Re: filmscanners: Colormatch RGB

["shAf" <michael@shaffer.net>]

Rob writes ...

> While scanning various colour negatives using Vuescan, I became
frustrated
> by the lack of colour saturation when using Adobe RGB and (believe
it or
> not) sRGB as the colour space.  I found that if I scan using
Colormatch
> RGB then open the file in Photoshop *without* doing a profile
conversion
> (and yes, I know this is "against the rules"), the colours end up
much closer
> to the correct saturation and requires a lot less mucking around.
My only
> frustration with this is that reds seem to behave strangely.  ...
>
> Other people have said they use Colormatch RGB as a matter of
course - but
> I don't think I would, due to this behaviour.  ...
> ...
> Anyone like to make any comments?

    How can we comment when you even admit you load ColormatchRGB data
"against the rules"??  BTW ... you say you bring your VS scan into PS
w/o conversion, but you don't say which RGB space you bring it into
... AdobeRGB?   The maverick behaviour and unpredictability of reds is
most likely due to ColormatchRGB being edited in some other color
space, ans we cannot comment 'less we know which.  But I'll probably
still reccommend you "play by the rules".

    I have also noticed what you describe (when playing by the rules).
When you "play by the riles", one thing you can depend on VS for is
not to deliver an oversaturated image, and sometimes (or commonly)
undersaturated.  I believe this is a good thing ... primarily because
you can depend on all your RGB data being editable.  That is, I
imagine why your saturated reds are not editable is because their
values are heavily weighted towards the bright end of the histogram
... possibly even clipped at 255 ... or your working color space has
these red values spread over too few editable values.  If they were
undersaturated, you could at least depend their values being editable.

    I appreciate VS especially for the editability of the RGB data it
captures.  However, and I admit, the subsequent image is usually not
what I subjectively wanted ... but I always scan highbits into
Photoshop and create what I subjectively want there.  But, and to get
back to your question, I "play by the rules", and I believe if you did
too, you'd at least be able to edit your reds.

shAf  :o)