What is a device-N image? I've heard/read that term before.
Device-N helps remove some of the constraints of specifying composite artwork for print to merely CMYK. Traditionally there were Greyscale, RGB and CMYK images. Considering that RGB isn't for print and Greyscale just does what it says on the tin, Device-N images can be defined using any process and/or spot ink. So, for example, if your company logo is constructed from process black and spot orange, you could export your logo as a single Black + Pantone [X] device-N image.
This has been possible for many years with the likes of Photoshop where images could be exported as TIFFs (or native PS files) with CMYK + Spot channels. It may be that there are multiple spot channels and each CMYK channel is empty, but the end result ise the same.
Beforehand, one popular method was to use DCS EPS files to go beyond CMYK. But these are a complete pain to handle and process; for example, it is impossible to embed a DCS EPS file into Illustrator. Sadly, it remains the rock-bed of many workflows - but hopefully it will be replaced by much more manageable device-N solutions.
(Oh - and I am donning my hard hat as I know the DCS EPS topic can cause a lot of aggravation ;-)
The only advantage that comes to mind with spot colours and images in ps, is the ability to use the built-in trapping that ps has.
Trapping raster artwork is soooooo much easier than attempting to maintain vector artwork whilst trapping. I personally feel the best place for trapping is at the RIP stage; once the huge images have been generated that eventually form the basis of the final output, it is here that trapping can be applied with least issues. IMHO.
But I realise that specialist trapping is required in some higher-end circumstances, hence the availability of specialist trapping tools.
Also, for flexo, a minimum and maximum dot can be controlled (easily).
Finger's crossed that it may be possible in Ai in the near future.
Best wishes,
Nick
