find that 8-bit 75dpi was legible and small. True. It all depends on why you're scanning them in the first place. 75dpi is fine when scanning with collaboration/quick-reference in mind, but for archival/backup purposes (i.e. absolute peace of mind when your whole collection of dead trees burns, drowns, or is simply disposed of) or OCR, you'll want to go with 600dpi and beyond. One common technique is to always scan 300dpi grayscale (or color) and use clever software to upsample to 600dpi bw (of course somehow segmenting scans into picture and text regions first. What ADF scanners are out there for Linux that have high quality reliable ADF, [...] I wish I knew... If anyone on this list can think of a scanner whose ADF doesn't require constant babysitting, I'm betting it won't have a consumer-grade price tag. I've heard nice things about the Fujitsu ScanSnap S1500 (http://www.fujitsu.com/global/services/computing/peripheral/scanners/product/s1500/) and S1500M (http://www.fujitsu.com/global/services/computing/peripheral/scanners/product/s1500m/). About $450 or so from amazon. The S1300 is about half the price but also slower. Apparently the S1500's are supported on Linux via Sane (http://www.sane-project.org/sane-backends.html#S-FUJITSU). Don't see any mention of the S1300 (but it probably also works?).
[O] [OT] Scanning for archiving
Hi list, I just bought a scanner and started to scan important documents as a backup, and archiving them with meaningful metadata in orgmode files. Then a question came to mind - what dpi to use? I'm not really savvy when it comes to scanning or printing, and I want like a dpi that allows me to reprint the document at an acceptable quality later if necessary, but that also doesn't take that much space (600dpi pdfs take around 5MB). Any insights welcome, Thanks, Marcelo.
Re: [O] [OT] Scanning for archiving
Marcelo de Moraes Serpa celose...@gmail.com writes: I just bought a scanner and started to scan important documents as a backup, and archiving them with meaningful metadata in orgmode files. Then a question came to mind - what dpi to use? I'm not really savvy when it comes to scanning or printing, and I want like a dpi that allows me to reprint the document at an acceptable quality later if necessary, but that also doesn't take that much space (600dpi pdfs take around 5MB). Fax in fine mode has about 200dpi resolution. The raw scan should be in higher resolution (usually 2x-4x the target resolution depending on the document quality). The file to be archived then needs to be compressed (lossless compression is preferred, e.g. TIFF or PNG) and the bit depth reduced (black and white, usually). When making PDF files you need to make sure that the image data doesn't get re-coded (often into much inferior JPEG). For documents containing (color) images it is often preferrable to separately treat text and images. The best compression would be achieved if the whole text was extracted via OCR, but that is probably a lot more effort than you're willing to spend. Regards, Achim. -- +[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]+ Samples for the Waldorf Blofeld: http://Synth.Stromeko.net/Downloads.html#BlofeldSamplesExtra
Re: [O] [OT] Scanning for archiving
Thanks Achim! On Sat, Nov 5, 2011 at 2:34 PM, Achim Gratz strom...@nexgo.de wrote: Marcelo de Moraes Serpa celose...@gmail.com writes: I just bought a scanner and started to scan important documents as a backup, and archiving them with meaningful metadata in orgmode files. Then a question came to mind - what dpi to use? I'm not really savvy when it comes to scanning or printing, and I want like a dpi that allows me to reprint the document at an acceptable quality later if necessary, but that also doesn't take that much space (600dpi pdfs take around 5MB). Fax in fine mode has about 200dpi resolution. The raw scan should be in higher resolution (usually 2x-4x the target resolution depending on the document quality). The file to be archived then needs to be compressed (lossless compression is preferred, e.g. TIFF or PNG) and the bit depth reduced (black and white, usually). When making PDF files you need to make sure that the image data doesn't get re-coded (often into much inferior JPEG). For documents containing (color) images it is often preferrable to separately treat text and images. The best compression would be achieved if the whole text was extracted via OCR, but that is probably a lot more effort than you're willing to spend. Regards, Achim. -- +[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]+ Samples for the Waldorf Blofeld: http://Synth.Stromeko.net/Downloads.html#BlofeldSamplesExtra
