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Weekly Chatter:ACR Color Space?
Monday September 20, 2004

Section 1: ACR Color Space?






Color Management/WorkFlow > Workflow > ACR Color Space?
























AuthorSubject: ACR Color Space?  
Richard Ripley
Posted on Sat Sep 18, 2004 4:18 PM

Hi folks:

I have been using Adobe Camera Raw 2.2 and Adobe RGB (1998) when processing my RAW files from my Nikon D70.

In the Nikon D70 I have the camera setup to the Adobe RGB color space.

After reading a number of articles, particularly one by Jeff Schewe (Digital Workflow - RAW Processing) I was wondering if I should switch to ProPhoto RGB when I work in ACR?

If I do switch to ProPhoto RGB what should I do when I work in Photoshop CS itself since I have always worked in Adobe RGB (1998)?

If I take a file adjusted in ACR with ProPhoto (Keeping it as 16 bit.) and open it in PS I will get a dialogue asking if I want to convert to Adobe RGB since that is the profile I have set up in PS CS Color Management as my default. Should I convert or should I change my default color management settings to the ProPhoto RGB space?

I have a profile that I use that is setup with Adobe RGB 1998. Obviously, if I change the color management settings I'll need to have a new profile made since I'm working in a new color space. I'm a little confused by all this. Any help and clarification would be greatly appreciated.


Nick Walker
Posted on Sun Sep 19, 2004 6:20 AM

Richard,

You are thinking along the right lines.

If you wish to adopt Pro Photo as your new colour working space for all future images then I would suggest you change your Photoshop colour working space from Adobe RGB 1998 to Pro Photo. This will save the colour settings box popping up after you have converted an image in ACR using the Pro Photo profile.

However all previous images which used an Adobe RGB 1998 profile will open with the embedded profile mismatch dialogue box with options as Photoshop has been instructed to use Pro Photo as your default choice of colour working space.

The beauty of Photoshop is that you can open images in any colour profile regardless of your colour working space setting. You could have three images open at the same time one in Adobe RGB 1998, Pro Photo and colormatch profiles and Photoshop will display each image with its respective profile.

Leave all Adobe RGB 1998 images alone as there is little point in converting them to Pro Photo. Just open them and select "Use the embedded profile (instead of the working space)

Try opening an image with any profile then -
Duplicate that image>Image>convert to profile>select a different profile making sure preview box is on

Photoshop will now be displaying the same image with different profiles.

Retouchers will be sent files from various clients with all manner of profiles which may or may not match the retouchers working space settings. However Photoshop will display them accaurately with their respective profiles.

Nick


Richard Ripley
Posted on Sun Sep 19, 2004 1:02 PM

Hi Nick:

Thanks for the response. I do have a number of questions regarding the ProPhoto color space.

1) Is it worth it to change the color space to Pro Photo from Adobe RGB? What will I gain by changing the space to Pro Photo for my photos?

2) Currently I work in a closed loop system, i.e. I take photos with my D70, download RAW files to computer, use ACR and color correct, move to Photoshop and fine tune and then print on my Epson 2200. I don't plan on printing to anything but an inkjet in the future (Epson 4000, 7600, etc.) and if that is going to be done it will be done by another printer such as Nash Editions. Given my workflow, does it make sense to move to Pro Photo RGB?

3) I think it will but does the profile I have from Imaging Revue for my Epson 2200 and Hanamuhle paper need to be modified if I do change to the Pro Photo RGB space?

I'm sorry but for the longest time I thought I was best served by working in the Adobe RGB 1998 color space. If this was an incorrect assumption I sure would like to know why, with perhaps an explanation of why I should make the switch.

Thanks again for the information!

