Hi Matthew,
Belt and braces for CMYK file supply.
First step is dialogue if at all possible. Agency or design group production types are the first port of call. If they are reluctant to talk whinge constructively to the art director about what a shame it would be if somebody messed up his/her masterpiece , and get him/her to find the right people to talk to.
Once you've reached the production person, hope and pray they have a grasp of the situation. If it's obvious that they don't , suggest that they are probably far too busy to deal with the job and suggest a direct call to the prepress house/ printer.
Experience suggests that it's probable that one of the following responses will be forthcoming:-
a)"would you like us to send you a copy of our RGB/CMYK ICC conversion profile " (!)
b)"we are fully colour managed and will deal with your tagged RGB file responsibly " (!!)
c) These are our dot gain curves / ink limits and black generation requirements etc" ( !!! )
d)' just convert your RGB to CMYK in Photoshop V4 like we do "
e) Send us ordinary CMYK . The CMYK description is 300 dpi.
f) I haven't the slightest idea what you are talking about , and neither does anybody else here"
From your mail it would seem that the response you got was near the lower end of the above.
So where to from here. Well the first step is to let the prepress house / printer know that you know what you are talking about and that you'll be talking to the client about your conversation ( in a friendly and co-operative manner of course).
Then prepare for most eventualities .For CMYK file supply, if you have an idea as to where your work is to be printed , it will give you a head start .
If it is for magazines and high run catalogues on a coated stock , look to the ISO webcoated profile on the ECI site ( ISO coated will give you a maximum ink percentage of 350% ....generaly too high for this kind of work ) . If it is for higher qualiity / sheetfed work then the equivalent profiles can be found on the ECI site also. Be extremely wary of exceeding ink limits on any subsequent CMYK editing after RGB conversions.
Slightly more confusing is how you supply aim print / validation prints to suit .It is possible to get a fairly close simulation of the above colourspaces by cross rendering your final output files to a suitable inkjet hat has been properly calibrated/ profiled.
It' better still of course to have a suitable inkjet running through a RIP that can certify your output with the appropriate software and instrumentation. Just don't call the output a "contract proof" unless you are contractually bulletproof, insanely wealthy or have a reckless regard towards bankruptcy.
If you are supplying RGB , I would go so far as to say never supply Adobe RGB unless it is specifically requested . sRGB ( s****yRGB call it what you will ) is safer when venturing into the unknown and possibly darkside of reproduction. Indeed , some will argue that for certain types of imagery/ conversion it is a better RGB origination space.
But even if you are supplying RGB , I would suggest that you supply an / aim/validation print that is restricted to the CMYK gamut of your destination printing space , be it generic or specific , and make this clear on the "read me" that is supplied with the image.
Which of course means that you must send a "read me" file with the image. Even if it is never read , it will be the best basis for any necessary disclaimers that may follow.
Most of this information is in the DIG Code of Practice for digital image file supply ( we published it back in 2000) and available from the AOP website FOC, The' read me 'should contain all the elements as specified in this code). All of it will ( should?) be available on the forthcoming PPA and IQA best practice guides that we are working on now.
Of course , all of the above should be backed up by a comprehensive knowledge by the supplier and receiver of the part of the workflow that one is involved in , as experience and understanding cannot be replaced with documentation and rigid rules in a working environment. This is why we passionately believe that there should be adequate provision and take up of transparent and non- proprietary training for the 'new' ( ha! ) technology for all parts of the industry from image capture through to press.
Better stop before me soap box disintegrates.
Regards,
Bob Marchant.
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