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RE: re[2]: filmscanners: re: brown yellow down side of Acer Neg scans

Hi Alan,

I think you suffer from the same problem as me. My scanner was just returned
from Acer only to show the old problems. I received two new holders, but no
better scans. All the things you did and Eds suggestions I had done before I
sent in the scanner.  :-( 
But there again is a bright light: I've got Acer mailing with me again: they
asked for more scans to see if they can come up with another solution. So I
gave them a few (did most of them last night). Who knows what good can come
out of this, even if it does not help me personally. Thanks Acer! (a few of
them are bcc-d again, among them the engineer working on my case)

Here are the scans I made with the returned scanner:
(links because the files are big, app. 1600x1200 pixels!)

http://www.bigfoot.com/~jerfi/testscannerfix/Burgers_2_17.jpg (+/- 700k,
Vuescan). Notice that there is some kind of smog in the sky along the long
sides of the frame, as if we had vertical layers of smog on this beautiful
day. Read-outs confirm that the sky at these brown yellowish spots has
larger R and G values, where B stays mostly the same compared to the middle
of the frame. If you want the effect to be exaggerated lower the gamma value
of the blue channel (don't know why this works though). Btw. I blurred the
sky which I didn't do with the other scans.

Miraphoto 2.0 scans
http://www.bigfoot.com/~jerfi/testscannerfix/Miraphoto_origin_2.jpg (97%
quality jpg, +/- 700k). This scan is made with as much as possible neutral
settings of Miraphoto. Watch the snow: commercial prints do not show
differences in color of snow between border and middle of the frame.

A smaller version with some color - balancing.
http://www.bigfoot.com/~jerfi/testscannerfix/Miraphoto_balance_3.jpg (90%
quality jpg, +/- 300k).

Vuescan versions of the same frame (Sorry Ed, I changed the black and white
points such that the scan does not look so good, even worse than Miraphoto,
but I did it to clip as few as possible data):
http://www.bigfoot.com/~jerfi/testscannerfix/Vuescan_origin_2.jpg (97%
quality jpg, +/- 700k).  
http://www.bigfoot.com/~jerfi/testscannerfix/Vuescan_balance_3.jpg (90%
quality jpg, +/- 300k).

Here is the scan I sent to this newsgroup and to Mr. Honda Lo from Acer
Taiwan before I sent the scanner into service. Scan made by a Miraphoto
color raw scan, followed by a vuescan scan from disk file.
good luck to your problem with the scanner Alan, 
I wouldn't mind seeing a few examples of scans with that problem from you,
so we can see if it is the same problem we are talking about.

Kind regards,

Jerry Oostrom

BTW. I think such symptoms could be solved by either replacing the CCD or
adding black point calibration to the unit. This we had already discussed
some time ago in this list. Of course electric interference and other
problem sources cannot be ruled out, but I don't know how to investigate
that possibility and what solutions to search for in that case.

Question to the list: if the hardware does not allow black point
calibration, is there any way I can do it myself? Perhaps using masks etc?

> -----Original Message-----
> From: Alan Womack [SMTP:arwbackup@worldnet.att.net]
> Sent: Thursday, May 31, 2001 3:51 PM
> To:   Majordomo leben.com
> Subject:      re[2]: filmscanners: re: brown yellow down side of Acer Neg
> scans
> I closely examined the calibration port on the negative film area, there
> is nothing in there to interfer.  I also did a little vaucumning of the
> entry door on the scanwit and a squirt of compressed air to remove dust
> etc that may have found refuge in the scanner to no avail.
> The yellow/brown on the side of the negative continues.  I will have to
> try a kodak neg next as this was with Fuji 100.
> Alan
>  >>  > I just checked a frame with the problem in Miraphoto 2.0 and it
> exhibits
>  >>  
>  >>  the 
>  >>  > same yellow/brown cast down the right hand side on this sky
> negative.  A
>  >>  
>  >>  > difference of up to 12 points blue.
>  >>  Double-check that you don't have anything blocking the light path in
>  >>  the film holder in the calibration area.

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