Soft proofing with RT-5

Software RawTherapee
1

Searching RawPedia, one finds:

Monitor Profile and Soft-Proofing:
One can also enable soft-proofing of the preview. This will show you what your image will look like once it gets transformed by the output profile in the “Color Management” tool. If you want to adjust an image for printing and you have an ICC profile for your printer-paper combination you could set that as your output profile,

Now, with the advent of RT-5, we find a new field in the Color Management tab of the Preferences window.:

So this naturally brings up the question: For the purpose of soft-proofing, where should one specify the ICC profile of the printer/paper combination?

  • Here under Preferences>Color Management.

  • Tools>Color tab>Color Management>Output profile (as suggested by above extract)

  • Both of above.

Enquiring minds need to know :smiley:

2

ping @Hombre He should know :slight_smile:

3

@heckflosse Thanks for reply. Hopefully @Hombre will see and respond.

4

My fault, I didn’t found time to update RawPedia (and then fix issue #3664). The documentation should be fixed by tomorrow.

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5

English version of Rawpedia updated, now match your guess. I’ve opened a new branch name “output-profiles” where you can now select output profiles of the “display” (as actually) and “output” (new) device class, but only if they have an RGB color-space.

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hi, how do you tell if a profile is RGB or not please? Could you perhaps see if this one is RGB? -

(I’d like to send some files off for printing one day using this, depending on if/when your new branch is available to Ubuntu reasonably painlessly)
Thanks

7

There are several ways to examine an ICC profile, including:

exiftool
iccToXml
icc_examin and/or colord
ArgyllCMS “iccdump”

Some details:

If you have exiftool installed, just type at the command line:
exiftool name-of-file.icc

The DC-Colour-labs-Frontier-Glossy.icc profile shows the following:

$ exiftool DC-Colour-labs-Frontier-Glossy.icc
ExifTool Version Number         : 10.36                                                                                                                       
File Name                       : DC-Colour-labs-Frontier-Glossy.icc                                                                                          
Directory                       : .                                                                                                                           
File Size                       : 1424 kB
File Modification Date/Time     : 2017:02:27 09:54:44-05:00
File Access Date/Time           : 2017:02:27 09:54:43-05:00
File Inode Change Date/Time     : 2017:02:27 09:54:44-05:00
File Permissions                : rw-r--r--
File Type                       : ICC
File Type Extension             : icc
MIME Type                       : application/vnd.iccprofile
Profile CMM Type                : APPL
Profile Version                 : 2.4.0
Profile Class                   : Output Device Profile
Color Space Data                : RGB
Profile Connection Space        : Lab
Profile Date Time               : 2013:07:29 12:57:51
Profile File Signature          : acsp
Primary Platform                : Microsoft Corporation
CMM Flags                       : Not Embedded, Independent
Device Manufacturer             :
Device Model                    :
Device Attributes               : Reflective, Glossy, Positive, Color
Rendering Intent                : Perceptual
Connection Space Illuminant     : 0.9642 1 0.82491
Profile Creator                 : LOGO
Profile ID                      : 0
Profile Copyright               : Copyright by LOGO GmbH, Steinfurt
Profile Description             : DC Colour labs Frontier Glossy
Chromatic Adaptation            : 1 0 0 0 1 0 0 0 1
Media White Point               : 0.79001 0.81424 0.72165
A To B1                         : (Binary data 221806 bytes, use -b option to extract)
B To A1                         : (Binary data 221842 bytes, use -b option to extract)
A To B0                         : (Binary data 221806 bytes, use -b option to extract)
B To A0                         : (Binary data 221842 bytes, use -b option to extract)
A To B2                         : (Binary data 221806 bytes, use -b option to extract)
B To A2                         : (Binary data 221842 bytes, use -b option to extract)
Gamut                           : (Binary data 76038 bytes, use -b option to extract)

The relevant line is this:
Color Space Data : RGB

So yes, it’s an RGB profile.

If you have iccXml installed, this command will (usually, but sometimes the command fails because it can’t read the icc profile) turn your icc profile into a human-readable XML file:

iccToXml name-of-profile.icc name-of-profile.xml

In this case examine the header information in the xml file, and if it’s an RGB profile, you’ll see something like this: <DataColourSpace>RGB </DataColourSpace>

  <Header>
    <PreferredCMMType>APPL</PreferredCMMType>
    <ProfileVersion>2.40</ProfileVersion>
    <ProfileDeviceClass>prtr</ProfileDeviceClass>
    <DataColourSpace>RGB </DataColourSpace>
    <PCS>Lab </PCS>
    <CreationDateTime>2013-07-29T12:57:51</CreationDateTime>
    <PrimaryPlatform>MSFT</PrimaryPlatform>
    <ProfileFlags EmbeddedInFile="false" UseWithEmbeddedDataOnly="false"/>
    <DeviceAttributes ReflectiveOrTransparency="reflective" GlossyOrMatte="glossy" MediaPolarity="positive" MediaColour="colour"/>
    <RenderingIntent>Perceptual</RenderingIntent>
    <PCSIlluminant>
      <XYZNumber X="0.96420288" Y="1.00000000" Z="0.82490540"/>
    </PCSIlluminant>
    <ProfileCreator>LOGO</ProfileCreator>
  </Header>

Three: If you have icc_examin (http://www.oyranos.org/icc-examin/) or colord (colord - Makes color managed hardware work) installed, both of these programs provide UIs for examining ICC profiles.

