change RGB to CMYK

[Dominique Perchet]

Unable to convert RGB files to CMYK process despite multiple attempts. Each time, the file comes back in RGB.

This is a new problem So far, everything was fine. What?

[walt.farrell]

What exactly have you tried to do? Which application are you using (and what release of the application)?

[Dominique Perchet]

2 steps

1 - configuration : cmjn 

then, 1 close the file

then I open and I retrieve my file in RVB (second picture)

 

[lacerto]

You cannot technically save an opened .PNG image as a CMYK file (even if Affinity app will seemingly allow saving a CMYK .PNG file "back" with existing file name). When you close and reopen the file, it will still be in RGB color mode (but at least the colors are not messed up, as they used to be at some point). [So, after conversion, export the image to a file format that supports CMYK, like JPG or TIFF.]

[Alfred]

Just now, lacerto said:

You cannot technically save an opened .PNG image as a CMYK file (even if Affinity app will seemingly allow saving a CMYK .PNG file "back" with existing file name). When you close and reopen the file, it will still be in RGB color mode (but at least the colors are not messed up, as they used to be at some point).

It really would be better if the app refused to allow an operation which is incompatible with the chosen file format. I haven’t checked whether a warning is triggered by an attempt to save a JPEG as CMYK when the existing file is RGB (or vice versa) but if not it should be!

[Alfred]

57 minutes ago, Dominique Perchet said:

2 steps

1 - configuration : cmjn 

then, 1 close the file

then I open and I retrieve my file in RVB (second picture)

If you need to save to a lossless format (which I presume is why you aren’t using JPEG) then you could use TIFF instead.

[lacerto]

7 minutes ago, Alfred said:

It really would be better if the app refused to allow an operation which is incompatible with the chosen file format. I haven’t checked whether a warning is triggered by an attempt to save a JPEG as CMYK when the existing file is RGB (or vice versa) but if not it should be!

Yes, I agree. But I am not sure about the parallel case with a JPG file (when saving back keeps the CMYK format because it is technically possible). If saving back without confirming an overwrite is supported in the first place, what kinds of operations would be radical enough to require a user confirmation -- switching the color mode IS a big change so at least it is a good candidate; but there are limitless ways to completely change an existing image and it would be difficult to decide a reasonable trigger for a warning.

[Alfred]

42 minutes ago, lacerto said:

Yes, I agree. But I am not sure about the parallel case with a JPG file (when saving back keeps the CMYK format because it is technically possible). If saving back without confirming an overwrite is supported in the first place, what kinds of operations would be radical enough to require a user confirmation -- switching the color mode IS a big change so at least it is a good candidate; but there are limitless ways to completely change an existing image and it would be difficult to decide a reasonable trigger for a warning.

A good point well made, as they say!

[Dominique Perchet]

I solved my problem using the following process: save as... in affinity photo format: then, the CMYK format is preserved Phew!

merci pour votre intérêt porté à ma question...