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Roger Simon

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  1. Like
    Roger Simon got a reaction from Jose A in Color management   
    @owenr

    Again, you’re correct.
    I simply had opened both preview images in ColorSync-Utility and within this app, both have sRGB assigned. But obviously, this assignment is made by ColorSync-Util itself. (lesson learned: always use PS).
     
    @owenr, @R C-R,
    Can verify, that AP either *assignes* or *converts* unprofiled jpgs to a) the set RGB color profile or b) sRGB, based on what the user sets in the application’s preferences.
    With unprofiled png however, AP *always assigns* the RGB Colour Profile set in Preferences, no matter if „Convert” is checked or not.
    (At least, that’s the behaviour I’m experiencing here on OSX 10.11.6).
    These behaviours -in my eyes- are unwanted, as the user has no chance to intervene.
    (And I haven’t checked the behaviour for unprofiled tifs…)
    Say, a jpeg file originates in AdobeRGB but does not have an embedded profile.
    If AP is set to sRGB (or conversion is turned off), the file would open with wrong colours, as sRGB would be assumed as the source colour space.
    If AP is set to convert, then the application would do this error possibly twice: first, it would wrongly assume sRGB as colour space and then would do a conversion to i.e. AdobeRGB or ProPhotoRGB based on these wrong colours.
    Profile Warnings btw now seem to me pretty random. During my tests, I was experiencing all sorts of combinations with/without warnings either on jpg or png.
    (But probably AP just does not like when preferences are switched that often, even if the application is closed in between).
     
    @ Jose A:
    Hardware calibration: the measured color values from the colorimeter are written into the LUT of the monitor.
    On OSX, you can switch between different hardware calibrated profiles either by the buttons on the monitor or via OSX System Preferences.
    I do not know, how this is exactly handled on Windows though.
    Software calibration: An icc profile is generated and used on System Level to overwrite the GPU’s color rendering. Depending on the monitor used and its capabilities (i.e. whitepoint setting, R-G-B sliders available or not), this leads to more or less good, but always reduced colour rendition (due to whitepoint setting). It’s the only way available on most displays.
    As far as I understood, your monitor is actually used with the default factory profiles. This cannot be seen as hardware calibrated, as long as these profiles aren’t verified with a colorimeter. At least during the next 2-3 months, colours will have changed.
     
    >>> Your issue with sRGB:
    I’m wondering if this is probably an actual limitation of the Windows version of AP?
    On OSX, it’s possible to choose any installed icc profile as the document’s colour space right from the beginning. I’m actually asking myself, if your way can result in correct colours as you are switching from a smaller to a wider colour space. If colours would already be present in the file, these colours would be desaturated that way. But I have to admit that I don’t know what actually happens to an empty file.
     
    >>> ProPhotoRGB
    Adobe choses that Colour Space as it is wide enough to contain every colour that a camera can produce and will ever produce in the future. This is the reason, why they left their own AdobeRGB. Working right from the beginning in ProPhoto is a good way, but one has to be aware that one most likely needs to reduce to a smaller Gamut on export, depending on the output target.
    If you convert a sRGB file into ProPhotoRGB, you can do more destructive work on that file. It’s similar as converting from 8-bit into 32-bit. You don’t get more information into the file, you can just destruct it more.
    >>> Rendering intents are especially important when converting from RGB to CMYK for print.
  2. Like
    Roger Simon got a reaction from Leigh in Color management   
    Hello Jose A,
     
    from re-reading your posts above, I try to recap your settings:
     
    -You have Windows set to AdobeRGB on OS level.
    (Wouldn’t you need to set your calibrated monitor’s profile here? This is the way it works on OSX/MacOS. The calibration software should offer this profile to the OS).
     
    -You develop in LR (using ProPhotoRGB) and then open up in AP (RGB Colour Profile set to ProPhotoRGB in Applicaton’s Prefs).
     
    From your screenshots, it seems that LR is embedding ProPhotoRGB into the exported images and AP reads that profile.
    (You would notice a different Profile in the document window, if i.e. AdobeRGB or sRGB would be embedded, as AP would then read one of these profiles instead appliying ProPhotoRGB).
    [I was wondering why you would need to download the ProPhoto profile, but this might be down to differences in Windows and OSX/MacOS colour management].
    Just as an assumption: if LR would export without embedded profile, AP would automatically assign ProPhotoRGB, even if you had worked in a different colour space in LR. That would lead to false colours.
     
