Difference between "Convert Format / ICC Profile" and "Assign ICC Profile"?

[lphilpot]

(Searching revealed several loosely related existing posts on this topic but I found no answers, so I'm asking)

Although I'm sure there are corners where I'm fuzzy, I pretty much grasp color models, spaces, gamuts, profiles, soft proofing, etc. at a working level. Per the subject, I'm asking about the Document | Convert Format / ICC Profile and Document | Assign ICC Profile menu choices in the context of what Photo actually does.

I've looked through the Help and found only a very little specific info. Maybe it's there and I'm missing it, but without a per-menu-choice index it can be challenging to find information on a specific operation.

https://affinity.help/photo2/en-US.lproj/index.html?page=pages/Clr/ClrProfiles.html?title=Color management

Much of what's in Help sounds related to soft-proofing based on the language, which is a different matter. The "Assigning Color Profiles" section at the link above uses both "color profile" and "working color space" somewhat interchangeably.

For example:

• Document | Convert Format / ICC Profile
  It says this will "change the document's color profile". Does this mean it will actually change the color space? That's what it looks like based on the dialog box. The profile is what describes and documents the space.
• Document | Assign ICC Profile
  Nothing found. Does this refer to simply writing a profile to metadata?

...and as long as I'm asking...

• File | Import ICC Profile
  Nothing found. Does selecting a profile here simply make it available in the two above dialog boxes? If so, how do we edit the list afterward if necessary?

At this point it's mostly curiosity. I raw-develop and save in ProPhoto (separate app), TIFF-edit (with AP) in ROMM RGB -- i.e., ~ProPhoto -- then JPG-export in sRGB as the last step. So my workflow is OK, I'm just trying to understand what AP does.

Thanks.

[walt.farrell]

As I understand it:

• Convert: Each pixel of your document has a particular color value, in the current profile X. After conversion to profile Y, each pixel has a new value, trying to keep its perceptual color the same relative to the other colors. Thus, the conversion tries to maintain the same appearance of the document, to the extent possible.
   
• Assign: The pixel color values are not changed. Instead, their existing values are re-interpreted according to profile Y. The document appearance is likely to change more.

File > Import ICC Profile: Yes, it just makes it available. I have no idea how you'd edit the list to remove something, but my guess is you'd need to find the folder where the app saved it and delete it from the file system. Alternatively, you could of course simply add it to your system in the first place, and then it would be available to all applications and you'd know for sure where it was  

[lacerto]

Obsolete.

[lphilpot]

@walt.farrell - So "Assign" sounds more like a device profile change than an image change (if the image data isn't actually altered).

Regarding the profiles available on a system, I'd just be more happy if software in general would differentiate between device profiles and color (space) profiles. I see far too often where diaglog / pick-lists display both when one or the other type is inappropriate (e.g., showing a display profile in a list for selecting an image color space). The dialogs need to either display only the right type or have two lists, IMO.

Thanks.

[lphilpot]

6 minutes ago, lacerto said:

...the locations are app specific and also different depending on whether the app was purchased directly from Apple or Microsoft Store (version 2 apps might further complicate the situation depending on whether the default or an alternative MSI installer was used for installation of the app).

Well, given the MS Appstore versions are MSIX installers, they'll have a consistent install location (which is what the bruhaha is all about). Just out of curiosity I'll see if I can track down what's altered by importing a profile.

Thanks for the clarification.

[lphilpot]

Found 'em - Imported profiles are copied to %userprofile%\.affinity\Photo\2.0\profiles on Windows. Presumably they're in a similar location under the user $home on OSX.

Apparently duplicate profiles are not listed twice, presumably as long as the name matches. Or maybe they're just ignored. At any rate, for example, importing ProPhoto (which is already in the list) didn't add a second ProPhoto entry.

To remove imported profiles, delete the *.icc file(s) from this folder and restart Photo.

[VJS]

When I converted an image in AP v1.10, no information was listed regarding dimensions, resolution, color space, color profile, or content creator. The image only had information on created, modified, and content created date/time. I only knew it had been converted to CMYK when I opened it in PS CS6. Is there something else that needs to be selected before converting to a specific space?

[R C-R]

1 hour ago, VJS said:

When I converted an image in AP v1.10, no information was listed regarding dimensions, resolution, color space, color profile, or content creator. The image only had information on created, modified, and content created date/time.

From your screenshot, you are using a Mac, right? If so, what you see listed are the file system attributes of the file. You will need to use some app to see the info you are referring to.

[thomaso]

3 hours ago, VJS said:

no information was listed regarding dimensions, resolution, color space, color profile, or content creator.

Where? On mac the Finder Info / the Preview Info displays them, the creator app excepted.

[VJS]

Yes, a Mac. Yet any other pictures, even screenshots, show all the information. Here's just one example. Why should I have to open it in Preview or any other app when I should just see it under the image in any folder? Not a major issue, just very surprised that the information wasn't automatically generated as it always is when created in a camera or on a computer.

[firstdefence]

@VJS I've just converted a PNG from sRGB IEC1966 2.1 to ProPhoto and the info changes in Finder (Gallery) to display Colour space and Colour profile.

[Dan C]

What are you export settings please @VJS?

I suspect you may not be embedding metadata when exporting the file, meaning this information might not be shown under 'Get Info' on macOS.

[thomaso]

3 hours ago, Dan C said:

I suspect you may not be embedding metadata when exporting the file, meaning this information might not be shown under 'Get Info' on macOS.

I still get these info in Finder & Preview also if "Embed metadata" was disabled in the export options. In particular pixel size + colour space + profile are fundamental info to open / display the file correctly, resolution maybe optional (but obviously is not).

[R C-R]

13 minutes ago, thomaso said:

I still get these info in Finder & Preview also if "Embed metadata" was disabled in the export options. In particular pixel size + colour space + profile are fundamental info to open / display the file correctly, resolution maybe optional (but obviously is not).

For me for JPEGs 'Get Info' almost always shows pixel dimensions & color space, but beyond that it varies tremendously, so for instance only a few show a color profile or resolution. This includes lots of JPEGs I did not create, like some of the desktop pictures built into the macOS, ones that come with third party apps like with the textures DAZ 3D includes, & so on.

[VJS]

You're right, all the info doesn't show in Mac's Get Info window, but it never has that I'm aware of. I go through a folder of photos that I've worked on to make sure all resolution and color space information are correct before placing in Publisher. I'm still stumped as to why random images are generated without this info. I'm moving on to version 2.0.3 in all three apps so hopefully I won't have that issue again.

Thanks everyone for your input.