On Sep 15, 2010, at 9:29 AM, John Culleton wrote:
The physical printing press will either use spot colors or the process colors of CMYK. That is the target. That is how modern printing presses work. They mix those four colors and not Red Green and Blue. So I suggest:
Well, not really. There is a fair bit more than four colors going on, *especially* if any spot (e.g. Pantone) colors come into play. In fact, the classic Pantone use *precludes* four-color press output.
However, the main point to take is that there is no such thing as "the" process colors of CMYK. CMYK is a very fuzzy term that describes a *type* of colorspace. Keep in mind that there is no such thing as "the CMYK colorspace".
- Use CMYK from the beginning to develop a print document. This gets
around the smaller gamut problem.
Very close. One should probably use a *specific* CMYK from the beginning. SWOP is one of the more common ones in the US (but depending on the use, others might be preferred such as SNAP). Most of Europe uses a *different* 'generic' CMYK color set that some call 'Europe ISO Coated FOGRA27'
Using the right CMYK colorspace for the right application in the right country is important.
- For exact colors don't depend on a monitor representation,
calibrated or no. Take the CMYK values and look them up on e.g. Galaxy Color Gauge Color Pro. This still won't be "exact exact" but it will be the closest you can get without having the printer produce a proof copy.
But *if* you provide values in a standard CMYK colorspace, *and* the print house follows good practices you will get very very close. You provide things in a specified industry standard CMYK colorspace and then the print house takes on the burden of making their printers with their inks combined with things such as the current shop temperature and humidity and end up with a nice print.
As my father used say, don't fight the problem. Printing presses use process colors AKA CMYK. Work backwards from that.
*Some* presses do. Often you get plates run with spot colors, some with hex (aka six) colors, etc.
The software products Photoshop, Scribus, Krita, InDesign, TeX, Open Office etc. all can work in and produce a pdf file with CMYK generated colors. So they solve the problem insofar as it can be solved. Inkscape needs to be added to that group IMO.
We need to tighten up our CMYK support a bit. Inkscape SVG files can be produced that are fully compliant with all pertinent specs, but most ways of getting things to the print shop end up doing lossy conversions. PDF is the main target of modern printing, though.