[quote user="Phil1923"]QUOTE 1: "As far I know, nobody will start a job for 10 or 20 proofs, even 50 proofs." Phil: The advertising agency for Macy's chain of stores will insist on it. Millions of dollars are at stake.[/quote] Maybe this compnay want to do it, but this is not how the world works. A Heidelberg average speed is around 10.000 copies/hour, that means that 10 "proofs" will take a few seconds, after a big job for preparing the machine and paper. That could be important if you will print 2 millions flyers, but this is not a solution for all jobs. [quote user="Phil1923"]QUOTE 2: "Color reproduction should be perfect always, for all jobs." Phil: The only time that color reproduction has to be "perfect" is: 1. An original is present to which the print can be compared. 2. The client is a PITA. Besides, you are confusing "accuracy" with the perception of color. For instance: Consider a white tablecloth next to a window. 1. Before sunrise, it's a bluish gray. 2. At sunrise, it's orange. 3. At noon, it's blue. 4. At sunset, it's red. 5. In tungsten light, it's the color temperature of the light bulb. 6. In candlelight it's yellow. If your print shows those colors "accurately", it will look ridiculous. [/quote] Yes. colors SHOULD be accurately, of course under the same conditions . Same paper, same light, etc.Imagine that you create a flyer, and you use 50% black as background and the logo use an special "blue" (such as C:100 M:60 Y:0 K:0) and "orange" (such as C: M:50 Y100 K:0). All it's OK, and the next month your client want to print more flyers, same design,. same paper, same colors, only changes prices. This second print should be the same colors than the previous one. Not "violet and yellow" nor "cyan and red". If you compare the second edition with the first edition, if both uses the same values, both should be identical. That was what I mean as "perfection". Unfortunately, that not always happens. Sometimes, the first printing are darker and the latest are lighter. or start right but the latest printings are yellowish... this is a printing issue, of course, but all printings should be the same tone. And, if you compare with the reference proof, it should match. Printers can't compare each job at the sunset or sunrise, but they will compare both under the same light conditions. Most companies uses "neutral" lights, by combine red light lamps (bulbs) with fluorescent lamp or tubes, and use an spectrodensitometer to capture the printed result. And yes, the values of the Color Proof should match with the printed values. Most of the printing machines receives the information directly from the RIP, then adjust it automatically. Of course, not all companies around the world have the same quality, and not all takes care about the printed result, but this is how it should be, and it's how works almost all printing companies around the world. If you use 50% black, it should be 50%, with a small tolerance of 1% or 2%. The CTP and the RIP should be calibrated frequently to maintain the right values, including dot gain (due, for example, to the pressure over the paper), and it should be also according the paper. Yes, some companies doesn't care about color profiles. They just print what receives. But if you want a high quality output, and want to output the right colors, all steps will be important
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