Color mode - don't understand

[jw2004]

When document is "Document mode", and if there are more than one layer, the channels is always RGB mode, can't switch to other mode like CMYK, Lab mode and so on, even all the layers are CMYK mode. this make something trouble, for example, I can't extract the M channel to layer.

why not determine the color channels by the bottom layer?

2015-04-10_14h59_31.png

two layers are CMYK mode, but channels is RGB mode,
when there only one layer, the channels mode is the same as layer's channel mode.

[Gerhard Huber]

Have a look on the manual
2.10 Document Mode And Picture Mode
to understand how it works.

Gerhard

[jw2004]

Below is my test result:

2015-04-10_15h52_14.png

[Gerhard Huber]

sorry, but the only help for versin 18.5 seams to be uncomplete here, so here a part of the version 19 manual:
In pictue mode the background layer defines the color space, in document mode the color space is defined by the ICC color profile of the document

Gerhard

[bkh]

two layers are CMYK mode, but channels is RGB mode,
when there only one layer, the channels mode is the same as layer's channel mode.

This may seem strange, indeed. The channel display depends on the colour working space which PL uses, and that seems to change when you add more layers (I don't think that there is an explicit rule). Probably, the cleanest solution is to assign a CMYK profile to the document (either while creating the document or in the document attributes panel), and PL will use that colour space as the working colour space.

Cheers

Burkhard.