Bob Armstrong schrieb:
> The 0.04 setting gives about the right level of maximum RGB. Another
> negative produced a similar pattern of results but required a white
> point of 0.15 for optimum results.
Hi, Bob,
this is one of the reasons why I am still reluctant to using Vuescan for
my LS-30. You actually *can* get the histogram stretched out perfectly
but each file will most likely require several attempts to find the
white point optimum. The Nikon Scan prescan histogram will allow to get
this precisely in the first round.
> I have not done any other tests. It seems that one can get 40% more
> colours from VS by stretching the image to fit the histogram
> by adjusting the white point.
Exactly. Leaving the white and black point at 0.000 in VS will most
likely give away shadows and/or highlights, the more of them the less
contrast the image has. 20 to 40% would be an average number with my
negatives.
> Even more colours are produced where the white point is set to clip
> the highlights. This is all very well but what the hell does it mean?
I assume clipping the highlights would cause some more detail to appear
in the midtones. OTOH, missing detail is extremely sharply visible in
the highlights ("blown out"). I'd rather give away that extra number of
colors than sink my highlights into white.
> Should I be setting the white point to just below clipping before scanning?
If I'd have to use Vuescan, I'd go for a scan that ends just below 255
for each channel in the highlights and just up 0 as to the shadows. If
even one channel sinks into 255, you'll see a noticeable difference to
an image which has its R, G and B histogram end below 255.
Best regards -
Ralf
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