Vuescan- manual versus neutral?

[Roger]

I've been using Vuescan for a while now and thought I had a handle on
how it worked, but I'm wondering if someon can clarify the difference
between the "manual" setting for color balance set to the defaults
versus "neutral" color balance.

Having profiled my dedicated film scanner (Canon FS4000US) with an IT8
target I find that I get results that are closer to the slide by
setting black and white point clipping to 0% while using the manual
color balance setting. I have not changed the neutral RGB values or
the RGB brightness values and thought that the manual setting at its
defaults would be identical to "neutral." Apparently that isn't the
case as scanning in neutral gives a pale blue cast to the Provia E-6
slides I tested and seems to dull the reds a bit. Manual looks more
like the slide.

While this works for me I'm wondering if anyone can explain *why* this
is. The other issue is that the shadow region of the slides appears
darker on the monitor than the original slide, and I've been just
manually correcting that with curves in Photoshop (very annoying and
not always possible to do well).

Roger

 

[Erik Krause]

Having profiled my dedicated film scanner (Canon FS4000US) with an IT8
target I find that I get results that are closer to the slide by
setting black and white point clipping to 0% while using the manual
color balance setting. I have not changed the neutral RGB values or
the RGB brightness values and thought that the manual setting at its
defaults would be identical to "neutral." Apparently that isn't the
case as scanning in neutral gives a pale blue cast to the Provia E-6
slides I tested and seems to dull the reds a bit. Manual looks more
like the slide.

While this works for me I'm wondering if anyone can explain *why* this
is.

Select either of these settings. Go to input tab and lock image color.
Then go back to color tab and see where the absolute white point value
is for. Unlock image color and try this for the other setting, too.

Could well be Manual uses some previous value stored in vuescan.ini. To
be sure, rename vuescan.ini and try again.