Oktober 10th, 2011 von buergermeister
Today I had a little conversation with somebody about colors. He didnt understand what I meant with an color profile, he simple said to me we cant change anything because pantone is proprietary. The whole thing isnt easy to explain, I think I should begin really on the start. And the start is the difference between the color model RGB and CMYK. I think most have heard of it and know simple how it works.
RGB is an additive color model in which red, green, and blue light is added together in various ways to reproduce a broad array of colors. The opposite model CMYK works as a subtractive color model. But there is another difference, you can create different colors with the different systems. So I made a drawing and hopefully it brings more light to the problem. (Yes I know its not accademically correct).
Yellow is the border for a CMYK color model and the blue one for an RGB model, here sRGB. So you can see there is a difference between the colors you can reach with RGB and CMYK, thats one of the problems. Technically I can create pictures on my computer they cant printed. But you should also see, there are lot of colors they cant be printed with the CMYK model. And thats where Pantone comes in, they begun in the 1950ies to define a color palette called Pantone Matching System. Most of the colors was outside of what you can print with an normal CMYK model, so that colors was unique. One thing is sure when you like to establish a brand, you will like unique colors. Starbucks e.g use Pantone 3425 C for there trademark. Pantone even created colors for some trademarks like that choclate who comes from a lilac cow . There are some competitive systems like HKS or for germans more known should be RAL. Yes the person, has right its intellectual property of Pantone so you cant find it in Inkscape or GIMP and you dont need it often. Such spot colors are mostly printed in a second process, means first will be all process colors printed and then a process print that spot color. So you dont have to give the printing company a file where is the spot color attached to. Mostly its only one color so you can give them another file where the spot color is extra, and that have to be only a black and white graphic. But remember in the other file must the place then be white, because printing on an other color changes the results. And then say to them which spot color should be the black. Best way speak with the printing company, how to do it.
So what are now color profiles? First of all not only humans see colors different even hour devices do that. The individuality of a device is reflected or should be in his color profile. There is an standard for them created from ICC as ISO 15076. So when we talk about printing, we talk about digital printing today. So its an device and it should have an color profile Of course is has
Such an color profile can be transferred/translated into another one, thats why you havent to give a printing company not really an CMYK PDF today. Normally you can give them a PDF with an embedded profile. There are some organizations they established some kind of standards. For europeans is more ECI interesting (ECI-Coatedv2.icc would be a common profile), in US there is a thing called SWOP more common an example would be USWebCoatedSWOP.icc
But why its not unimportant to know the target profile before? You remember the differences between RGB amd CMYK and the colors they can created with. There are also differences between some profiles. So to make sure that everything I draw can be printed, I can use the target profile in Inkscape (GIMP cant do that but his little brother CinePaint can) so colors they out of range will be marked in a special color. And really cool it is, when I use color managment and I can see the colors from the target device And there is another point, with every translation there comes little deviations. So the best way is to have no translations between color profiles