there is nothing wrong with a layered CMYK file as long as its made correctly.
I keep my files RGB this way I can convert to the correct CMYK that is needed.
I’ve never had problems placing transparent files with dropshadows.
I did a quick trial-run (soft-edged ECI-rgb object in front of ECI-rgb-background in an Indesign-document versus both objects separated as ISO coated in Indesign-document) and had worse banding in the pdf 1.3 from the rgb-version.
It sure would be nice if the montage could be done all in Photoshop but workflowwise doing it in CMYK just might be the only convenient way depending on the number of variations.
I guess soft edges should work out OK, but if Your rgb-files combine layers with different blending modes or adjustment-layers that are supposed to affect the background it will not work out.
If You do the shadow as Solid Color-layers with the maximun allowable 4C-black (according to the specific print-process) You could actually add noise to the mask (masking out the 100% black parts of it).
"Banding is a big issue in a creating a layered CMYK drop shadow w/o a background (checkerboard transparency), as I can’t add noise."
Banding isnt a result of CMYK color space.
Banding is a result of poor linearization characteristics of the output device. Be that in print or monitors, banding can occur with less than stellar print devices/processes or the wrong monitor settings.
The limits of 8bit color channels doesnt help this, but there are numerous other factors involved.
I have a client that is requesting layered files from me (products w/soft drop shadows), so they can insert/scale/change their own CMYK backgrounds in Indesign.
Another thing to consider: When the client scales the product shot, they’ll also be scaling the drop shadow. This is okay, but 2 files with widely differnt scale percentages that appear side-by-side in a layout might look odd.
If the client is skilled and only simple drop shadows are needed, perhaps InDesign’s own drop shadow functions would suffice?
make your shadows using layer masks on a layer that is filled with the desired drop shadow color, this allows you to add noise to the layer mask and in some cases to the actual layer as well…
