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I don't understand how DPP does color management

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GregS2

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I can't find a dedicated forum for DPP, so I'll just ask here - I hope it's ok. (I am using an EOS M, but that's not all that relevant for my problem)

In DPP, with a RAW file open, if I simply change my Work Color Space, the image changes appearance. This isn't what I expected - I expected one of two things to occur: DPP would re-convert from the RAW image into the new work space, OR, it would convert from the current work space into the new work space. If it were doing either, I would not expect any change in appearance, because the image in question is not a very wide gamut image. I kind of get the impression that DPP is much simpler than I initially thought - I don't think DPP has a proper separation of the "work" space from the image space - they are one and the same. I hope I'm wrong about this.

I've read the manual, and I've read this: http://support-th.canon-asia.com/contents/TH/EN/8000785601.html but it all seems so vague!

Does anyone have a REALLY thorough understanding of how DPP does colour management?

Thanks,
Greg.
P.S There doesn't seem to be a tag for DPP - there are MANY software tags, but DPP isn't in the list. Strange.
 
That sounds like it's working as it should. The RAW files have no color space, DPP displays data from the RAW file in the selected color space (and as it would appear after export). When you change the color space the RAW file will be reinterpreted into the new color space. It would (or at least can) change due to the different colors available. For example, say you're in sRGB and DPP has to map a pixel to an sRGB color that is "close enough". Then you change to AdobeRGB and it now finds a more appropriate color to map that pixel to - the image appearance changes.

That's my understanding, maybe others can provide more details or correct me if i'm wrong.
 
You can set DPP to 1 of 5 color spaces. By default it is set to sRGB which has the smallest gamut. Adobe RGB has a larger gamut, or more colors available. There are numerous depictions of the various color spaces on the web. The link just tells you how to change your default color space, but you can also change your work space in the Adjustment menu.

Do you profile your monitor? Is it capable of displaying a color space other than sRGB? Do you plan on printing?

You see it's not so simple. My monitor is profiled for AdobeRGB, so my camera and DPP4 is set to that same color space. But your situation might be entirely different.

You'll find a plethora of opinions on the Retouching forum.
 
mdmarqphoto said:
That sounds like it's working as it should. The RAW files have no color space, DPP displays data from the RAW file in the selected color space (and as it would appear after export). When you change the color space the RAW file will be reinterpreted into the new color space.
Click to expand...
Thanks. (and sorry for the delay in replying - I expected to receive an email notification, but didn't)

RAW files must, somehow, be interpreted in conjunction with some kind of a "color space". I.e, each camera sensor has it's own characteristics, and if accurate color is to be achieved, there has to be some kind of a profile for the camera. If what you say is true, that the raw image data is simply assumed to be in the currently selected work space, then I don't think this is the best way for a raw converter to work, and I hope that you're wrong. (although, from the behaviour I've seen, I think there's a good chance you are correct, unfortunately). Since making this post, I've been digging around in the DxO forums, and over there, they say that digital cameras typically have very wide gamuts - wider even than Adobe RGB. It seems that DxO (in PhotoLab, for example) actually create their own profiles for the cameras, but they're not necessarily in the form of standard ICC profiles. When a raw image is opened, the DxO "profile" is used to correctly interpret the raw data, and then of course display it to the monitor with whatever monitor profile is in use. Someone actually did a test with a very wide gamut photo, to convince themselves that whatever DxO used as the "working space" was wide enough to retain the gamut of the photo, and it did. Here's the thread: http://forum.dxo.com/index.php/topic,10127.msg58116/topicseen.html#msg58116
mdmarqphoto said:
For example, say you're in sRGB and DPP has to map a pixel to an sRGB color that is "close enough". Then you change to AdobeRGB and it now finds a more appropriate color to map that pixel to - the image appearance changes.

That's my understanding, maybe others can provide more details or correct me if i'm wrong.
Click to expand...
This kind of contradicts what you said above. If, when we change the work space, DPP simply keeps the existing image data, but uses the new color space in conjunction with that data, then of course the colors will change, because the same image data will have a different meaning in the new color space. If it CONVERTED to the new space (which is what I thought it might do), then yes, some colors MAY change, if the new color space can't represent the original colors. As I said, my test image wasn't vivid, and I would not expect any substantial changes, if it were doing a color space conversion. Complicating all this is the monitor in use - the monitor has to be good enough to show the colors accurately in the before & after profiles, of course.

P.S I like PhotoLab!
 
Which DPP version do you use? What you say sounds familiar but I just checked and cannot replicate that behavior. There is a small asterisk there saying that the new settings take effect after restarting. When I restart, I cannot see changes but I am comparing images by memory.

Also, make sure that the OS profile is selected.
 
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J A C S: I'm using DPP 4.7.1.0. i am using the Adjustment > Work Color Space menu command to change the work space. The colors definitely change immediately when I do that.
 
