Hi Ros,
I've been using my own custom ICC profiles in C1 for art repro work for some years, and they're definitely more accurate for this purpose than the generic C1 profiles, which I assume are tuned for 'pleasing' results rather than pure colour accuracy. (The reasons for the modifications mentioned in the other thread are that some artist's pigments, blues in particular, don't always reproduce identically and frequently shift towards cyan.)
I use PM5 with the additional camera profiling module and a Digital SG target for the profiling. Unfortunately I suspect neither PM5 itself nor the camera module are now available since the takeover by X-Rite, unless you can find old stock* or a secondhand copy somewhere and, AFAIK, X-Rite doesn't offer anything equivalent. About the only good thing they've done is to ensure that the original dongle continues to work with both the old PM5 software and the i1Publish upgrade, so that I still have the benefit of both as required.
*Probably a bit of a long shot after all this time, but you could try Native Digital or Colour Confidence in the UK to see if they still have anything available.
The only other software I currently know of for camera ICC profiling is PictoColor's InCamera plug-in (
http://www.pictocolor.com/incamera.htm), though I've never used it. It also appears only to support 32-bit versions of Photoshop.
If it would be of any help, I'm happy to run a few profiles through PM5 for you, if you'd care to email me the target images - ideally with the larger DCC SG target if you have it, otherwise the standard 24-patch CC will be OK. You should be able to PM me via my profile, otherwise you can reach me via the contact page at
www.colourfasteditions.co.uk - probably best if you get in touch first so we can discuss file specs & profile requirements etc.
Best,
Malcolm