Computer Graphics with Photoshop - What does an ICC profile change?

Author

What does an ICC profile change?

Philip Procter

2005-05-05, 11:14 pm

When I change to a different profile (say from RGB 1998 to the profile
that came with my Canon) what is changing: the screen image, the
printer image or both?

I've tried taking a portrait and swapping profiles but I don't see any
difference in the image on monitor or on paper.

Philip

Craig Flory

2005-05-06, 7:15 pm

Each color lab uses an icc profile. My main pro lab uses SRGB. Another uses
Adobe 1998. Also, each ink jet printer has a profile. You should know what
profile your printer uses as well as any outside labs you use. I also
recommend running the Adobe Gamma. If you use a pro lab get a kit from them
for setting up your monitor to match their output.

Craig Flory

Alan Justice

2005-05-06, 7:15 pm

Each device has its own color language. The profile simply tells the input
device what language it is speaking so it can compensate. That way the
monitor displays it the way the scanner says it should, and the printer
prints to look like it does on the screen.

--
- Alan Justice

"Philip Procter" <philip.procter@loctite.com> wrote in message
news:67jl715r6u69t7gnbk5vqmi2p6iqi77jaa@4ax.com...
> When I change to a different profile (say from RGB 1998 to the profile
> that came with my Canon) what is changing: the screen image, the
> printer image or both?
>
> I've tried taking a portrait and swapping profiles but I don't see any
> difference in the image on monitor or on paper.
>
> Philip

Bill Hilton

2005-05-06, 7:15 pm

>When I change to a different profile (say from RGB 1998 to the profile

>that came with my Canon) what is changing: the screen image, the
>printer image or both?

The RGB numbers are changed ... in a perfect world, they are changed so
that what you see on the screen will look as close as possible to what
you see on the print.

>I've tried taking a portrait and swapping profiles but I don't see any

>difference in the image on monitor or on paper.

Enable soft proofing and you should see the differences between what
can be displayed on the screen and the reduced brightness of the print.
You especially see this if you enable 'simulate:paper white'.

Also, if you have an image with bright reds and oranges (for example)
or just a test file with these colors you can see the differences
between say AdobeRGB and sRGB in the more saturated colors ... just do
image > mode > convert to profile and then ctrl-z back and forth to see
this.

>When I change to a different profile (say from RGB 1998 to the profile

>that came with my Canon) ...

I assume "RGB 1998" is AdobeRGB, right? You should distinguish between
different classes of profiles ... AdobeRGB and sRGB (and others) are
"working space" profiles, abstract profiles that are grey-balanced and
defined for a particular gamut width. So you would edit your files in
those. When you look at the file on the screen it's being adjusted by
your monitor ICC profile on the fly so the colors represented by the
RGB values match your specific monitor. This monitor profile is a
"device specific" profile (as opposed to the non-device specific
working space profiles, which don't match a specific device). When you
print with an ICC profile you're translating the RGB values again, this
time to a device-specific printer profile that hopefully translates the
numbers so the print looks as close to the monitor as possible. You
can actually read off these translated numbers if you have a file open
and apply a soft proof (view > proof setup > custom) and open the Info
palette and right-click on the second eyedropper and change it to
'proof color'.

If this is unclear here's a good link explaining the basics of
translating the RGB triplets to different values for different devices
using the ICC profiles ...
http://www.creativepro.com/story/feature/13605.html

Bill

careful@att.net

2005-05-07, 7:14 pm

Bill Hilton wrote:
>
>
>
> The RGB numbers are changed ... in a perfect world, they are changed so
> that what you see on the screen will look as close as possible to what
> you see on the print.
>
>
>
> Enable soft proofing and you should see the differences between what
> can be displayed on the screen and the reduced brightness of the print.
> You especially see this if you enable 'simulate:paper white'.
>
> Also, if you have an image with bright reds and oranges (for example)
> or just a test file with these colors you can see the differences
> between say AdobeRGB and sRGB in the more saturated colors ... just do
> image > mode > convert to profile and then ctrl-z back and forth to see
> this.
>
>
>
> I assume "RGB 1998" is AdobeRGB, right? You should distinguish between
> different classes of profiles ... AdobeRGB and sRGB (and others) are
> "working space" profiles, abstract profiles that are grey-balanced and
> defined for a particular gamut width. So you would edit your files in
> those. When you look at the file on the screen it's being adjusted by
> your monitor ICC profile on the fly so the colors represented by the
> RGB values match your specific monitor. This monitor profile is a
> "device specific" profile (as opposed to the non-device specific
> working space profiles, which don't match a specific device). When you
> print with an ICC profile you're translating the RGB values again, this
> time to a device-specific printer profile that hopefully translates the
> numbers so the print looks as close to the monitor as possible. You
> can actually read off these translated numbers if you have a file open
> and apply a soft proof (view > proof setup > custom) and open the Info
> palette and right-click on the second eyedropper and change it to
> 'proof color'.
>
> If this is unclear here's a good link explaining the basics of
> translating the RGB triplets to different values for different devices
> using the ICC profiles ...
> http://www.creativepro.com/story/feature/13605.html
>
> Bill

When dealing with ICC profiles, PS has its own lingo such as attach,
assign, convert and soft proof (and more?). By "change to a different
profile", the original poster could have meant one or more of these.
While the lingo are well explained in the PS manual, they are scattered
all over the place. PS should also publish a dictionary or an
encyclopedia. Sigh.