[filmscanners] RE: Thumbnails looking flat

["Alex Zabrovsky" <alexz@zoran.co.il>]

Well, I did simple comparisons saving the same file in four versions:
Adobe 98 RGB with embedded ICC profile;
same without profile embedding;
sRGB (converted from Adobe in PS7) with profile embedded;
sRGB without embedding the profile

Opening them in Win XP image viewer revealed the best appearance of all
achieved by sRGB with profile embedded (though the visual difference between
the latter two isn't very significant).
Perhaps XP unlike the previous OSs is able finally to manage ICC profiles
while rendering the image by OS ? (Frankly, I doubt though).

Yesterday I examined the images I talked about and after some trial tweaking
in PS7 (following reading and learning image processing tools offered by
this software though PS7 book I just purchased) I begun to realize that
there might be additional variable in the equation which in fact contributed
mostly to the lack of contrast and saturation in my images.
The pictures seem to have noticeable coolness (not so obvious bluish cast)
like one caused by haze and cool lens rendition.
Once I was able to tweak the blue channel a bit with Curves tool this bluish
curtain was removed revealing good contrast and contributing to saturation.
I also recalled that just prior to that shooting taking my camera out of the
bag, the UV filter has became fogged considerably due to heavy local
humidity so I had to remove it for the whole session. The lens itself is
known for excessive coolness color rendition so I think that was the reason
for my confusion. A while ago I decided to switch the UV filter on this lens
for Skylight which would supposedly compensate much better for that, but was
lazy to do it contemplating about dumping the les itself for another one.

Anyway, it's apparently possible to correct the images in PS for that so I
hope soon to enjoy their real appearance.
Thanks for your advices.

Regards,
Alex Z

-----Original Message-----
From: filmscanners_owner@halftone.co.uk
[mailto:filmscanners_owner@halftone.co.uk]On Behalf Of Paul D. DeRocco
Sent: Friday, September 20, 2002 1:11 AM
To: alexz@zoran.co.il
Subject: [filmscanners] RE: Thumbnails looking flat


As I said, web browsers (at least under Windows--I don't know about the Mac)
don't do any color management. They just give the RGB data to the video
display. This means that the data are interpreted as though they were in a
color space defined by the monitor profile. My monitor profile is very close
to sRGB, and indeed I understand that sRGB was designed to be comparable to
a typical monitor. My LCD has an even smaller gamut.

I doubt the original poster's dullness problem comes from the conversion
from Adobe RGB to sRGB. If you're looking at the images on a typical
monitor, then those extra colors that Adobe RGB contains aren't visible
anyway. If an image really contains those colors, then the ICM engine may
indeed be desaturating all colors, rather than clipping them (that's what
"perceptual" rendering intent means), but not that many images really have
such saturated colors in my experience.

--

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@ix.netcom.com

> From: Joe
>
> It's my understanding the sRGB is the narrowest RGB gamut available in
> PS's default color space options. I know that Adobe RGB is wider, and so
> it is clipping some colors in moving from one to the other.
>
> Perhaps this is causing the dullness. Is the concensus RGB color space
> for  web display of jpegs sRGB? If that's the case, I can't see any real
> reason why, aside from overcautiousness.

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