Grant Symon wrote:

Can anyone clarify these points for me?

The only way to really cut though all the haze is to take matters into your own hands and carefully test each option out. In the end it may be faster, and at least then you will be certain of what's going on. Graeme Gill.

To me it reads (rather awkwardly, admittedly) like this: Match: convert values so that colors are as faithful as possible (as per rendering intent) in the destination profile's color space to how they looked in the image's original color space, and then embed the destination color space' profile (when saving). Same as Photoshop's Convert to profile. Assign: Disregard the image's original color space (by "original" meaning the embedded one, if any, or Colosync Utility's default of not), and embed the selected profile (when saving) with no value conversation whatsoever. Colors will therefore change. Same as Photoshop's Assign profile. Apply: "Match" to the destination profile, and after that, nevertheless, "assign" the image's original profile. Why would you ever need to do the latter, beats me. Maybe to approximate, in the original color space, how wrong colors would look if their values were mistakenly rendered in the destination color space? Again, why would you ever need to do that :-/ I haven't bothered testing whether my assumptions are correct, though.

El 25/05/2015, a las 16:15, Grant Symon <csync@gsymon.com> escribió:

Hi,

I have a pretty good understanding of how color works on computers, however, trying to do something simple, like automating colour space conversion and file type has brought me back to the same old questions I had years and years ago, about what Apple’s colorsync technologies are actually doing.

Building an automator action offers me the ‘Apply ColorSync Profile to Images’ action.

Apply? Okay, what do Apple actually mean by this? Embed, Assign, Apply? So I look up the ColorSync Utility’s Help and I find this explanation under ‘Modify Image Colors':

When the file opens, click the leftmost pop-up menu at the bottom of the window, then choose an option.

Match to Profile: Changes the colors in an image to match the ColorSync profile. ColorSync Utility modifies the pixels in the image to match the new color model and ColorSync profile, then assigns the new ColorSync profile to it.

Assign Profile: Assigns the ColorSync profile for an image. ColorSync Utility does not modify the image saved in the file; it changes only the ColorSync profile for the image.

Apply Profile: ColorSync Utility modifies the pixels in the image to match the new color model and ColorSync profile, then assigns the image’s original ColorSync profile to it.

As you can see, the explanations of Match and Apply are almost identical, except Match appears to say the same thing twice. Perhaps it really, really, does it?

Assuming that Apple’s engineers know what they’re talking about, could someone please explain to me what the difference is between Match and Apply?

I ask this specifically, because the Automator action I mentioned earlier, specifically uses the word ‘Apply’. It also has a checkbox, which I’ve tried to google to no avail in the past and just tried again now. It says; ‘Preserve Original Color Space’. It seems that no one on the internet actually knows what this checkbox means. There is speculation, but nothing that I can find that clearly states what it does. What I’d really like to know, is whether or not I can use this Automator action to properly Match from the embedded profile, to a new one, for example, from AdobeRGB to sRGB.

Can anyone clarify these points for me?

Much thanks for any help,

Grant