Photoshop does not convert CMYK smart object colors color of master document.

[Taras_S.]

Photoshop does not convert CMYK smart object colors (with assigned ICC profile) to master object color with another ICC CMYK profile keeping appearance of colors. Instead it keeps values but destroys appearance. Conversion between different modes (RGB to CMYK, CMYK to RGB...) works fine - it keeps appearance, changing the color values. But CMYK to CMYK isn't working correctly. PS assigns profile, instead of converting. In the file attached you can see the same values when smart and master have different profiles assigned.

[NB, colourmanagement net]

@Taras_S. We need to know more please

Perhaps you mean that, in an image made up of smart objects and other layers, when you use Edit>Convert to profile - only the non smart objects are converted correctly and the smart objects get the new profile assigned but are not converted so now they look wrong? 

It's not entirely relevant to your question, but please be aware that its better to archive the layered document then flatten a copy before converting - say from RGB to CMYK. Converting CMYK to CMYK or CMYK to RGB is something we generally try to avoid. CMYK to CMYK really requires a color server to work right otherwise black only areas may end up as 4 color.

I hope this helps
neil barstow, colourmanagement net - adobe forum volunteer - co-author: 'getting colour right'
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[Taras_S.]

Not certainly in that way. I have a CMYK document. I add a new layer to it (for example, by dragging another CMYK file with "Alt" that creates linked smart-layer. Also it has the color profile different than that of the master document). What is the expected behavior of Photoshop under these conditions? I think it should convert the colors of the nested smart-object to the master object's color space in order to preserve the color. This always happens if the color mode of the smart-layer and the master file are different (eg LAB-RGB, RGB-CMYK, CMYK-LAB etc).

But in case of CMYK-CMYK there is no color conversion. Photoshop does not convert color to preserve appearance. Instead it just keeps values of the smart-layer distorting its color.

I illustrated this effect in the attached file. There is shown this unwanted PS behavior.

[Stephen_A_Marsh]

RGB and Lab are only 3 channel colour models. Combinations of the 3 channels can only make 1 discreet colour.

The 4th channel in CMYK makes all the difference, now the same colour can be made by multiple colour combinations.

Does one honour the channel values or the ICC profile "label" of what the values equate to?

The choice isn't so simple or universal.

[D Fosse]

I can confirm. This needs to be moved to "Bugs".

To demonstrate that this is not a gamut limitation (which was my first thought) - here's the same procedure run both ways:

(The original was first converted to a smart object, then converted to a different CMYK profile).

[Taras_S.]

How can I move it to the bugs?

[D Fosse]

A moderator needs to do that (I'm not). I was hoping someone would pick it up.

If nothing happens, repost in Bugs and link to this thread.