RR


John MacLean
Posted on Sun Sep 19, 2004 2:10 PM

RR,

See this thread I bookmarked for my own reference: http://www.imagingrevue.com/forums/?thread=000091

Best,
John
www.nmdigital.com


Richard Ripley
Posted on Sun Sep 19, 2004 3:12 PM

Great information though I have to say I'm still a little confused or more accurately unsure as to how to proceed. Could Bruce or Jeff chime in on this one???

So I work in ACR with ProPhoto RGB doing major changes as necessary to White Balance, Exposure, etc. in 16 bit. I open the file (still 16 bit) in PS CS where I have changed my Color Settings to ProPhoto so I won't have to see the Convert Profile dialog all the time. I do minor edits and sharpens, keeping a master file in 16 bit, ProPhoto RGB space. When it comes time to print the image I use the Convert to Profile command, change the profile to Adobe RGB. I then change to 8 bit mode and print to the Epson 2200.

Is this all worth it? Will I get better results with this procedure? After all I'm not using the ProPhoto space to print with. I guess I'm not getting it.

Thanks again for the help!


Bruce Fraser
Posted on Sun Sep 19, 2004 4:03 PM

I stay in ProPhoto all the time�if you're going to convert to Adobe RGB, you may as well do so right off the bat in the raw conversion, because all the extra gamut you've used gets hosed into Adobe RGB in a more-or-less uncontrolled fashion.

The difference I see from staying in ProPhoto is that it does a much better job than Adobe RGB of preserving dark saturated colors. I can then control how these colors get mapped to the print when I go from ProPhoto to printer space by applying adjustment layers to optimize the image for the print process.

If I convert to Adobe RGB, those colors are gone.

There's no need to downsample to 8 bits to print to the Epson 2200. I either send ImagePrint a 16-bit ProPhoto file, suitably optimized via Proof Setup, or I let Photoshop handle the conversion via Print with Preview when I use the Epson driver.


Katrin Eismann
Posted on Sun Sep 19, 2004 4:38 PM

On this thread - if scanning film with an Imacon does it make sense to work
in ProPhoto? Or is ProPhoto primarily a good space for quality ACR files??

Thanks,
Katrin

On 9/19/04 5:05 PM, "IR - Bruce Fraser" <revuemail@imagingrevue.com>
carefully wrote:

> I stay in ProPhoto all the time�if you're going to convert to Adobe RGB, you
> may as well do so right off the bat in the raw conversion, because all the
> extra gamut you've used gets hosed into Adobe RGB in a more-or-less
> uncontrolled fashion.
>
> The difference I see from staying in ProPhoto is that it does a much better
> job than Adobe RGB of preserving dark saturated colors. I can then control how
> these colors get mapped to the print when I go from ProPhoto to printer space
> by applying adjustment layers to optimize the image for the print process.
>
> If I convert to Adobe RGB, those colors are gone.
>
> There's no need to downsample to 8 bits to print to the Epson 2200. I either
> send ImagePrint a 16-bit ProPhoto file, suitably optimized via Proof Setup, or
> I let Photoshop handle the conversion via Print with Preview when I use the
> Epson driver.
> --------------------------------------------------


Richard Ripley
Posted on Sun Sep 19, 2004 4:54 PM

Hello Bruce:

I've been reading a number of the IR forums threads on the ProPhoto issues and I'm beginning to understand what is going on somewhat - finally!

> I stay in ProPhoto all the time�if you're going to convert to Adobe RGB, you may as well do so right off the bat in the raw conversion, because all the extra gamut you've used gets hosed into Adobe RGB in a more-or-less uncontrolled fashion.

When I had a Profile made by Imaging Review it was set up by me with the Adobe RGB 1998 color space. I guess I need to have a new profile made if I make the switch to ProPhoto RGB for the entire image processing that I do. Correct?

> There's no need to downsample to 8 bits to print to the Epson 2200. I either send ImagePrint a 16-bit ProPhoto file, suitably optimized via Proof Setup, or I let Photoshop handle the conversion via Print with Preview when I use the Epson driver.

