26 Nov
2019
26 Nov
'19
6:52 p.m.
I am going through stuff in my office and found that I have some SCSI
device docs that aren't on bitsavers. As far as multi-page documents, it
seems as if my scanner (or its software) only does uncompressed TIFF. At
bitsaver's recommended 400 dpi, that means about 4M per page.
What should I do? Scan the docs in and find a tool to convert to
lossless compression. Scan the docs in and just submit the huge files?
Something else?
The docs that I have are copies, not originals. Does anyone here want
them after I scan them?
alan
26 Nov
26 Nov
7:05 p.m.
On 11/26/19 6:52 PM, Alan Perry via cctalk wrote:
I am going through stuff in my office and found that I have some SCSI
device docs that aren't on bitsavers. As far as multi-page documents, it
seems as if my scanner (or its software) only does uncompressed TIFF. At
bitsaver's recommended 400 dpi, that means about 4M per page.
What should I do? Scan the docs in and find a tool to convert to
lossless compression. Scan the docs in and just submit the huge files?
Something else?
The docs that I have are copies, not originals. Does anyone here want
them after I scan them?
Are these standards; e.g. official ANSI X3T10 docs?
--Chuck
7:23 p.m.
On 11/26/19 7:05 PM, Chuck Guzis via cctalk wrote:
On 11/26/19 6:52 PM, Alan Perry via cctalk wrote:
No, they are vendor docs on specific devices. CDC Wren IV. Exabyte 8200.
Adaptec AIC-6250 and AHA-1540A/1542A. Something else that I can't
recall. Most had related docs on bitsavers, but not these specific
documents.
alan
I am going through stuff in my office and found that I have some SCSI
device docs that aren't on bitsavers. As far as multi-page documents, it
seems as if my scanner (or its software) only does uncompressed TIFF. At
bitsaver's recommended 400 dpi, that means about 4M per page.
What should I do? Scan the docs in and find a tool to convert to
lossless compression. Scan the docs in and just submit the huge files?
Something else?
The docs that I have are copies, not originals. Does anyone here want
them after I scan them?
Are these standards; e.g. official ANSI X3T10 docs?
--Chuck
7:08 p.m.
you can ftp the uncompressed files to me and I'll take care of the conversions
On 11/26/19 6:52 PM, Alan Perry via cctalk wrote:
I am going through stuff in my office and found that I have some SCSI device docs that
aren't on bitsavers. As far as
multi-page documents, it seems as if my scanner (or its software) only does uncompressed
TIFF. At bitsaver's recommended
400 dpi, that means about 4M per page.
What should I do? Scan the docs in and find a tool to convert to lossless compression.
Scan the docs in and just submit
the huge files? Something else?
The docs that I have are copies, not originals. Does anyone here want them after I scan
them?
alan
7:10 p.m.
Al, is there a "standard" you would recommend us mere mortals to scan and
archive docs?
---8<---Corte aqui---8<---
http://www.tabajara-labs.blogspot.com
http://www.tabalabs.com.br
---8<---Corte aqui---8<---
Em qua., 27 de nov. de 2019 ?s 01:07, Al Kossow via cctalk <
cctalk at classiccmp.org> escreveu:
you can ftp the uncompressed files to me and I'll
take care of the
conversions
On 11/26/19 6:52 PM, Alan Perry via cctalk wrote:
I am going through stuff in my office and found that I have some SCSI
device docs
that aren't on bitsavers. As far as
multi-page documents, it seems as if my scanner
(or its software) only
does uncompressed TIFF. At bitsaver's recommended
400 dpi, that means about 4M per page.
What should I do? Scan the docs in and find a tool to convert to
lossless
compression. Scan the docs in and just submit
the huge files? Something else?
The docs that I have are copies, not originals. Does anyone here want
them after I
scan them?
alan
8:02 p.m.
On 11/26/19 7:10 PM, Alexandre Souza wrote:
Al, is there a "standard" you would
recommend us mere mortals to scan and archive docs?
I've moved to 600dpi bi-tonal tiffs for all new text work since that is the maximum
resolution my Panasonic KV-S3065 scanner supports. I use a flatbed at 300dpi jpeg for
pages with images
I'm not going to discuss the pros and cons of my work. This is what my workflow is and
is unlikely
to change any time soon.
7:51 p.m.
On 11/26/2019 8:52 PM, Alan Perry via cctalk wrote:
I am going through stuff in my office and found that I have some SCSI
device docs that aren't on bitsavers. As far as multi-page documents, it
seems as if my scanner (or its software) only does uncompressed TIFF. At
bitsaver's recommended 400 dpi, that means about 4M per page.
What should I do? Scan the docs in and find a tool to convert to
lossless compression. Scan the docs in and just submit the huge files?
Something else?
The docs that I have are copies, not originals. Does anyone here want
them after I scan them?
alan
This would be a function of the software, not the scanner.
When I corresponded with Al Kossow about format several years ago, he
indicated that CCITT Group 4 lossless compression was their standard.
