VueScan - bad handling of overexposed negs

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Bryan

I'd like to find out how I can get a decent image from an overexposed
color negative. Apparently, any of the color balance settings on the
Color tab will attempt to tone down the washed-out brightness, which
causes false coloring of the overall image. For instance, the
blue-white sky becomes a dingy, grainy yellow-brown color. I have
tried using the "None" and "Manual" settings without much luck. Has
anyone found a way to correct this and scan these negs so they look
presentable? I can send you an example of an image where this problem
appears if you'd like.

I wouldn't bother trying to make these images look better, except that
when I compare the VueScan results with the photo lab's prints, the
prints look WAY better, color-balance wise. I figured if a photo lab
can figure out how to expose these negatives, VueScan should be able
to duplicate that. For now, I'm scanning in the prints instead of the
negs, but I'd like to do the negs instead.

I am using a HP Photosmart S20 and have VueScan 7.6.75, in case that
makes a difference.

Thanks!
Bryan
 
Bryan said:
I'd like to find out how I can get a decent image from an overexposed
color negative. Apparently, any of the color balance settings on the
Color tab will attempt to tone down the washed-out brightness, which
causes false coloring of the overall image. For instance, the
blue-white sky becomes a dingy, grainy yellow-brown color. I have
tried using the "None" and "Manual" settings without much luck. Has
anyone found a way to correct this and scan these negs so they look
presentable?
Click to expand...

Have you tried the 'advanced workflow suggestions' in the user manual?
Your problem seems familiar to me - not only with overexposed negs but
also with correctly exposed negs that contain lots of highlights. The
'advanced workflow' mostly seems to make the problem disappear.
 
SNIP
Have you tried the 'advanced workflow suggestions' in the user manual?
Click to expand...

Exactly what I would have suggested, but you beat me to it ;-)

Those 'difficult' color negatives require a bit more attention than a
correct exposure, but there is of course a limit to what can be done after
severe overexposure. However, given the fact that the OP's prints appear to
look sort of acceptable, it is likely that VueScan can do at least a similar
job.

Especially the "Advanced Workflow" and the Right-Mouse-Button click on a
neutral area (non-saturated white works best for negatives) should get one
close to an acceptable rendering of the original scene. If the overexposure
is too extreme, I'd suggest to concentrate on shadow to mid-tone accuracy,
and tweak the highlights afterwards (curves or selective color in Photoshop
if available).

Bart
 
Thank you, that did help quite a bit. The scans are at least
presentable now, although still not quite as good as the photo lab
prints. There are still some darkish streaks in the direction of the
scan in the highlights (mostly in the sky), but it's way better than
it was before locking film base color and exposure. I had thought
that selecting the correct film type would have done this, but I guess
not.

I notice that it scans more slowly when these "lock" boxes are
checked, even though the scan dpi has not changed. I don't know why,
and I think I won't question it as long as it works. ;-)

Thanks again,
Bryan
 
And by the way, I just wanted to submit my disdain for the cheap
throw-away cameras. Yes, I am trying to scan negatives from one of
these and the quality is terrible to begin with. They load them with
800 film (upside down and backwards, no less!), and then have a cheap
plastic lens and a fixed shutter speed. What do you think will happen
when you take pictures with it in bright sunlight?? :-)

Bryan
 
Bryan said:
I notice that it scans more slowly when these "lock" boxes are
checked, even though the scan dpi has not changed. I don't know why,
and I think I won't question it as long as it works. ;-)
Click to expand...

The scan time is linearly related to "Input|RGB exposure". The
longer the CCD is exposed, the longer the scan takes.

Regards,
Ed Hamrick
 
Ah, that explains it Ed, thank you. The RGB Exposure is set to 1.981,
so I assume that means it's scanning slower than 1.000 (if that's the
normal setting).

Bryan
 
Any idea what might be causing the darker streaks in the sky on
overexposed negatives? Could it be CCD noise or something? Or is
VueScan trying too hard to balance the color when it should just be
letting it go white and low-contrast?

Bryan
 
Bryan said:
Any idea what might be causing the darker streaks in the sky on
overexposed negatives?
Click to expand...

It's related to hardware calibration/initialization (uniform matching the
sensitivity of the CCD elements along the array and between arrays if
appplicable). The remaining differences are most visible in low signal (=
dense) film areas. Try re-calibration from the "Scanner" menu.

Bart
 
The HP S20 scanner has a calibration card, but only in "Photo" mode,
not for negatives/slides. Not sure if one calibration works for all
settings, but even when I recalibrate, turn it off/on, reset the
firmware -- I still get dark streaks in the highlights of underexposed
negs.

But... I must say that Locking Exposure and Film Base Color certainly
makes a world of difference for these rolls shot with a throw-away
camera! It doesn't make much difference for the same film shot with
my Canon T70 though.

Bryan
 
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