Re: [O] [OT] Scanning for archiving
Hi Jan, I was in fact just looking at that article again a few minutes ago. I recalled that we had discussed that before briefly and that I saw it somewhere, and then I remembered about the discussion about your archiving system. Thanks again! Marcelo. On Sat, Nov 5, 2011 at 3:01 PM, Jan Böcker jan.boec...@jboecker.de wrote: On 11/05/2011 09:03 PM, Marcelo de Moraes Serpa wrote: Hi list, I just bought a scanner and started to scan important documents as a backup, and archiving them with meaningful metadata in orgmode files. Then a question came to mind - what dpi to use? I'm not really savvy when it comes to scanning or printing, and I want like a dpi that allows me to reprint the document at an acceptable quality later if necessary, but that also doesn't take that much space (600dpi pdfs take around 5MB). Hi Marcelo, I am using 300 dpi. Even the fine print on my cell phone contract is still comfortably readable at this resolution. I guess that about 150 dpi is sufficient for most documents, but I don't bother thinking about that on a case-by-case basis and just scan everything at 300 dpi. I do scan most documents in grayscale and only enable color when required. Said cell phone contract weighs in at 4.6 MiB for a 6-page grayscale PDF (about 770 KiB per page). Btw, my problem with big file sizes it not exactly disk space (which rapidly becomes cheaper with time) but the time it takes evince to display the document on my laptop :) If you are interested in the shell script I use to scan to PDF files, see http://www.jboecker.de/2010/04/14/general-reference-filing-with-org-mode.html#sec-5 Hope this helps, Jan
Re: [O] [OT] Scanning for archiving
On Sat, 5 Nov 2011 14:03:24 -0600, Marcelo de Moraes Serpa celose...@gmail.com wrote: Hi list, I just bought a scanner and started to scan important documents as a backup, and archiving them with meaningful metadata in orgmode files. Then a question came to mind - what dpi to use? I'm not really savvy when it comes to scanning or printing, and I want like a dpi that allows me to reprint the document at an acceptable quality later if necessary, but that also doesn't take that much space (600dpi pdfs take around 5MB). Any insights welcome, Thanks, Marcelo. Using PDF for scanned documents results in *huge* files with a seriously disappointing image quality. Consider storing your scans in DjVu format [1], which was developed specifically for this purpose. I scan all docs @ 600dpi, predominantly gray-scale (only in colour when it's *really* necessary) and store in DjVu format, all using gscan2pdf [2]. Even at that seemingly overkill resolution, single-page documents are generally (if they aren't too grainy) only a few 100 KiB in size. gscan2pdf also supports a number of OCR utils, but the UI for this is clumsy (aren't they all...), so you're better off using the CLI tools directly. Tesseract is recommended. I've used this approach to convert piles upon piles of old bank statements to Ledger format, with very little effort. NOTE: When attempting something like this, a fast scanner with a *reliable* automatic document feeder will help prevent premature hair loss ;) Peace -- Pieter [1] http://djvu.org/resources/whatisdjvu.php [2] http://gscan2pdf.sourceforge.net/
Re: [O] [OT] Scanning for archiving
I used to find that 8-bit 75dpi was legible and small. What ADF scanners are out there for Linux that have high quality reliable ADF, are fast, and work well with CLI tools? Is OCR at the point where it is feasible using CLI? Combining that with a new feature to have the Org agenda work with indexers (I participated in a discussion on that here a long while back) would be interesting. On 2011-11-05, Pieter Praet pie...@praet.org wrote: NOTE: When attempting something like this, a fast scanner with a *reliable* automatic document feeder will help prevent premature hair loss ;) ... [1] http://djvu.org/resources/whatisdjvu.php [2] http://gscan2pdf.sourceforge.net/
