It is important to know that printers have eyes. Well… Sort of. Printers interpret data that is sent to them from an application or a device. That application or device outputs using a certain language, called a color space. The printer interprets the output, and then prints. So let’s say your Macbook Pro and CS4 are speaking Spanish, but your printer is speaking English. What basically happens: the printer listens, hears the Spanish, and tries its best to interpret it. Now, despite the fact that your printer may have taken AP Spanish in high school, it still doesn’t know every word in the dictionario.
Fortunately, it’s fairly easy to fix this problem. On the first opening screen in Photoshop and Illustrator, you have the choice of working in RGB or CMYK. Pick CMYK if your design will ever make it to the print world.
Photoshop settings for print design
A word about color spaces…
Without going much into detail, RGB refers to two different color gamuts (sRGB and Adobe RGB), both based on modeling light to produce colors. Red, green, and blue light can theoretically be added together to create any color of light, the “100%” mixture resulting in white. The natural “blank canvas” of RGB is black, or an absence of light.
On the other hand, CMYK is based on mixing four colors (cyan, magenta, yellow, and “key,” an old printing press term for black) to theoretically reproduce any color. The natural blank canvas for CMYK is paper.
Unfortunately, there are colors that cannot be reproduced in the gamut of CMYK that exist in the gamut of RGB, particularly brighter colors, especially in the cyan area. This is where we run into our problem. Simply put, RGB speaks better spanish than CMYK. There’s tons of literature on color management available online or in print. (Note: CMS, in the print world, stands for color management system.)
2. Forgetting to use Rich Black
If there is an unforgivable sin, this would be it. Again, a simple understanding of CMYK is needed.
A printer takes the CMYK info it is sent and puts out ink according to that info. CMYK value refers to a set of 4 numbers between one and 100 representing the amount of each color mixed in to achieve the desired color. So you would immediately guess that k=100 would mean black, right?
Larry said so.
K=100 produces a dark grey that is definitively not black.
Once again, easy fix; use values for rich black. Rich black mixes in some cyan, magenta, and/or yellow to darken the 100% Key. There are many different opinions on what is best, but there are basically two kinds; warm and cool. Generally accepted values (in order of CMY) are 70, 50, 30 (known as “designer black”), 60, 40, 40 (cool black) and 40, 60, 40, (warm black). All of these are mixed with k=100.
Some people say that a “C” value of 40 and a k value of 100 does the trick just fine; the point is to add some kind of extra into your blacks to make them… well, black.
Do NOT use rich black for smaller text; registration problems (where one cmyk ink prints slightly in the wrong place) will make your text unreadable. And no one wants that. Usually using k=100 for black text is readable enough.
Another neat trick: if your text is large enough that you want to use rich black, but is just small enough that registration may pose a threat, outline your text with .5 or 1 pt of k=100. This will take care of the registration problems. Note: the outline should be on the inside and should replace the original area it lays over, so that your text is not improperly displayed.
3. Using the wrong resolution
A low resolution will show pixelation both on screen and in print
Using the wrong resolution in your works can be detrimental to your final outcome. It is important to know the final destination of your work so that you can design at the correct resolution. Most printers print at about 300dpi (dots per inch), some even at 600dpi or above. The resolution of a monitor is 72ppi (pixels per inch), and is a default setting in Photoshop and Illustrator for RGB design.
A few things to note…
So let’s talk about some basic differences between dpi and ppi, and then decide what is best to use for different projects.
Simply put, pixels are square, dots are… well, dots. They consist of one color. Obviously, the more dots or pixels per inch, the more detailed and accurate your picture will be. It is important to design at 300ppi so that when you print on a 300 dpi printer, each pixel is translated as a dot. It is okay to design at a higher ppi than your printer’s dpi, but be careful designing below 300ppi.
Unless you are designing something huge, the magic number for print design is… you guessed it, 300dpi. Generally, anything that you can hold in your hands should be designed at or above 300dpi. It is especially important to note that though you can go down in dpi, you cannot go up without quality loss (when working with rasterized elements). Therefore, as long as your processor can handle it, it is best practice to work at 300 dpi or the maximum for your specific printer.
Depending on the size of a particular piece, you may have to design for perspective resolution. In other words, a billboard, from the road, appears to be a couple of inches wide, so therefore the dpi can be much lower (often around 18-20 dpi).