[sane-devel] artec e+pro- vertical lines- some samples

[Philip Aston]

All are prints of as near to pure red blue green as I could find using
drawing tools on MSword, printer is a Tallygericom colour laser, I see the
fabric effect as horizontal/ vertical "tartan". To hopefully exclude this I
uploaded "blue2.pnm" which is a slightly darker than mid blue from a
flysheet of a book. Regards-Philip

-----Original Message-----
From: m. allan noah [mailto:kitno455 at gmail.com]
Sent: 13 January 2008 21:10
To: kilgota at banach.math.auburn.edu
Cc: Philip Aston; sane-devel at lists.alioth.debian.org
Subject: Re: [sane-devel] artec e+pro- vertical lines- some samples


On 1/12/08, kilgota at banach.math.auburn.edu wrote:
> What I see in these images is, something like what I suspected could be a
> possibility, or it could be something else.

well, that about covers all the possibilites :)

> It is difficult to tell
> without the actual raw data. I assume (without actually knowing) that
> there is a SANE option to capture the raw data and dump to a file, with no
> processing at all.

You very well might BE looking at the raw data. Since scanners use a
1-D instead of a 2-D array, they dont have any need to conserve
internal storage space, and their cpu's are generally quite slow, they
dont typically use much compression. Some machines do have jpeg
compression, but that requires a bit more horsepower. so- all in all,
i think you are pretty far off-base.

As a consequence of their low cost/power, many machines cannot
self-calibrate. That is my guess for the culprit here.

Philip- what are the three 'colored' scans of? I ask because the blue
has some sort of diagonal pattern the others dont have, almost like a
denim material.

allan
--
"The truth is an offense, but not a sin"