Setting Black and White points in Vuescan,,can I set to clip less?????
Neil Lukas
Anyone know how I can manually set black and white points?
I know that when setting Color Balance to Neutral, White Balance, Auto
Levels, I can adjust White and Black points to clip more, but I want to
clip LESS! The setting for "None" doesn't have any White balance
adjustment.
I know I can scan with "None " set for color balance, and adjust in
Photoshop, but That is less than ideal. Am I missing something?
For example, scanning a 4x5 Tranny of a vase of flowers, where there is
no pure white in the image, Vuescan will clip the brightest 1% of
pixels, giving me white where it isn't.
Using Powerlook III.
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Pasi Savolainen
> I just bought Vuescan, and think it's great, with one problem...
> Anyone know how I can manually set black and white points?
> I know that when setting Color Balance to Neutral, White Balance, Auto
> Levels, I can adjust White and Black points to clip more, but I want to
> clip LESS! The setting for "None" doesn't have any White balance
> adjustment.
> I know I can scan with "None " set for color balance, and adjust in
> Photoshop, but That is less than ideal. Am I missing something?
> For example, scanning a 4x5 Tranny of a vase of flowers, where there is
> no pure white in the image, Vuescan will clip the brightest 1% of
> pixels, giving me white where it isn't.
> Using Powerlook III.
Umm. I usually have it at 'white balance' and black & white point
written to 0.01.
You can write in those boxes too, you know.
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Jon Bell
Neil Lukas <acmesilver....@web2news.net> wrote:
>For example, scanning a 4x5 Tranny of a vase of flowers, where there is
>no pure white in the image, Vuescan will clip the brightest 1% of
>pixels, giving me white where it isn't.
Just type something smaller than 1 into the "white point" box. I often
use 0.5 or 0.2 or even smaller. Same holds for the "black point" and
"brightness" boxes. I never use those sliders.
--
Jon Bell <jtbe...@presby.edu> Presbyterian College
Dept. of Physics and Computer Science Clinton, South Carolina USA
Neil Lukas
> >
> Umm. I usually have it at 'white balance' and black & white point
> written to 0.01.
> You can write in those boxes too, you know.
Thanks Pasi, but even with the white point set at 0.0 , it clips the
brightest 1% of pixels, turning them them white. I tried setting the
white balance to a negative number, but all it did was decrease the
overall contrast of the image..I still got white pixels where there were
none in the image.
Neil
Erik Krause
you wrote...
> Thanks Pasi, but even with the white point set at 0.0 , it clips the
> brightest 1% of pixels, turning them them white. I tried setting the
> white balance to a negative number, but all it did was decrease the
> overall contrast of the image..I still got white pixels where there were
> none in the image.
If you lock image color you can set the white point to an absolute
value. You will have to lock exposure first and do a new preview until
the lock image color checkbox appears.
Other possibility is that the CCD is overexposed. Try reducing exposure
manually. If you have a newer version you can adjust Exposure clipping
too.
--
Erik Krause
Digital contrast problems: http://www.erik-krause.de/contrast
Leonard Evens
> I just bought Vuescan, and think it's great, with one problem...
> Anyone know how I can manually set black and white points?
> I know that when setting Color Balance to Neutral, White Balance, Auto
> Levels, I can adjust White and Black points to clip more, but I want to
> clip LESS! The setting for "None" doesn't have any White balance
> adjustment.
> I know I can scan with "None " set for color balance, and adjust in
> Photoshop, but That is less than ideal. Am I missing something?
> For example, scanning a 4x5 Tranny of a vase of flowers, where there is
> no pure white in the image, Vuescan will clip the brightest 1% of
> pixels, giving me white where it isn't.
> Using Powerlook III.
Perhaps I misunderstand, but it was my impression that with the white
and black points set to zero, you aren't going to clip anything. That
certainly appears to be my experience. I certainly can arrange to have
no value above about 240 if I want. I scan mainly negative film, bw or
color, but I've also scanned some slide film. It may be that your
transparencies are beyond the dynamic range the scanner can handle.
--
Leonard Evens l...@math.northwestern.edu 847-491-5537
Dept. of Mathematics, Northwestern Univ., Evanston, IL 60208
ThomasH
>
> In article <3284...@web2news.com>,
> Neil Lukas <acmesilver....@web2news.net> wrote:
> >For example, scanning a 4x5 Tranny of a vase of flowers, where there is
> >no pure white in the image, Vuescan will clip the brightest 1% of
> >pixels, giving me white where it isn't.
>
> Just type something smaller than 1 into the "white point" box. I often
> use 0.5 or 0.2 or even smaller. Same holds for the "black point" and
Yes, do so. 1% white point will definitely spoil your detail in
highlights. Observe some cloudy sky and compare a few previews
while lowering white point. Setting white point to any value not
equal 0.0 improves the contrast of the scan in Vuescan, but I
usually live with as few as 0.1 or even 0.02%. I my use I rather
see the need for the black point, in which case use Vuescan
7.6.38 or a later version.
Thomas
Neil Lukas
> Thanks guys, I think I've got it. The transpaarencies do have an
extreme dynamic range, but I found that changing the exposure clipping
setting to a very low value helped a lot.
Thanks again,
Neil
www.acmesilver.com
