Computer Graphics with Photoshop - RAW and colour space

Author

RAW and colour space

Bobby Edwards

2005-08-17, 11:14 pm

I am opening and adjusting RAW files in Capture One, which I like

When I process these to tiffs to open in PS, there is a subtle but
noticeable change in colour between what I have sent from Capture One to
what opens in PS.

I open in Adobe RGB on PS and assume that this is the reason. Is there any
way around it, other than adjusting in PS or overcompensating a bit in
Capture One which seems to defeat the object? My monitor is calibrated and
I've used Natural Colour which came with it (it's a Samsung LCD, to do this,
rather than Adobe Gamma, as I finf Narural Colour slightly easier to use.

Bobby E

PS When I openthe same file in Paint Shop Pro the image is incredibly dark
and nothing like the original.?????

Bill Hilton

2005-08-18, 4:14 am

>Bobby Edwards writes ...
>
>I am opening and adjusting RAW files in Capture One, which I like

Same here ...

>there is a subtle but noticeable change in colour between what
>I have sent from Capture One to what opens in PS.
>I open in Adobe RGB on PS and assume that this is the reason.
>Is there any way around it

Are you converting the files to AdobeRGB space from Capture One? If so
then you shouldn't see *too* much difference. You can set the color
space by clicking Workflow - Show Color Management Settings and picking
Adobe RGB from the 'output destination' drop down. Keep in mind what
you see on the screen in Capture One is just a preview, it seems
reasonable the converted file might look a bit different. I don't
really see a noticeable difference myself but I wasn't looking for it
either ... next time I fire it up I'll look more closely :)

>PS When I openthe same file in Paint Shop Pro the image is incredibly
>dark and nothing like the original.?????

The color management in PSP 9 and earlier is pretty bad. The only
working space profile it recognizes is sRGB and if you open a file with
a different profile it does not convert (the right way to do it),
instead it just ignores the profile, meaning the colors will be screwed
up.

Bill

Bill Hilton

2005-08-18, 4:14 am

> I don't really see a noticeable difference myself (between the Capture
>One preview and the tiff opened in Photoshop) but I wasn't looking for
>it either ... next time I fire it up I'll look more closely

OK, curiosity got the better of me so I opened a RAW file in CO
(Capture One), converted it at default settings and then opened the
tiff in Photoshop and compared side-by-side on the screen. I can see a
slight difference but not much ... here's a screen dump (fairly big,
sorry) of the two images side by side, with four points marked in the
Info palette (1,3 in the CO preview on the left, 2,4 in the CS tiff on
the right) ... as you can see these numbers are pretty close for the
light area above the beak and the green.
http://members.aol.com/bhilton665/owls_c1_cs.jpg

In the jpeg I created it looks to me that the CO image is now a bit
redder so I went back to the original screen dump and measured a
feather at 125/93/54 (RGB) in AdobeRGB space. When converted to sRGB
(prior to converting to a jpeg for the web) this changes to 137/93/48,
so things get redder with the profile conversion. The difference
between the two birds wasn't as noticeable when in AdobeRGB space so
some of what you see in this jpeg was caused by the profile conversion.

Anyway, this is the difference I see between the CO preview and the
final tiff in Photoshop. If you're seeing something more drastic I'd
look at the CO settings but if this is similar to what you're seeing
(minus the differences caused by the red shift) then I guess that's
about what to expect. Maybe I'll do the same test in Photoshop (ie,
see how close the preview in the CS RAW converter is to the final tiff)
....

Bill

Bart van der Wolf

2005-08-18, 7:14 am

"Bill Hilton" <bhilton665@aol.com> wrote in message
news:1124339124.175755.84420@g14g2000cwa.googlegroups.com...
SNIP
> OK, curiosity got the better of me so I opened a RAW file
> in CO (Capture One), converted it at default settings and
> then opened the tiff in Photoshop and compared side-by-side
> on the screen. I can see a slight difference but not much ...
> here's a screen dump (fairly big, sorry) of the two images
> side by side, with four points marked in the Info palette (1,3
> in the CO preview on the left, 2,4 in the CS tiff on the right) ...
> as you can see these numbers are pretty close for the light
> area above the beak and the green.
> http://members.aol.com/bhilton665/owls_c1_cs.jpg

It seems, to me anyway, that the Photoshop screen image on the right
is being sampled at a slightly different position (a bit more to the
right) for the 1 vs 2 sample. That might explain the slight read-out
difference.

Bart