Some time ago you had replied to my email asking
about Canoscan FB1200S support (this seems to be the only SCSI flatbed
scanner Canon has on the market now, see below for a description).
I finally did get one (after trying and returning a Microtek X6EL)
and am glad to report that it works well enough for my purposes, even
with the old Canon driver which came with sane-1.0.1. A brief
summary of my observations is given below, but first I would like to ask a
question: has anyone gone through the procedure of colour calibration
using a colour target, like the Kodak IT-8, using sane and open-source
software? I intend to do so at some point, so any information would be
very useful.
Backend and xsane related things:
- Only 8-bit scanning works, 12-bit scanning does not
- Scanning upto 600 dpi works
- Scanning at 1200dpi does not work. It produces garbled images.
Moreover it hangs the scanner, which has to be power cycled.
I suspect this might be happening because 1200dpi scanning is
done in 2 600dpi passes, with an offset.
- the colours are coming out quite well. my monitor needs a gamma
enhancement of about 1.4-1.6 to improve the "brightness" (i do this in the
display program).
- xsane-0.41 comes up with the invert negative box checked. It also
has boxes for autofocus and autoexposure, which don't seem to make much
difference.
- if i start xsane after saving my device preferences in a previous
session, it segmentation faults immediately (see below for my computer setup).
it seems that the crash is directly caused by the "negative" entry in the
device preferences; getting rid of it fixes the problem.
About the Canoscan FB1200S:
- It seems to be the only SCSI flatbed scanner Canon is selling now. The
others are the 620U and 620P, with USB and parallel connections respectively. I
could not find the Canoscan 600 for sale anywhere.
- It has two types of SCSI connections: a DB25 old-style SCSI
connection, and a SCSI-2 type of connection, which I believe is 50 pins; both
female receptacles.
- It comes with an Adaptec SCSI card, which I am not using.
- It does not seem to have a power switch. You have to pull out
the adapter cord.
- I couldn't find a paper manual for the scanner in the box.
- The scan bed seems to be made of plastic rather than glass.
- The bed size is A4.
- It is supposed to do 1200x1200 dpi optical resolution.
- the picture and especially colour quality is much superior to
the Microtek X6EL, which I had previously and returned.
- scanning speed is about 35 seconds for an 8.5x11 inch page at
300dpi and 8-bit RGB colour. it paused several times during this scan. for
3x5 inch photographs at the same resolution, it does not pause.
- i checked the scan data consistency by making several scans of
the same picture, and comparing them pixel by pixel using:
pnmarith -diff test1-{1,2}.ppm | ppmtopgm | pgmhist
the histogram dropped to 0.01% at a gray-level difference of around 40-48,
and this was consistent over different pairs chosen from 6 scans; the
maximum gray-level difference was about 60. I could not tell the difference
between the scans visually. (interestingly, the Microtek X6EL behaves quite
differently: the 2rd and 3rd scans are always the most consistent, with a
0.01% histogram point of 6 or 7 and a max difference of 9; but the colours
are bad, and (experimental) backend colour correction using the microtek2
backend is very erratic at this point).
- It costs around $260 by mail order (eg www.buy.com); I walked in and
bought it from J&R Computer World in Manhattan for $299. I actually tried their
display model with sane from my laptop before buying it. The impression I got
was that it was not being pushed by the sales staff, who seemed surprised I
wanted to buy it. They were especially impressed it worked "out of the box"
with linux, and said it didn't work well with Windows98. I haven't tried it with
Windows yet.
My computer setup:
- IBM Thinkpad 570 laptop (366MHz Celeron, 192 MB RAM).
- kernel 2.2.12 (Slackware 4.0), sane-1.0.1, xsane-0.41
- New Media Bus Toaster PCMCIA SCSI-II adapter (50pin
SCSI-II connector), also the Zipcard PCMCIA
SCSI adapter (with a DB25 connector). Both work with the
scanner. I am using module-based SCSI support with 3c589_cs.
- gimp 1.0.4, and the imagemagick and netpbm tools
Best wishes,
Jaijeet
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Jaijeet Roychowdhury Communication Sciences Research
phone: 908-582-3492 Bell Laboratories
fax: 908-582-4092 Room 2b-216, 600 Mountain Avenue
email: jaijeet@research.bell-labs.com Murray Hill, NJ 07974, USA
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