For some reason I thought I had to downsample to 8 bits when printing to the Epson 2200. I'm glad to know that I don't. Another step saved! Thanks! For web production I guess I should downsample to 8 bit and convert to the sRGB space. Correct?

If I take my PS CS files in ProPhoto space to Nash Editions and Mac Holbert to print larger versions of my 2200 prints will Mac Holbert freak because of the ProPhoto space? Mac recommended the Adobe RGB 1998 space.


Bruce Fraser
Posted on Sun Sep 19, 2004 5:18 PM

-->When I had a Profile made by Imaging Review it was set up by me with the Adobe RGB 1998 color space. I guess I need to have a new profile made if I make the switch to ProPhoto RGB for the entire image processing that I do. Correct?

Profiles are basically lookup tables between Lab and device space. The Perceptual rendering tables always make some assumption about the incoming color, but IR uses Gretag's profiling software, and the assumption made for their perceptual rendering is neither documented nor user-controllable, so I don't see how they could have made a profile set up for Adobe RGB as opposed to some other space. There isn't really anything they could do differently in building the profile, so no, I don't think that's correct.

FWIW, ProPhoto RGB represents the "ideal" output space that ICC color management tries to accommodate, hence its original name, ROMM (Reference Output Medium Metric) RGB. That would be an output with a dMax of 2.8 and a gamut that encompasses about 85% of Lab, so "ideal" is an important caveat�we certainly don't have a real output medium like that�but it's designed to play nicely with ICC's profile connection spaces, Lab and XYZ.

Converting to sRGB, then downsampling to 8-bit (rather than the reverse order) is what I do for web output. You'll have to ask Nash Editions about their tolerance, or lack thereof, for ProPhoto files.


Bruce Fraser
Posted on Sun Sep 19, 2004 5:20 PM

I've been using ProPhoto in conjunction with
Imacon profiles built using Don Hutcheson's
target, with the scanner gamma set to 3.0, for
about 5 years now (through three different Imacon
scanners).

I find it very much worthwhile-your mileage may
vary. I really notice the difference in dark
saturated colors like mahogany, teak, walnut,
chocolate, dark leathers, as well as dark greens
and teals.

I was lucky enough to get paid by Kodak to do a
whole lot of testing on ProPhoto back when it was
still called ROMM RGB (1997-98). After that, I
really didn't see any reason to use any other RGB
space for my own work (I never hand off ProPhoto
files to someone else unless I'm sure they know
how to handle them), so I've been using it ever
since both for scans and for digital captures.

Choosing a working space is a very personal
decision. I don't, particularly, evangelize the
use of ProPhoto, but it has been working very
well for me for a long time...

Best,

Bruce

At 4:38 PM -0500 9/19/04, IR - Katrin Eismann wrote:
>On this thread - if scanning film with an Imacon does it make sense to work
>in ProPhoto? Or is ProPhoto primarily a good space for quality ACR files??
>
>Thanks,
>Katrin
>
>On 9/19/04 5:05 PM, "IR - Bruce Fraser" <revuemail@imagingrevue.com>
>carefully wrote:
>
>> I stay in ProPhoto all the time�if you're going to convert to Adobe RGB, you
>> may as well do so right off the bat in the raw conversion, because all the
>> extra gamut you've used gets hosed into Adobe RGB in a more-or-less
>> uncontrolled fashion.
>>
>> The difference I see from staying in ProPhoto is that it does a much better
>> job than Adobe RGB of preserving dark
>>saturated colors. I can then control how
>> these colors get mapped to the print when I go
>>from ProPhoto to printer space
>> by applying adjustment layers to optimize the image for the print process.
>>
>> If I convert to Adobe RGB, those colors are gone.
>>
>> There's no need to downsample to 8 bits to print to the Epson 2200. I either
>> send ImagePrint a 16-bit ProPhoto file,
>>suitably optimized via Proof Setup, or
>> I let Photoshop handle the conversion via Print with Preview when I use the
>> Epson driver.
>> --------------------------------------------------
>
>--------------------------------------------------


Richard Ripley
Posted on Sun Sep 19, 2004 5:41 PM

Hi Bruce:

I'm reading but I have to say not truly comprehending - in fact I'm getting all fuzzy trying to put my head around what you have said. I guess it's the transition from newbie to dobie or whatever one becomes after being a newbie.

