Composite CMYK + Spot vs AsIs

[irreality]

Well.... I know there has been alot of talk about what the difference actually is.

and today I encountered one of the differences.....

When outputting with Composite CMYK + Spot, to PS it is removing some of my screened colour. (gasp) most noticably in the black channel.

anyways.

When outputting the same file with the AsIs option in Quark. well - I get just that effect... as is... the colour does not drop off.

Does anyone have an exact answer as to why CMYK + spot prints differently than AsIs (other than the fact they are different Options) ?

I am really interested to find out why this occurs.

Thanks

 

[Glenn McDowall]

Composite CMYK + Spot is under the hood DeviceN.
Quark tries to move stuff to a DeviceN space and some preflights see cmyk stuff as Spot colours. Also Quark's Color management settings come into play, if you ask for cmyk to be managed to cmyk it will be, RGB will be converted to cmyk.

As Is leaves RGB and CMYK as RGB and CMYK and you get the choice of whether to bundle in postscript colour mangement based on ICC profiles (I don't see anyone using this).

its difficult to see what is going on because there seem to be a lot of file types that just don't behave as expected, particularly duotone EPS files from photoshop, (there is even differences in colour between Jaws and Distiller) in either workflow.

personally I stick with As Is with Quark7 and 8, and DeviceN with Quark6. (As Is with v6 used to give rgb trim marks)