What IGregS2 said:
J A C S: I'm using DPP 4.7.1.0. i am using the Adjustment > Work Color Space menu command to change the work space. The colors definitely change immediately when I do that.
Click to expand...
OK, I see what you mean now. I was looking under Preferences.

What I see is a change of the tonality (the curve) or the contrast, not the colors. It is an old Canon thing. It was there in their Zoom Browser which had a RAW converter in the past. I do not know enough about the specifications of different color spaces but I guess it is a matter of taste during the conversion to sRGB.
 
GregS2 said:
mdmarqphoto said:
That sounds like it's working as it should. The RAW files have no color space, DPP displays data from the RAW file in the selected color space (and as it would appear after export). When you change the color space the RAW file will be reinterpreted into the new color space.
Click to expand...
Thanks. (and sorry for the delay in replying - I expected to receive an email notification, but didn't)

RAW files must, somehow, be interpreted in conjunction with some kind of a "color space". I.e, each camera sensor has it's own characteristics, and if accurate color is to be achieved, there has to be some kind of a profile for the camera. If what you say is true, that the raw image data is simply assumed to be in the currently selected work space, then I don't think this is the best way for a raw converter to work, and I hope that you're wrong. (although, from the behaviour I've seen, I think there's a good chance you are correct, unfortunately). Since making this post, I've been digging around in the DxO forums, and over there, they say that digital cameras typically have very wide gamuts - wider even than Adobe RGB. It seems that DxO (in PhotoLab, for example) actually create their own profiles for the cameras, but they're not necessarily in the form of standard ICC profiles. When a raw image is opened, the DxO "profile" is used to correctly interpret the raw data, and then of course display it to the monitor with whatever monitor profile is in use. Someone actually did a test with a very wide gamut photo, to convince themselves that whatever DxO used as the "working space" was wide enough to retain the gamut of the photo, and it did. Here's the thread: http://forum.dxo.com/index.php/topic,10127.msg58116/topicseen.html#msg58116
GregS2 said:
For example, say you're in sRGB and DPP has to map a pixel to an sRGB color that is "close enough". Then you change to AdobeRGB and it now finds a more appropriate color to map that pixel to - the image appearance changes.

That's my understanding, maybe others can provide more details or correct me if i'm wrong.
Click to expand...
This kind of contradicts what you said above. If, when we change the work space, DPP simply keeps the existing image data, but uses the new color space in conjunction with that data, then of course the colors will change, because the same image data will have a different meaning in the new color space. If it CONVERTED to the new space (which is what I thought it might do), then yes, some colors MAY change, if the new color space can't represent the original colors. As I said, my test image wasn't vivid, and I would not expect any substantial changes, if it were doing a color space conversion. Complicating all this is the monitor in use - the monitor has to be good enough to show the colors accurately in the before & after profiles, of course.

P.S I like PhotoLab!
Click to expand...
I don't see how that contradicts what I said. The data in the RAW file is interpreted by DPP with Canon proprietary info (and reverse engineered by others) and then mapped to the chosen color space which is based on your desired final display device or print media (or simply your editing workspace preference). Changing the color space will remap the colors and they can change on screen. Also important is the color gamut of your display, and the OS color settings. I think the word "converted" may not be applicable here, because the color space defined to display/print the image isn't set in stone until you actually export the file to a JPG or TIF. Up to that point you haven't really converted anything.
 
mdmarqphoto: you have now contradicted yourself again - if color is "mapped" to a different color space, that IS a conversion. If a given set of image data is re-INTERPRETED in a different color space, without changing the data, that is the same as "assigning" a different color space. Your reply doesn't help me in any way, I'm sorry.
 
(btw, I've contacted Canon. If I get any help, I'll post here, with their permission l
 
GregS2 said:
mdmarqphoto: you have now contradicted yourself again - if color is "mapped" to a different color space, that IS a conversion. If a given set of image data is re-INTERPRETED in a different color space, without changing the data, that is the same as "assigning" a different color space. Your reply doesn't help me in any way, I'm sorry.
Click to expand...
I don't think I've contradicted myself at all. There is no "conversion" going on with the data. Read your sentence above, it says the same thing I have been saying - "assigning a different color space" is just the mapping of RAW file values to a currently selected color space. Once the RAW data is "interpreted" (by DPP or whatever) and the values are "assigned" within the desired color space...they have been "mapped". The act of mapping is dynamic. As in one of my earlier examples, if you edit and export a file on your AdobeRGB configured system and someone else views it on their sRGB-only system, the color values within the JPG file will be mapped into the sRGB color space for viewing...and not appear as you intended. If you then move that same file to a system/viewer that can display the AdobeRGB color space, the file will appear as intended. No conversion is happening, just a different mapping of the color data within the file at the time of viewing.