I have been using a scanner (Ricoh IS300e) that needs a driver that
doesn't install under Windows 10, so now I use it from inside a Windows
7 VM. The software I have been using in Irfanview.
I expect it would not be tremendously difficult to find something that
would do the compression on a raw file.
JRJ
8:05 p.m.
As far as multi-page documents, it seems as if my
scanner (or its
software) only does uncompressed TIFF. At bitsaver's recommended 400
dpi, that means about 4M per page.
If you're on unix of some sort, the libtiff tools can convert these
uncompressed images to G4. The command you'd use would be tiffcp.
De
2 Dec
2 Dec
12:57 p.m.
On Tue, Nov 26, 2019 at 8:51 PM Jay Jaeger via cctalk <cctalk at classiccmp.org>
wrote:
When I corresponded with Al Kossow about format
several years ago, he
indicated that CCITT Group 4 lossless compression was their standard.
There are newer bilevel encodings that are somewhat more efficient than G4
(ITU-T T.6), such as JBIG (T.82) and JBIG2 (T.88), but they are not as
widely supported, and AFAIK JBIG2 is still patent encumbered. As a result,
G4 is still arguably the best bilevel encoding for general-purpose use. PDF
has natively supported G4 for ages, though it gained JBIG and JBIG2 support
in more recent versions.
Back in 2001, support for G4 encoding in open source software was really
awful; where it existed at all, it was horribly slow. There was no good
reason for G4 encoding to be slow, which was part of my motivation in
writing my own G4 encoder for tumble (an image-to-PDF utility). However, G4
support is generally much better now.
3 Dec
3 Dec
12:50 a.m.
On Mon, 2 Dec 2019, Eric Smith wrote:
There are newer bilevel encodings that are somewhat
more efficient than G4
(ITU-T T.6), such as JBIG (T.82) and JBIG2 (T.88), but they are not as
widely supported, and AFAIK JBIG2 is still patent encumbered. As a result,
*NEVER* use JBIG2! I hope you know about the Xerox JBIG2 bug (e.g. making
an 8 where there is a 6 in the original). Alone the idea of multiplying
parts from a scan in other areas is a no go. That's not archiving, that's
dumb. Therefore using compression algorithms like the one used in JBIG2
is discouraged or even forbidden e.g. for legal matters.
Christian
4 Dec
4 Dec
1:01 a.m.
Dear Mister Noname,
On Tue, 3 Dec 2019, it was written
That's _LOSSY_ JBIG2.
YOU DON"T HAVE TO USE LOSSY MODE!
Don't shout!!
And for the topic: you don't have to use JBIG2. Space isn't really an
issue today for scanned bilevel documents, so you can just stick with TIFF
G4 or PNG.
Christian
PS:
You should have a look at the netiquette that says "Only post with a
name" and "Be polite, don't shout".
3 Dec
3 Dec
9:59 a.m.
On 2019-12-02 4:57 p.m., Eric Smith via cctalk wrote:
On Tue, Nov 26, 2019 at 8:51 PM Jay Jaeger via cctalk
<cctalk at classiccmp.org>
wrote:
Is there any way to know what compression was used in a pdf file?
Do you know anything about a compression format JPEG2000?
Would TIFF G4 still be preferable to JPEG2000? It would seem I can
control the compression used by selecting the pdf compatibility level.
Paul.
When I corresponded with Al Kossow about format
several years ago, he
indicated that CCITT Group 4 lossless compression was their standard.
There are newer bilevel encodings that are somewhat more efficient than G4
(ITU-T T.6), such as JBIG (T.82) and JBIG2 (T.88), but they are not as
widely supported, and AFAIK JBIG2 is still patent encumbered. As a result,
G4 is still arguably the best bilevel encoding for general-purpose use. PDF
has natively supported G4 for ages, though it gained JBIG and JBIG2 support
in more recent versions.
Back in 2001, support for G4 encoding in open source software was really
awful; where it existed at all, it was horribly slow. There was no good
reason for G4 encoding to be slow, which was part of my motivation in
writing my own G4 encoder for tumble (an image-to-PDF utility). However, G4
support is generally much better now. 
10:13 a.m.
On Dec 3, 2019, at 12:59 PM, Paul Berger via cctalk
<cctalk at classiccmp.org> wrote:
...
Would TIFF G4 still be preferable to JPEG2000? It would seem I can control the
compression used by selecting the pdf compatibility level.
JPEG2000 apparently has a lossless mode (says Wikipedia). If so, it would be acceptable
as an alternative to other lossless compressions. If used in lossy mode, it's not
suitable for scanned documents, just as regular JPEG isn't.
paul
11:23 a.m.
On Tue, Dec 3, 2019 at 10:59 AM Paul Berger via cctalk <
cctalk at classiccmp.org> wrote:
Is there any way to know what compression was used in
a pdf file?
There's not necessarily only one. Every object in a PDF file can have its
own selection of compression algorithm.
I don't know of any user-friendly way to tell. Years ago I used some really
awful programs I hacked up to inspect PDF file contents. I'm not sure I
even can find them any more.
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