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Feature #11304

Add the possibility to set more options for softproofing

Added by Lack Of Light almost 2 years ago. Updated almost 2 years ago.

Status:
New
Priority:
Low
Assignee:
-
Category:
Darkroom
Target version:
-
Start date:
11/10/2016
Due date:
% Done:

0%

Affected Version:
git master branch
System:
all
bitness:
64-bit
hardware architecture:
amd64/x86

Description

Saal Digital is a popular German photo lab that develops digital pictures in high quality. They accept colour-managed JPGs with included AdobeRGB or sRGB colour profile. (German website: http://www.saal-digital.de; English website: http://www.saal-digital.co.uk/)

They also supply ICC-profiles (http://www.saal-digital.co.uk/service/icc-profile-test-print/) that I am using for soft proofing in Darktable. I have saved the ICC profiles at ~/.config/darktable/color/out and it is possible to choose those ICC profiles as Softproof colour profile in Darktable / Darkroom.

The problem is that the pictures looks dull and like covered with a grey shadow when viewed with different of the softproofing Saal ICC profiles. One reason might be that Saal requires not only to include the ICC profiles into your picture development program (it seems like they focus on Lightroom and Photoshop) but you also have to set the following five parameters each individual ICC profile that I can't do in Darktable:
- Preserve CMYK Numbers
- Preserve RGB Numbers
- Rendering Intent (can be set in Darktable, when "always use LittleCMS 2 to apply output color profile" in "Darktable preferences / core options" is checked)
- Black Point Compensation
- Simulate Paper Color

Would it be possible to add a feature in Darktable that lets me configure all five above mentioned parameters for each colour profile that can be used for softproofing in Darktable? All possible values for these five parameters are listed here: http://www.saal-digital.co.uk/service/icc-profile-test-print/

At the moment, softproofing in Darktable in combination with Saal Digital's ICC profiles is useless for me, because the results are not reliable.

I am using Linux Mint 18 Cinnamon.

Attached are the ICC-profiles of Saal Digital.

SaalDigital_ICC.zip (27.5 MB) Lack Of Light, 11/10/2016 10:29 PM

picture_with_softproofing_SaalDigital_Fotobuch_Matt_10-15.png (532 KB) Lack Of Light, 11/11/2016 10:47 AM

picture_with_softproofing_SaalDigital_SoftProof_Fuji.png (570 KB) Lack Of Light, 11/11/2016 10:47 AM

picture_without_softproofing.png (570 KB) Lack Of Light, 11/11/2016 10:47 AM

picture_with_softproofing_SaalDigital_Fotobuch_Glanz_10-15.png (534 KB) Lack Of Light, 11/11/2016 03:03 PM

Lightroom_picture_with_softproofing_SaalDigital_Fotobuch_Glanz_10-15.png (437 KB) Lack Of Light, 11/11/2016 03:36 PM

Lightroom_picture_with_softproofing_SaalDigital_Fotobuch_Matt_10-15.png (435 KB) Lack Of Light, 11/11/2016 03:36 PM

History

#1 Updated by Lack Of Light almost 2 years ago

Sorry, should be a feature, not a bug. Can somebody please change the type of this issue? Thank you very much.

#2 Updated by Tobias Ellinghaus almost 2 years ago

  • System changed from Ubuntu to all
  • Tracker changed from Bug to Feature
  • Subject changed from Add the possibility to set following five parameters for softproofing in Darktable / Darkroom: Preserve CMYK Numbers; Preserve RGB Numbers; Rendering Intent; Black Point Compensation; Simulate Paper Color to Add the possibility to set more options for softproofing
  • Target version deleted (2.2.0)
  • Affected Version changed from 2.0.7 to git master branch

Hmm, I never had problems with the Fuji profile from Saal. And I am not sure what all those options are supposed to do (the two "Preserve" ones).

#3 Updated by Lack Of Light almost 2 years ago

The SaalDigital_SoftProof_Fuji.icc is the only profile that works fine.

I attached some screenshots to illustrate the problem.

picture_without_softproofing.png shows the picture without any softproofing activated in Darkroom.

picture_with_softproofing_SaalDigital_SoftProof_Fuji.png shows the picture with the SaalDigital_SoftProof_Fuji.icc as Soft Proof in Darkroom. This picture is fine, there is only a small difference in the greens of the trees on the right, but that's as expected.

picture_with_softproofing_SaalDigital_Fotobuch_Matt_10-15.png shows the picture with the SaalDigital_Fotobuch_Matt-10-15.icc as Soft Proof in Darkroom. Here you can see the grey shadow that covers the picture. All other Saal icc-files produce a similiar result when used for softproofing in Darkroom, except the above mentioned SaalDigital_SoftProof_Fuji.icc.