    ProPhotoRGB has theoretical advantages as a working colour space as it is simply extremely wide and data will never be clipped by this colour space.
    (In practice, you are down to AdobeRGB, just because this is about the maximum that you will ever see onscreen. A further limitation would be the colour space available i.e. within the colour settings of your camera. Most are limited to sRGB, higher quality cameras support AdobeRGB, some work with true 16-bit colour depth.
    But no camera is able to fully use ProPhotoRGB, and no monitor is able to represent that colour space).
     
     
    This is generally correct, it reflects the actual embedded colour profile of the opened file. [except: untagged file issue]
    (If you open an image with embedded sRGB profile, sRGB will be shown regardless of your Preference settings).
     
    Your idea with the different colour conversions is also correct, so I’m assuming that you already have verified, that your Export settings in LR match your colour settings in AP (i.e. Rendering Intent).
     
    As long as no Affinity developer joins this thread, I would advise you to send in a bug report on that issue, so that you most likely will get help directly from the development team.
  3. Like
    Roger Simon got a reaction from Leigh in Color management   
    Hello Jose A,
     
    from re-reading your posts above, I try to recap your settings:
     
    -You have Windows set to AdobeRGB on OS level.
    (Wouldn’t you need to set your calibrated monitor’s profile here? This is the way it works on OSX/MacOS. The calibration software should offer this profile to the OS).
     
    -You develop in LR (using ProPhotoRGB) and then open up in AP (RGB Colour Profile set to ProPhotoRGB in Applicaton’s Prefs).
     
    From your screenshots, it seems that LR is embedding ProPhotoRGB into the exported images and AP reads that profile.
    (You would notice a different Profile in the document window, if i.e. AdobeRGB or sRGB would be embedded, as AP would then read one of these profiles instead appliying ProPhotoRGB).
    [I was wondering why you would need to download the ProPhoto profile, but this might be down to differences in Windows and OSX/MacOS colour management].
    Just as an assumption: if LR would export without embedded profile, AP would automatically assign ProPhotoRGB, even if you had worked in a different colour space in LR. That would lead to false colours.
     
    ProPhotoRGB has theoretical advantages as a working colour space as it is simply extremely wide and data will never be clipped by this colour space.
    (In practice, you are down to AdobeRGB, just because this is about the maximum that you will ever see onscreen. A further limitation would be the colour space available i.e. within the colour settings of your camera. Most are limited to sRGB, higher quality cameras support AdobeRGB, some work with true 16-bit colour depth.
    But no camera is able to fully use ProPhotoRGB, and no monitor is able to represent that colour space).
     
     
    This is generally correct, it reflects the actual embedded colour profile of the opened file. [except: untagged file issue]
    (If you open an image with embedded sRGB profile, sRGB will be shown regardless of your Preference settings).
     
    Your idea with the different colour conversions is also correct, so I’m assuming that you already have verified, that your Export settings in LR match your colour settings in AP (i.e. Rendering Intent).
     
    As long as no Affinity developer joins this thread, I would advise you to send in a bug report on that issue, so that you most likely will get help directly from the development team.
  4. Like
    Roger Simon got a reaction from Jose A in Color management   
    Hello Jose A,
     
    unfortunately, I’m no expert regarding colour management on Windows.
    From what you are describing and from the look of your screenshots however, it seems to me that AP might be rendering the image onscreen in sRGB, while it might render correctly in LR.
    Afaik, Windows has sRGB deeply integrated into the OS, so the solution could lie in the colour settings on the OS level.
    AP probably uses this information while LR has its own solution.
     
    If your monitor is calibrated, you need to make sure, that Windows uses this profile for onscreen display.
    (My only experience here was during Windows Vista, which was a true nightmare regarding colour management on OS level and very hard to understand for someone that worked on MacOS ever since).
     
    Did you verify that your file has a colour space tagged to it?
    Because AP automatically applies the RGB colour profile from the App’s Preferences to untagged files without enquiry.
     
    Sorry for being no big help here, but hopefully there is at least some information that gives you some input to continue to get closer to a solution.
  5. Like
    Roger Simon got a reaction from anon2 in RGB colour management anomalies   
    Hello owenr,
     
    again, you're right: as I could verify a similar issue that I have within a 3D DCC app by simply opening the screenshots via QuickLook or Preview.app, I just used those while checking this issue here with Affinity Photo.
    Now, in PS the differences are there.
    I'm attaching a screen grab which contains my Monitor's Profile and therefore the maximum discrepancy between Image Display Area and Navigator panel, that I experience here.
    As one can see, all colors are way off, only the greyscale patterns are close to each other.
     
     
     

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