plustek: [canon lide 20] poor color quality
Subject:
Re: [canon lide 20] poor color quality
From:
Alain Wenmaekers ####@####.####
Date:
28 Feb 2003 16:56:13 -0000
Message-Id: <200302281744.19064.alain.wenmaekers@skynet.be>
Op vrijdag 28 februari 2003 16:49, schreef Florent BERANGER:
> Hello,
>
> I've a Canon Lide 20 scanner (very small -> very practice ;) and the colour
> quality with plustek sane drivers is very poor, gray is saw as pink for
> exemple.
> What is the problem. Is there some solutions ?
There is a partial solution. (Or better say, there are 2 solutions).
I'm first going to quote some messages from to the mailing list (strange...
they don't appear in the web-archive...)
------------------------------------Mail1(by me)--------------------
settings that I found (caution, a better combination may exist):
option red_gain 1
option green_gain 37
option blue_gain 32
With these options, I'm able to see the difference between the colors
I have a testscan with some magazine pieces with colors in it:
-The original, with sane set to the default settings:
http://users.skynet.be/bluedigit/sanedefault.jpg
-The one with the changed settings (still ugly, but the different colors are
visible):
http://users.skynet.be/bluedigit/corrected.jpg
-The reference scan with "vuescan" (colors are much softer):
http://users.skynet.be/bluedigit/vuescan.jpg
---------------------------------Mail2(by Gerhard)----------------
> In your case, you might also get better results, when playing around with
> the y-offset of the white calibration strip. To find the correct value, you
> can adjust the startvalue 100 down to 0, then you'll see the calibration
> area Play around with this value to have only the white strip in the lower
> part of your picture, the new found value should replace the currently set
> 35...
> structure in line 645, file plustek-devs.c (Lide20)
> {{ 0, 100}, 35, -1, {2550, 3508}, {75, 75}, COLOR_GRAY16 },
-----------------------------------------------------------------------------
The value of 35 should be 25 (at least in my case). It gives a much better
picture, altough not optimal yet.
You could set this value and recompile sane, or just bypass calibration by
setting these values in plustek.conf:
---------------------------
option red_gain 8
option green_gain 41
option blue_gain 38
---------------------------
Best option is to use "vuescan" which gives even better quality than the
Windows driver. Unfortunately, vuescan is not free.
Grtz
Alain
