Let’s start simple!
When I start creating a printout, I create a file in the page make-up program set to the exact dimensions I want my printout to have. The bleed edges (the extra space we let out for trimming machines) is added afterwards and lets the background bleed outside the file edges.
Before I start creating files, my computer must have the proper colour setups.
Pictures are a vital part of every printout. They can help it or ruin it if they’re not right. When we speak of offset printing, we’re talking about 4-colour printing.
And here comes the great issue of colour management. Photoshop is a very good program with many possibilities, one of which is colour management. However, you must know when and how to use it. For example, if you want to print on an US cylinder printing press with coated paper (like velvet or illustration), you’ll have to use the web coated profile provided by the program. Colour management is not that simple, though.
The colour output is one of the most important features of a printout. Pictures must be edited to look lively. But most of all they must carry the correct profile. ISO has created 4 special profiles, which are the ones we should use. If you want to install them you can find them in the website of the company where I work (www.lyhnia.com), on the tab “χρήσιμα” (=useful). If you need any further information, please don’t hesitate to call me during office hours on the number you can see on the website (internal number 105).
What I would like to stress out again is the importance of using the right profile for each project. For example, if you want to create a printout to be printed on coated paper (like velvet or illustration), which is the most common printing type, you should use the ISO Coated v2 (ECI) profile. If the file you’re working on is going to be printed on uncoated paper (offset), then you’ll have to use the ISO Uncoated profile. If you want to print on a cylinder press, you’ll use the ISO Web Coated and if you want to print on newsprint paper, you’ll use the ISO Newspaper profile.
Let’s be a little more specific! The offset paper has pores that absorb the ink and make it look blurred. The ISO Uncoated profile kind of removes some of the total ink quantity used, so that there will be less absorption-generated colour loss. The rest of the profiles work in about the same way.
When we have an RGB photograph, directly from a camera or a stock, the colour information is extremely broad. When we convert the pictures in CMYK, we narrow the colour range. The RGB is light, a much wider spectrum than the CMYK, which is ink. Many colours on the light spectrum cannot be rendered with 4-colour printing. For example, fluo orange and green look very shiny on an RGB picture. Each colour profile we convert a picture into is for a different use. So if we convert the picture in the web coated profile (cylinder machine), we’re actually narrowing the colour range more than if we convert it in ISO coated.
Nowadays, many printing companies have proofing programs that check the PDF files and if needed convert the pictures into the right profile. But why leave our pictures’ fate to programs? Isn’t it better to know exactly what we’re going to print? Sometimes, even programs make mistakes.
I tried to explain everything in the simplest way possible and I hope I haven’t bored you too much…
I also hope you’ve realized how important it is to adjust the colours correctly.
Your news and questions are always welcome.
The blog will be open for solving problems and also for you to post solutions you may have found.
See you soon.