Large black point

[Guillaume Dargaud]

Hello all,
I'm in the process of scanning a family archive of (infamously lousy) Kodak
Discs. I scan the whole disc at once and I wrote a script to extract the
images (soon to be on my site). As such the scans need to have the black
point very high as most of the raw scan is black (there's only a narrow ring
of real images). I cut off the inner core with a blade to avoid white point
issues.

Is there a better way to scan the damn thing than to set the black point to
60% or such ? I always adjust it manually and then do a post-processing of
the individual images, but I'm trying to find the best workflow.
--
Guillaume Dargaud
http://www.gdargaud.net/

[CSM1]

Guillaume Dargaud <use_my_...@www.gdargaud.net> wrote in
news:4af72739$0$24645$426a...@news.free.fr:

The best workflow and least amount of image exposure errors may be if you
select each image on the disc, instead of trying to scan the whole disc
at once. Use the marquee to select just one image.

You would have much more control over the exposure, your window of good
image would not be so narrow. Use the scanner's auto exposure. If you cut
out all of the background (the white disc) auto exposure will work much
better.

It would be a slow way to scan the images, but I think you will pick
speed once you get the technique down.

Ignore the script a few times and see how the images turn out.

--
CSM1
http://www.carlmcmillan.com
--

[Barry Watzman]

In my experience, trying to scan multiple images give poor quality.
Crop down to one single image (image only), then you can set your
exposure parameters properly for that image and only that image.
Unfortunately, it's going to take a lot more time to scan your images
that way.

[Guillaume Dargaud]

I know you are both right about it being better to directly scan the image,
and that's how I proceed with other kinds of negatives (I never even use
batch scanning options), but those Kodak discs are just too annoying to
manipulate. I would need to rotate it each time by hand on a flatbed
surface: an impossible task without several attempts for each frame to get
the alignement at less than 1 degree.

BTW, for those interested here's the shell/ImageMagick script I use to split
the scan of the disc in its constituent images:
http://www.gdargaud.net/Photo/KodakDiskScan.html

[Nigel Feltham]

CSM1 wrote:

> The best workflow and least amount of image exposure errors may be if you
> select each image on the disc, instead of trying to scan the whole disc
> at once. Use the marquee to select just one image.
>
> You would have much more control over the exposure, your window of good
> image would not be so narrow. Use the scanner's auto exposure. If you cut
> out all of the background (the white disc) auto exposure will work much
> better.

I'm curious to know whether it's possible to select one image and use auto
exposure to calibrate the scanner and then use the same exposure to scan
all of the whole discs (assuming all the negatives have the same average
exposure - if not then you could divide them into light and dark images and
scan them in 2 batches calibrating exposure for each set).

[CSM1]

Nigel Feltham <nigel....@btinternet.com> wrote in
news:eZ6dnYuXvorraGDX...@brightview.co.uk:

It may be possible, but you can not do another Preview. You lose all
setting in preview.

I think you would be blind in positioning the disc.

I doubt that auto exposure would work, you would more likely have to do
Manual exposure.

Now if you can up with a mask that fit the disc image, you could then
position the disc over the cutout in the mask.

If you leave a calibration slot in your homemade mask, that might work.