Sam Moxon writes: >> My original request for assistance was based on not being able to produce an acceptable on screen conversion in PS6 of certain saturated colours, we are in fact printing what we see on screen. So the problem is presumably with the initial conversion rather than its interpretation by the iProof. I present my work to existing and potential clients as commercial CMYK outputs, or as a simulation of such, rather than art prints and opted for this system as a method of producing images that best displayed my work in that environment. On a whole it has been a success until now. <<
Sam, Attempting to play catch-up on your previous posts...so you have a wider gamut device which is being gamut limited to produce a press simulation. Fine. Why do you say it is not a success? It would not be a success if your aim prints showed 'powerpointblue 255b' as a rich colour. Showing a poor conversion of the out of gamut colour is right. Then you have to ask are there other conversion methods, profiles or post separation edits which can overcome the poor conversion - by making departures which may be more pleasing than the base conversion. Sure the new hue is just as incorrect as the poor conversion, but it now looks better (pretend you never saw the original). As the required hue is out of gamut - one can't be too picky on matching the original. But that is not to say that one has to accept a default mode change. If you are happy that the process is showing you a true representation of the final output (like the colour from a press) - then it would seem to be a simple matter of finding out what mix of CMYK inks gives saturated colours for the hues that concern you. Obviously blues are a problem, with greens and reds having issues too (but not as much as rich saturated blue). Can you supply any LAB values for the colours that are having issues on conversion? How about a link or an offlist post of a low res crop of the section in question? I have some links to colour swatches if you would like to get a feel for the broad range of CMYK press colours possible from your device, which you can use hand in hand with your softproofing: http://www.members.ozemail.com.au/~binaryfx/CMYK_Charts.pdf.zip http://www.realtimeproof.com/download/download_colorbooks.asp http://www.fho-emden.de/~hoffmann/swatch22112002.pdf I would also suggest you look into CMYK and GCR theory - so that you know what makes a hue pure or impure - which will make corrections easier. For many folk the art and skill of prepress has been reduced to a mode conversion command or a profile. As you have found, there is no such thing as a perfect conversion for an out of gamut colour - which is where knowledge and experience come in. At the end of the day, one has to accept that reflective CMYK is going to be somewhat disappointing when compared to the RGB capture that spawned the CMYK and even more so for known problem hues in four colour process printing (with or without post separation edits to 'improve' things). It is then a matter of making appropriate decisions to maximize what you have in the final limited output space. Is this a suitable time to introduce 'imaging services by Stephen Marsh'? Sincerely, Stephen Marsh. =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
