By: Nathan Segal
Printing is a challenge in computer graphics,
largely because there's a tremendous difference between screen-based
graphics and what you see on paper. This section offers tips that you
can use for your home or office printer and provides additional
information in case you choose to use an imaging professional.
1. RGB to CMYK
Colors that work in the RGB color space are often out of gamut in the
CMYK color space; meaning that what you see on the screen cannot be
printed using color inks. Other print issues are different RGB spaces
among scanners or monitors, a different CMYK space among printers and
printing presses and your monitor going through color shifts as it ages.
2. Use a Commercial Printer
If you choose to use a high-end commercial printer, do all of your
work in RGB. DO NOT convert your print files to CMYK. If you're doing
high-end art repro, you can send your RGB files and they'll do the
conversion for you but expect to pay big bucks.
If you're going to a local copy center, you'll need to convert your
files to CMYK yourself. If you send them RGB files the results are
likely to be unpredictable.
It's important to realize that converting your files to CMYK will
cause you to lose a great deal of color data. Worse, if you manipulate
the images after converting to CMYK, the color data loss could posterize
your image.
Ask your printer for their color profile and a print that you can use
to calibrate your system to theirs. Also, be sure to ask them what file
format they use and guidelines for output. This information varies from
printer to printer.
3. More Control
If you want more control over the CMYK process, check out: "The
Complete Guide to Digital Color Correction." This volume explains how we
see color, what the differences are between human and camera perceptin,
and how to work with a color wheel. You'll learn about display issues,
including monitor calibration and resolution, color palettes, and
consistency across varying platforms, operating systems, software and
more.
4. Page Layout
Check your layouts and make sure electronic documents match the
printed page size otherwise you could get an unpleasant surprise later.
5. About Graphics
When manipulating graphics, I recommend the use of an image-editing
application such as Photo-Paint. Don't use these functions in Draw
because this will add to processing times when you send your files to a
commercial printer. Instead use Draw for page layout only.
6. Screen vs. Print Resolutions
You will need to use different resolutions depending on the final
output. As an example, screen resolutions, gives you an image size of
72dpi; whereas for printing, you need to use a resolution of 125 -
400dpi, depending on the final output.
Note: Don't use screen images as they are only 72dpi. They might look
great on the monitor but the printed result will be highly pixelated
and will lack sharpness and depth.