;-)

It is my understanding from what you have written that I can switch to the ProPhoto RGB space and not have to worry about the profile I had created using Adobe RGB 1998 as my working space since the color space doesn't affect the profile that was created or the printed output. So I can setup ACR for ProPhoto, do major edits working in ProPhoto and then do smaller edits in PS CS (16 bit) with the ProPhoto color space and then print (Using 16 bit thank you!) using Print with Preview using the same profile I had Imaging Review create.

I guess I just don't understand color spaces. When I look over the Imaging Review instructions for creating the profile I notice that a Source Space wasn't used for the creation of the profile; the Source Space:Document: in Color Management was set at "Untagged RGB" so I guess the Adobe RGB 1998 space was never part of the profiling equation. Perhaps you could explain a little further and then I might be able to graduate to being a dobie or something a little beyond a newbie?

Thanks very much!!!

Rick
>
> Profiles are basically lookup tables between Lab and device space. The Perceptual rendering tables always make some assumption about the incoming color, but IR uses Gretag's profiling software, and the assumption made for their perceptual rendering is neither documented nor user-controllable, so I don't see how they could have made a profile set up for Adobe RGB as opposed to some other space. There isn't really anything they could do differently in building the profile, so no, I don't think that's correct.



Daniel Marder
Posted on Sun Sep 19, 2004 6:38 PM

Bruce,

> I can then control how these colors get mapped to the print when I go
> from ProPhoto to printer space by applying adjustment layers to
> optimize the image for the print process.

Are you implying a process more systematic and/or controlled than
editing the ProPhoto image until the printer space proof looks OK?

Dan


Louis Bouillon
Posted on Sun Sep 19, 2004 7:57 PM

Bruce
Do you tag your pictures with the in-camera color space such as adobe98 or do you bring your captures tagfree into ACR? If you tag how do you handle the "profile mismatch" warning in PS?
Louis Bouillon


Bruce Fraser
Posted on Sun Sep 19, 2004 10:21 PM

Richard,

-->It is my understanding from what you have written that I can switch to the ProPhoto RGB space and not have to worry about the profile I had created using Adobe RGB 1998 as my working space since the color space doesn't affect the profile that was created or the printed output.

Yes, that's how the system is designed. The input profile and the output profile have no knowledge of one another�that's what differentiates open-loop ICC-based color management from all the old closed-loop proprietary systems. Color is always communicated through the profile connection space.

When you print a profiling target, the object of the exercise is to figure out what the print space actually is, so you send it known device values (RGB or CMYK), then you measure the color that the device values produce. Once you've done that, you know what the printer space is. To do so, it's important that the device values in the profiling target don't get converted�you're sending a known stimulus, and measuring the response.

Daniel,

-->Are you implying a process more systematic and/or controlled than
editing the ProPhoto image until the printer space proof looks OK?

Marginally. I make a duplicate of the ProPhoto RGB image (the image I fell in love with), then I view the original through Proof Setup (the image I can actually print). Then I edit the image viewed through proof setup, and try to make it look as much like the one I fell in love with as the laws of physics will allow.

Louis,

I'm sorry, I don't understand the question. Raw files are grayscale, and cameras don't tag them. I turn off the profile mismatch warning in PS because my policies are set to Preserve Embedded Profiles, and it's not of any particular interest to me if one or another image happens to be in a different working space from my chosen one�all I care about is that it gets displayed correctly. Preserve Embedded Profiles ensures that.





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