Maybe I'm not explaining it well enough...I'll let someone else give it a try.
 
Whenever a COLOR in one color space is to be represented in a different color space, that is a "conversion", or a "mapping". If you're saying it's on the fly, then I agree, your post then starts to make more sense.

Now, this is important - my colors, I very strongly suspect, are within gamut of both the work spaces I am switching between. (as I said at the outset) There should NOT be any change, but there is. In a different application (Affinity Photo), I have done a conversion, using a much more vivid test image in Adobe RGB (I converted to sRGB) and I still can't see the slightest difference, perhaps because my monitor simply can't show me the difference. This is why I still think DPP is NOT actually "mapping" the proprietry representation of the colors into my new work space, which is a problem.

Greg.
 
GregS2 said:
Whenever a COLOR in one color space is to be represented in a different color space, that is a "conversion", or a "mapping". If you're saying it's on the fly, then I agree, your post then starts to make more sense.

Now, this is important - my colors, I very strongly suspect, are within gamut of both the work spaces I am switching between. (as I said at the outset) There should NOT be any change, but there is. In a different application (Affinity Photo), I have done a conversion, using a much more vivid test image in Adobe RGB (I converted to sRGB) and I still can't see the slightest difference, perhaps because my monitor simply can't show me the difference. This is why I still think DPP is NOT actually "mapping" the proprietry representation of the colors into my new work space, which is a problem.
Click to expand...
There are many ways to do that mapping. For example:

http://www.cambridgeincolour.com/tutorials/color-space-conversion.htm

Loading…

www.cambridgeincolour.com

On the right, the colors will/might be squeezed even if the gamut is small. It does not need to be that way - the application may squeeze the actual gamut only, not the largest possible.

In my experience, DPP compresses the tonal curve, not the colors.
 
I asked 2 questions. Do you profile your monitor; can it display any color space other than sRGB.

No answer.

Let's assume he doesn't know.

DxO tells him his sensor can capture more colors than AdobeRGB but:

(1. That doesn't mean he can view them.

(2. Not every scene has such a broad range

Further, unless you print it probably doesn't matter, and even then...
 
Yes, I know there are many ways. I'm assuming Affinity Photo does a Relative Colorimetric using the simple Document | Convert Profile command that I used. (it has proofing as well, which I haven't tried yet) It does not profile any obvious way to change the intent using the method I used.
 
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I asked whether anyone here has a thorough understanding of how DPP does colour management, and I'm going to assume that you don't.
 
That comment puts you squarely in the Troll Bin.

Why don't you answer 2 simple questions?

You can't, you won't, you're a Troll.
 
GregS2 said:
Yes, I know there are many ways. I'm assuming Affinity Photo does a Relative Colorimetric using the simple Document | Convert Profile command that I used. (it has proofing as well, which I haven't tried yet) It does not profile any obvious way to change the intent using the method I used.
Click to expand...
Different applications do it differently. It is just the way DPP does it, and that's it. Again, it changes the curve, not the colors.
 
J A C S said:
What I see is a change of the tonality (the curve) or the contrast, not the colors. It is an old Canon thing. It was there in their Zoom Browser which had a RAW converter in the past. I do not know enough about the specifications of different color spaces but I guess it is a matter of taste during the conversion to sRGB.
Click to expand...
You know what? I think you could be right. I took a more vivid photo (in raw) and then looked carefully at how the image changed when switching back and forth between Adobe RGB and sRGB. I have to agree with you that it's only a subtle change. I then exported the image to a JPEG, in Adobe RGB, and loaded it in Affinity Photo. When I switch back and forth in this app (using the Assign Profile command), the difference is more pronounced - the colours really do appear less saturated when switching from Adobe to sRGB. (which is to be expected).

So my initial assumption is probably incorrect, which is good news - setting the work space in DPP probably DOES result in the "raw" image being converted/mapped to the new work space.

Just btw, I notice that it is ONLY sRGB that results in the tone shift - if I select any of the other choices (Apple, Wide Gamut, ColorMatch), I can't see any change whatsoever. This seems a bit odd.

There's another thing that is a bit confusing. In the DPP preferences, there is an option to set the work space to "as shot". Taken as read, this implies that the camera places the raw data into the color space set in the camera, but it seems to be well accepted that this is not the case - the in-camera setting only affects the JPEG preview that is embedded in the raw file, and has no effect on the raw data proper.
 
I get different results, switching between different work spaces in DPP, depending on whether I explicitly set the monitor profile in DPP, or, whether I select "Use OS Settings" for the monitor profile, despite the fact that I am using exactly the same monitor profile in both situations. The DPP manual says:

"If you select [Use the OS Settings], the color profile set in Windows will also be applied in DPP"

So, I would expect the behaviour to be identical. Does "Use the OS Settings" really mean "use Windows for color management"?
 
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