Whenever we learn something, there always seems to be a loop thrown in somewhere that reminds us that there is always something else to learn. So true is it in graphic design whether you work on the web or in print. Working in both mediums can be a total pain in the ass because there are so many differences in processes used to make the final project.
Such is the case with output sizes and colors. Oh, the dreaded terms such as "RGB, CMYK, BLEED, TRIM SIZE,"...the list goes on and it's enough to make your head spin in confusion.
Let's try to simplify things...
Matching colors between RGB and CMYK is a total pain in the pancreas. If you think you can just go about using the same color picking routine, guess again. Here are some tips on how to make the 3 major colors match between web and print work.
RGB-to-CMY relationships work this way:
Red. In most cases red is considered to equal 100% magenta + 100% yellow. The reflective MY-red is too yellowish compared to the transparent RGB-red, however. Hence, it may be better to reduce the amount of yellow to approx. 85%. Try using CMYK values of C=0, M=100, Y=85, K=0.
Green. In most cases green is considered to equal 100% cyan + 100% yellow. Again, the reflective CY-green is too yellowish compared to the transparent RGB-green. Hence, it may be better to reduce the amount of yellow to less than 100%, e.g. 85%. Try using CMYK values of C=100, M=0, Y=85, K=0.
Blue. In most cases blue is considered to equal 100% cyan + 100% magenta even though almost everybody knows, that this is far from true. The reflective CM-blue is much too violet compared to the transparent RGB blue. To get a closer match it is necessary to reduce the amount of magenta as much as about 30%, i.e. to something around 70%. Try using CMYK values of C=100, M=70, Y=0, K=0.
Depending on the colors you have picked, you could experience significant color differences between what displays on your monitor versus what you see in your final printed project.
Monitors are RBG devices and display colors using only Red, Green and Blue as the primary colors. These colors are added together in varying proportions to create a spectum of virtually millions of colors. The process is "additive" - in other words, the RBG process adds 100% each of Red, Green & Blue to produce White.
4-Color process printing is a CMYK process using Cyan, Magenta, Yellow and blacK (Cyan & Magenta are varying hues of Blue & Red) to create a spectrum of virtually thousands of colors. The process is "subtractive" - in other words, CMYK adds 100% each of Cyan, Magenta, Yellow to produce Black. As the combination of these 3 colors renders a brownish black, blacK is added as the 4th color to create sharp type and provide better color and contrast control.
There are more colors in the RGB color spectrum than there are in CMYK. As a result, not all RBG colors can be duplicated exactly with the CMYK printing process. Some blues in RBG, for example, tend to acquire a purple hue in CMYK.
CMYK colors are visible to the eye as a result of light reflecting off the paper and passing back through the CMYK layers. Because of this, CMYK colors tend to be somewhat darker and less brilliant than RBG.
Most photographs contain only colors that can be reproduced equally well in either RGB or CMYK and you do not generally experience significant color shifts in photo images.
Illustrations, logos, backgrounds, type and other graphic elements created by an artist MAY contain RGB colors that are not available in CMYK. This can result in significant color shifts when converting to CMYK for printing. Projects containing these types of elements should be converted and viewed in CMYK mode before sending out for printing. This provides the opportunity to make any color changes BEFORE incurring any pre-press processing costs.
Almost all Desktop Publishing software (even Microsoft Publisher) allows the user to convert, view and send print projects in CMYK mode.
Wherever possible, set the workspace in your Desktop Publishing software to CMYK mode BEFORE beginning your project. That way you can be sure any colors you pick can be faithfully reproduced in print.
If you are printing files created by someone else, BE SURE to CONVERT to CMYK and VIEW the file in CMYK mode before submitting for print to ensure that you are happy with any color shifts that may have occured in the conversion process.
Remember that almost all "full color" printing in North America is done using CMYK 4-color process printing. Although many presses are capable of 5, 6, 7 or more colors, the cost of adding these additional "spot colors" is prohibitive, particularly in quantities of less than 25,000.
SAVE TIME, MONEY and FRUSTRATION. Make sure you have converted ALL your files (including graphic images, logos and photos) to CMYK before sending them out for printing.
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Confused yet? Take a deep breath and a moment of silence as we look at dimensions and how to set up a project for print...the QUICK GUIDE...
If image bleed is required, set Image Size to 1/4" larger than final paper trim size. (ie: for 8.5" x 11" final trim size, set image size to 8.75" x 11.25"). CAUTION: Remember that 1/8" will be cut off from all four sides for projects where bleed is required when trimmed to final size.
If NO image bleed is required, you can usually get away with setting the Image Size to final paper trim size. Restrict text and images to within the "Safe Print" zones (about 1/4" from the final paper trim edges).
Convert artwork to CMYK mode, 300 dpi resolution. The preferred CMYK profile is US Sheetfed Coated v2. Both of these functions are available using the Mode command under the Image drop-down menu.
If at all possible, convert your final project to TIFF. This format is preferred as it eliminates any potential font concerns. If you send a PSD or other file format, you'll end up having to send the fonts and possibly some other files that they may need (such as font outlines). Again, if image bleed is required, set Image Size to 1/4" larger than final paper trim size. (ie: for 8.5" x 11" final trim size, set image size to 8.75" x 11.25"). Always remember that 1/8" will be cut off from all four sides for projects where bleed is required when trimmed to final size. If NO image bleed is required, set Image Size to final paper trim size. Restrict text and images to within the "Safe Print" zones (about 1/4" from the final paper trim edges).
Flatten all layers. (Flatten command is found under the Layers drop-down menu)
Convert artwork to CMYK mode, 300 dpi resolution. The preferred CMYK profile is US Sheetfed Coated v2. Both of these functions are available using the Mode command under the Image drop-down
menu.
Select Save As under the File drop-down menu and select "Tiff" format. Name the file and click the Save button. After clicking the Save button, select Macintosh Byte Order when the option screen appears (ask your printer about this). LZW Compression option should be UNCHECKED.
Assembling all Tiff files into a single folder will make your printer happy.