icc color profile (keep embedded profiles) ???

[.: NICKY G. :.]

Unless I have missed something, I believe that Affinity has a GREAT lack of color management, which should not be underestimated (I have tried years to understand this thing about color management in Adobe, I wouldn't want AD to be missing).

In practice I make the example with the Fogra39.icc profile applied to the default document:

If I wanted to insert an image with an embedded profile that differs from that of standard use in AD (fogra39) documents, AD creates a conversion of numeric values for me!

Eg I have an image file prova.jpg with Fogra27 color profile.
This photo is a gray rectangle k 30% and one k = 100%.
If I insert this image into an AD document with fogra39 color profile, my chromatic values are converted and I will have a
k30% = 25% -19% -19% -2%
k100% = 77-73-58-82
so I have a color change and it changes the numbers applied to the image.
IT MUST NOT BE SO!

in Adobe (as in the photo), there is the option to preserve the color profile of the inserted image and treat only the numeric values.
so 30% in fogra27, 30% still remains in fogra39.
(in jargon this is called: honors the assigned profile, preserving the numerical values)

Actually this thing works well for images that have no color profile assigned, but generally the images always have an assigned profile!

This thing of the color profiles managed in this way by AD is a serious problem.

In Adobe, I can insert images in any color profile, then I do the conversion in PDF export, assigning the Output color profile, but always preserving the numeric values, never converting into a profile, because doing so will bust all the color values , so if I have to have a 100% black risk I will be converted into a four-color black with colors coated on all 4 CMYK channels. The same goes for the RGB.

I think this thing should be well studied by Affinity developers looking at how the competition has moved. You risk that when I go to print by changing the color percentages, I can also have changes in the finished print result. !!!

[v_kyr]

See this thread which discusses related things to this theme.
 

[.: NICKY G. :.]

4 minutes ago, v_kyr said:

See this thread which discusses related things to this theme.
 

I will read it calmly.
But taking a quick look I don't think it's the solution to my problem. (I hope I'm wrong though)

[firstdefence]

If you have a different profile in the file opened in Affinity Photo it should not convert it unless the settings in Pref > Colour are set to do so.

[.: NICKY G. :.]

Exactly as you say, but an icc color profile different from the color profile in use in the document, it always comes, in any case converted from a source profile to a destination profile, instead the exact procedure is that it must always keep the numeric values and never convert to destination (unless appropriate user requests).

In practice, with "no profile embedded" images it behaves well in this way.

Now that I remember well "the Adobe theory" there are 3 criteria of choice in color management in Adobe Suite.
1. deactivated
2. maintains the embedded profiles
3. converts into a work profile

the right choice is 2, it keeps the numerical values embedded in the color profile of the file. Put simply, consider that photo as if it had no color profile applied and read only the numerical values applied to it.

Then in the PDF / jpg export phase etc, you decide to "keep the numerical values" and apply a color profile of your choice, which can be either the work document or other.

Practically if I have a fogra39 profile document and I insert images with the fogra39 profile embedded, the numerical values are read in the right way. If I change color profile to the working document and I put fogra27 example and I click Assign, the color profile in fogra27 will change and the numerical values will remain the same as before (and it works well), but if I then have a fogra27 document and insert an image again with different profile eg fogra39, this image will be converted and numeric values will change.

In practice, when inserting a photo AD always applies a color conversion in the destination profile !!!! Even if the Convert colors box is not checked in the color preferences.

I don't think the color assignment command works well.
The color profile of the document should be ASSIGNED to each image inserted, imported, linked to the document so as not to VARY the numerical values even if you work with different embedded color profiles.

CAUTION!!!
Working appropriately with color management in the press, web, etc. (but above all in the press) is FUNDAMENTAL!
Incorrect conversion of numerical values can lead to serious financial damage during printing!
A trivial example if a 100% black is converted to a rich black 80-80-30-80 is not the same thing!
Not to mention color change in images or dominant etc ..

this thing is very delicate Attention Affinity !!!

 

It took me years of study to understand how the "good" thing works in Adobe, now here I find myself headed and above all with the awareness of a wrong management by the software.

Affinity we would love to leave Illustrator (because it's shit!) But you have to be able to do it without problems!

 

[R C-R]

1 hour ago, .: NICKY G. :. said:

Exactly as you say, but an icc color profile different from the color profile in use in the document, it always comes, in any case converted from a source profile to a destination profile, instead the exact procedure is that it must always keep the numeric values and never convert to destination (unless appropriate user requests).

Both the source & destination profiles are device dependent. The document just contains a set of numeric values that do not by themselves characterize how colors will be represented by any destination device (printer, monitor display screen, whatever). Color management typically involves a translation from the input space to a standardized Profile Connection Space (PCS) using a Color Management Module (CMM) & another CMM to translate to the output device.

The well regarded three part Cambridge in Colour article on color management explains how this process works much better than I can, so maybe check it out....