Four: If it’s a V2 profile (“ProfileVersion”), you can use ArgyllCMS iccdump (iccdump) to examine the profile. So far almost all printer profiles I’ve seen are V2 profiles.

Anyone know of any other software for examining ICC profiles? Preferably free/libre and hopefully also running under Linux?

1 Like
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Oh, wait, two more:

If you are really hard-core, you can use a hex editor to examine ICC profiles. bless is the easiest one to use that I’ve found, but it requires installing mono and gtk.

If you don’t mind running WINE and using software that’s “free” as in beer but not free/libre, the ICC Profile Inspector is really nice: http://color.org/resource2.xalter - look under “Profile viewing and testing”.

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Good evening,
this really puzzles me:
in RawPedia it is said that “you will be able to select your monitor’s color profile in the combo-box under the preview”. On my system, the monitor is calibrated and the monitor profile is used by all applications handling color management.

So why do I have to specify the monitor profile again in RT to have it applied to the preview window??? Or do I mis-understand something here?

Hermann-Josef

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Hey

Monitor profile handling is done on a per-application basis, it’s a question of how that is implemented. Some applications force you to use the monitor profile “installed” by the resident color management system, e.g. colord, which is dumb. Others, such as RawTherapee, don’t rely on a color management system daemon and instead let you choose one manually, or inherit the profile “installed” in some way if that way is supported, which depends on the operating system (you didn’t mention which OS you use). I don’t have time to check the code right now, but IIRC auto-detection only works on Windows, and the _ICC_PROFILE X11 atom is not checked.

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Thanks for your reply, Morgan.

I am using Windows10.

Hermann-Josef

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Many thanks for the profile info @Elle, much appreciated.

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@Hombre

Many thanks for your reply. The latest Rawpedia shows the following under Preferences>Color Management tab>Printer (Soft-Proofing):

You can select here the color profile of your own printer or your print service in order to simulate the rendering of the printed image.

For this to work the printer profile must be copied to an appropriate folder in order to appear in the drop-down list. Can you tell me the proper location for Windows7? (presumably the directory selected at Preferences>Color Management). Rawpedia says: “the directory where ICC profiles can be found”.
I am guessing this does NOT mean the RT folder “iccprofiles>output”
I am using: C:\Windows\System32\spool\drivers\color and this seems to work OK.

It leaves unanswered the question: What profile should/must be specified at Tools>Color tab>Color Management>Output profile (please see my first post in this thread). As it is currently configured RT will not allow me to select my printer (.icc) profile as Output profile even if it is an RGB color space and has been copied to both “iccprofiles>output” and to the directory selected at Preferences>Color Management.

Please forgive me if I am being a bit overly fastidious.

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@mikesan You’re not overly fastidious, I’m just long to answer. don’t have much time and I’m trying to understand that subject the best I can too :).

Yes, the path is C:\Windows\System32\spool\drivers\color for Windows7 and you’re right, you still can’t select the printer profile as output profile.

The output profile to select depends on your workflow, of course. If you want to make further edit in a pro software, you can use a wide gamut color profile (the biggest one is ACES I think) or if you want to prepare your images for printing, you’ll soon be able to select the printer profile (given that it has an RGB color space) if your print service told you so. You can still attach the AdobeRGB profile as output profile even to send you image to your print service, their system should make the transformation themselves from AdobRGB to their printer profile. However using their printer profile for soft-proofing only will let you approximately see the finale rendering (on paper). You won’t be able to see possible artifacts due to the gamma and bit depth problem (i.e. banding in shadows).

I’m pushing the change (which is a minor and safe change) to the dev branch, it’ll be part of RT5.1 once ready.

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User that can build themselves can now use the printer profiles (RGB color space only) as output profile (dev branch).

@Morgan_Hardwood I’ve updated the documentation a bit too fast. It is correct for the dev branch but not for RT5.0.rev1. Should I revert the doc to the official version ?

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Not directly a tool for examining ICC profiles but maybe still interesting for some: You can extract the profile from an image with ImageMagick: convert name-of-image.jpg name-of-profile.icc

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Hombre,

Many thanks for your prompt reply.

It will be great when RT is modified so that I can select my printer profile as output when sending an image for printing. Meanwhile my immediate concern is simply using the soft-proofing capability of RT for final editing of the image. I am going to assume that, for that purpose, I can enter the printer profile at Preferences>Color Management and simply ignore the entry at Tools>Color tab>Color Management>Output profile

Please let me know if this assumption is correct.

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@mikesan It is correct, but depending on the degree of artwork you’re doing with your image, you might have to chose a correct output profile, beyond the narrow sRGB. As said by Marty Maria, the gamut of a printer is generally smaller than sRGB, excepted for some colors like yellow. I think that using a large gamut output profile may be counterproductive because the print service will chose a rendering intent to fit the data into its colorspace. I’d chose AdobeRGB, but your print provider might tell you the best option (or perhaps @Elle ? :slight_smile: ).

PS: reading your comment again, I think I misunderstood it :slight_smile: …

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Actually not a problem for me. I send my images to Costco for printing. Their system is perfectly happy to accept images converted to the color space of their printer profile. So for now I can output such images with P’shop and when RT is changed to allow using their printer profile as Output Profile, I will be in good shape.

Don’t know what comment you may have misunderstood. No matter :slight_smile:

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Thank you for the changes @Hombre. I will revise RawPedia later today, please do not revert. It’s fine to describe how things are in dev not in the latest release, because the alternative is not feasible.