Please let me know, if you need further information to clarify my feature request.

#4 Updated by Pascal Obry almost 2 years ago

Have you tried the same profile on say Lightroom?

IIRC when I was using Lightroom I also add this dull tone when using a matt-paper profile. Would be nice to double check that.

#5 Updated by Lack Of Light almost 2 years ago

The dull tone not only occurs with matte papers. Attached is a screenshot picture_with_softproofing_SaalDigital_Fotobuch_Glanz_10-15.png that shows the same problem with Saal's SaalDigital_Fotobuch_Glanz_10-15.icc softproof for glossy paper activated in Darkroom.

I currently have no running Lightroom version, but I'm trying to supply you with Lightroom softproofing screenshots as soon as possible.

#6 Updated by Lack Of Light almost 2 years ago

Attached are some screenshots of Lightroom 5.7 running on Windows 7 in a virtual machine on the same computer as Darktable is installed.

I imported the same picture including its xmp-file that I have used in Darktable.

Lightroom_picture_with_softproofing_SaalDigital_Fotobuch_Glanz_10-15.png shows the picture with the SaalDigital_Fotobuch_Glanz-10-15.icc as Soft Proof in Lightroom 5.7.
Lightroom_picture_with_softproofing_SaalDigital_Fotobuch_Matt_10-15.png shows the picture with the SaalDigital_Fotobuch_Matt-10-15.icc as Soft Proof in Lightroom 5.7.

They look different to the ones in Darktable / Darkroom.

Do you need any additional information?

#7 Updated by Pascal Obry almost 2 years ago

First... I'm no expert on this, so read with that in mind.

I had a quick look at what dt does for softproofing. We are using relative-colometric + black-point-compensation which is what LittleCMS does recommend for softproofing.

Black point compensation
c)
Use relative colorimetric + black point compensation. This is the discussion theme. Colors 
are unmoved *except* gray balance  that is scaled in order to accommodate to  the 
dynamic range of new  media. Is not a smart CMM, but a fist step letting the CMM to do  
some remapping.

We can also read:

Also, there is another parameter for specifying the intent for the
 proof. The Intent here represents the intent the user will select 
when printing, and the proofing intent represent the intent system is
using  for  showing  the  proofed  color.  Since  some  printers  can  archive
  colors  that  displays  cannot render (darker ones) some gamut
-remapping must
 be done to accommodate such colors. Normally 
INTENT_ABSOLUTE_COLORIMETRIC
 is to be used: it is likely the user wants to see the exact colors 
on screen, cutting off these unrepresentable colors.  

The interesting part is "cannot render (darker ones) some gamut remapping...". I've always taken the fact that the darker tones are "washed" is part of the game as it is often said that printer can't render darker/black tones very well. Now Lightroom seems to be immune to that, not sure who is right here!

I have tied the combo absolute-colorimtric + black-point-compensation but the result is even "worst" (more washed) for me.

#8 Updated by Pascal Obry almost 2 years ago

All this to say that giving a way to users to change all those parameters won't help. It seems that there is no combination to get a result similar to what you've seen on Lightroom.

#9 Updated by Tobias Ellinghaus almost 2 years ago

There are some open questions here:

  • Do we know that the washed out look isn't correct?
  • Did you profile/calibrate your monitor? Maybe you are seeing the effect worse than you should due to a wrong/missing/broken display profile?

#10 Updated by Pascal Obry almost 2 years ago

And it looks like some people agrees that washed out pictures are ok and means out-of-gamut color which are impossible to render on the paper.

https://luminous-landscape.com/understanding-soft-proofing/

At least looks like we are not alone.

#11 Updated by Lack Of Light almost 2 years ago

Thank you all for your valuable answers.

Pascal Obry wrote:

I had a quick look at what dt does for softproofing. We are using relative-colometric + black-point-compensation which is what LittleCMS does recommend for softproofing.

Thank you. Good to know what values Darktable uses for this parameters.

Tobias Ellinghaus wrote:

  • Do we know that the washed out look isn't correct?

Well, at least the picture looks different on the same monitor and same colour profile in Lightroom as it does in Darktable.

Tobias Ellinghaus wrote:

  • Did you profile/calibrate your monitor? Maybe you are seeing the effect worse than you should due to a wrong/missing/broken display profile?

Yes, the Monitor is calibrated with x-rite i1 Display and Linux Mint colour profiling (Color).

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