In the life of every artist or designer one day comes a time when they want to print something. You start reading what needs to be done, try to figure out how to prepare your files and, often, fail – why have the colours shifted so much? Why is the print so dark? Why did everything move like this?
If you’re looking for a short and comprehensive beginner’s guide on what you need to know to avoid the most common mistakes and problems, and some advice on where to look for more detailed info, search no longer and read this article – you’ll find everything you need below.
CMYK or RGB?
Each image you create digitally has its own colour space. If you’re planning on publishing your work only digitally, then RGB is perfect, but if you want to print, you need to start learning about CMYK.
Basically, CMYK is the colour space used for commercial printing, and to avoid a strange and ugly colour shift, you’re going to have to convert your file to it. How does it work, exactly?
CMYK creates colors by blending four colors of ink: Cyan, Magenta, Yellow, and blacK (also known as Key).
It is used to print in full color on items that reflect light but do not generate it, such as paper and fabric. – from printnija.com
There are several different ways to convert. The simplest one is, in Photoshop, to go into Image -> Mode -> CMYK. However, I do not recommend it – it usually gives pretty bad results. The better one, which will cause a much smoother transition, is to use Edit -> Convert to Profile.
Now, the menu that you’ll see may seem scary at first, but that’s because there are many different kinds of both RGB and CMYK spaces – many different colour profiles, but I’ll get to that in a moment. The basic thing to remember is to check whether you converted your image to CMYK before printing. At the same time, I’d advise against working in CMYK from the beginning – is simply has a much smaller colour range and you’re likely to get less saturated and vibrant colour than if you start working in RGB and THEN convert to CMYK.
Tip: If you want to see how your image would look in a different colour space without actually converting it, you can use View -> Proof Setup -> Working CMYK and check the View -> Proof Colors option below or just hit Ctrl/Cmd + Y.
Important: Like mentioned above, CMYK is the colour space used for commercial printing. So if you’re planning to print your work yourself at your home printer, it’s very likely that you don’t need to convert the colours, and that RGB will actually give you much better results. To get the best ones, you’re going to have to know the printer’s colour profile, which I explain below. RedRiverPaper has a pretty good and useful guide on how to use ICC profiles for inkjet printers (Canon, Epson, HP) while printing directly from Photoshop: http://bit.ly/2iqNxZA.
ICC Colour profiles
Profiles are simply look-up tables that describe the properties of a color space. They define the most saturated colors available in a color space; i.e. the bluest blue or deepest black your printer can produce. – from drycreekphoto.com
A profile is a small file that describes the characteristics of the device it corresponds to. For example, a printer profile describes all the color characteristics of the printer/paper/ink combination it was created from. (…)
The workflow, in basic terms, is to convert the colors of an image from the color space of the monitor to the color space of the output device. – from imaginginfo.com
I hope the above to quotes explained at least a little bit what colour profiles are to you, but don’t worry if you still feel a little lost – it’s a complicated subject. The basic thing you need to know is that if you don’t have a colour profile of the printer that’s going to be used to print your artwork, there’s a big chance that the colours are going to be different from what you see on your computer screen.
If you’re printing your work independently, it’s best to send an e-mail to your printers and ask them to send you the profile, or look at their website – it’s possible they have a pre-press section from which you can download the file. If you’re printing through some sort of a bigger platform, like DeviantART or Curioos, Inprint etc., look on the web – you never know what you can find, but in general, there are several profiles that are pretty standard in the industry and should give good results:
- For US/North American printing: US Web Coated (SWOP) v2.
- For Europe: Coated FOGRA 27 or 39.
I never had problems using the above, but like I wrote earlier, if you have the possibility to ask the printer directly, do it.
If you want to read a longer and more in-depth explanation on what the colour profiles actually are, check out this article on the PermaJet Photography Blog: http://bit.ly/2AipjVJ.
Another term you’re likely to come across is DPI or PPI. Now, what’s that?
DPI: Dot’s per inch. The number of dots in a printed inch. The more dot’s the higher the quality of the print (more sharpness and detail).
PPI: Pixels per inch. Most commonly used to describe the pixel density of a screen (computer monitor, smartphone, etc…) but can also refer to the pixel density of a digital image.
Resolution: Resolution is the measure of pixels in the display, usually expressed in measurements of width x height. For example a monitor that is 1920 x 1080 is 1920 pixels across and 1080 pixels down. – from vsellis.com
For printing, the standard DPI value is 300 (sometimes higher), and for web – 72. When it comes to resolution and printing – the bigger the better. You can have an image that is too small, but if you’re printing artwork, you probably can’t have an image that’s too big.
How to check your DPI in Photoshop? Go to Edit -> Image Size or simply press Alt -> Ctrl/Cmd -> I.
These are the basics, but if you want to know a bit more, read here: http://bit.ly/2Bz6HkG.
One of the first thriller covers that I worked on was “Echo’s Shadow” by Trace Noir. The cover was quite dark, me – still a bit inexperienced, and so I received an e-mail from the author that the proof came back much darker than intented and can I please do something about it.
I started googling, and it quickly turned out that there’s quite a few people with the same problem, but it took me a while to actually find a working solution. And here’s where ink density comes in.
Total Ink Density, or TIC, as you’re also likely to see it mentioned, is, as the name suggests, the total amount of ink in one area. Each of the letters of CMYK (Cyan, Magenta, Yellow, blacK) has its own numerical percentage value – for example, if the background of your piece is made up of 100C 80M 80Y 100K, the total ink density would be 360% for the background.
Now, too much ink in one place causes problems, especially if we’re talking about black – the colour spills to surrounding areas, often making them a lot darker than they are intended to be. The trick is to make sure that the Total Ink Density in your image doesn’t exceed 240%.
How to check it?
Firstly, make sure you converted your image to CMYK. Then make sure you have the Info Panel turned on. If you don’t, then go to Window -> Info or press F8. Then, use the Eyedropper Tool (I) and hover over the darker parts of your artwork. The right side of the Info Panel should show you the CMYK value percentages. If, combined, they exceed 240%, you’re in trouble.
How to fix it?
The best way I found so far is to use the Selective Colors adjustment layer (Layer -> New Adjustment Layer -> Selective Color). By using it, you can adjust every color separately, inlcuding black or white, which means that you can easily manipulate the CMYK percentages while making sure that your colours remain looking like the should.
Bleed and printers’ marks
Bleeds allow you to run artwork to the edge of a page. On a press, the artwork is printed on a large sheet of paper and then trimmed down to size. If you do not allow for a 1/8 of an inch bleed, any misalignment while cutting will result with the artwork not running to the edge of the paper. Bleeds ensure you get the results you need. – from serviceprinters.com
The basic amount of bleed most places ask for is 1/8 inch or 3 mms. If you do not include bleed, you may end up with uneven white space on the edges of the image. Still, different places will often require different bleed amount, so it’s always best to ask your printer directly if you’re printing independently. If you’re printing through a bigger platform, like DeviantArt or Curioos, you will notice that they don’t usually offer full bleed prints, which is why adding bleed is most often not necessary.
Bleed is a part of a wider category called printers’ marks, and there are other elements that some places might ask you to include in your file, but that’s relatively rare. Here’s some more info if you’d like to read up just in case, though: http://bit.ly/2zyFz3J.
The best formats for printing will be always predominantly PDF or in some cases TIFF. You can include layers in both of them if you need it.
Want to know more?
The best and most comprehensive resource on printing I’ve found on the net so far is Print Ninja’s Printing Academy: http://bit.ly/2j1T9qg. I wholeheartedly recommend reading everything they have if you want to deepen your knowledge – I use it often myself.