New to CMYK conversion -vague understanding of some theory

[tmx3]

Hi,

I don't have a printer at present but am interested in conversion as an issue for photographers, and in general. I'm also interested in the limits of photoshop (if there are limits) in dealing with conversion -not sure if anyone can recommend a book specifically on the issue??
I was recently looking at a magazine's website where they supplied a custom profile for contributors to convert their images to. They also specified, in terms of under color removal, no more than 330% total density.

How would you specify this (both ucr +image density) in photoshop?
What program do you need to create a .icc file?
Say you want to add more magenta, black whatever to a image when converting - what is the best method? Curves? Selective Color? Could you use channel opacity to reduce a color within the ratio?  

I'm also aware banding in grads is something photographers have to keep an eye out for,  as with certain colors potentially "muddying" on conversion - what other issues might a photographer bear in mind , and could anyone explain technicaly why certain colors go muddy - obviously in general I'd assume an issue with extent of gamut - but what specifically?

sorry for the plethora of questions, i'm just really keen to begin getting my head round this(!)
Thanks in advance for your responses!

[Nick Rains]

Hi,

I don't have a printer at present but am interested in conversion as an issue for photographers, and in general. I'm also interested in the limits of photoshop (if there are limits) in dealing with conversion -not sure if anyone can recommend a book specifically on the issue??
I was recently looking at a magazine's website where they supplied a custom profile for contributors to convert their images to. They also specified, in terms of under color removal, no more than 330% total density.

How would you specify this (both ucr +image density) in photoshop?
What program do you need to create a .icc file?
Say you want to add more magenta, black whatever to a image when converting - what is the best method? Curves? Selective Color? Could you use channel opacity to reduce a color within the ratio?  

I'm also aware banding in grads is something photographers have to keep an eye out for,  as with certain colors potentially "muddying" on conversion - what other issues might a photographer bear in mind , and could anyone explain technicaly why certain colors go muddy - obviously in general I'd assume an issue with extent of gamut - but what specifically?

sorry for the plethora of questions, i'm just really keen to begin getting my head round this(!)
Thanks in advance for your responses!

Use the printer-supplied profile to soft-proof in PS, that will give you a good idea of how your colours will behave.  You can edit using this profile as a working space too, then you cannot alter the colours past what can be printed. Do a search for Soft Proof and you should find what you need. I work in RGB until the last moment; if you want to work in CMYK (!) then Dan Margulis has some good books on the subject.

Also, if the printer supplies a profile, that should be all you need - the UCR, max ink stuff was for older style seps settings and not be needed.