Notes on Ad Graphics

Raster vs vector artwork:

Especially when small type isinvolved, this is the most important thing to understand.
Vector artwork is based on outlines and fills: word processors, most PDFs, illustration software all produce vector artwork which remains crisp-edged no matter how much you enlarge it.
Raster artwork is defined pixel by pixel. Photograps and web graphics are raster artwork. The problem with raster artwork in print publications is that the output renders it in a dot screen, which may make it even blurrier than it appears on screen—even when it is a "high resolution" graphic. Where smaller type or fine linework are in a tint (a gray, for instance), the dot pattern of the printer will really interfere with the shape of the lines. So, if you are using small type or fine lines, the best path is through a page layout program like InDesign or Quark, or an illustration program like Illustrator... and avoid running the results through Photoshop! If you have questions, contact us.

File format:

PDF: The easiest file format for us to deal with. Note that PDFs can be generated from a variety of programs. If you generate them from Photoshop or other raster-based programs, type will not print as crisply as if you create the type and generate the PDF them from InDesign, Illustrator, Quark or similar programs. And be sure the PDF is in CMYK or grayscale.

TIFF: the preferred raster format, if you are working in Photoshop. Note that small or thin type will become fuzzier when printed than it looks on screen.

JPEG: JPEGs are acceptable if they are saved at the highest possible quality level (level 12 or "maximum" on most applications). The splotches you get on any lower quality level will look bad when printed—this is especially true for flat areas of color.

Other formats: Raw Illustrator files (.ai), EPS files, and raw Photoshop files (.psd) are acceptable. Other file formats may require work on our end and so be charged the addtional $50 production fee.

RGB vs CMYK, rich blacks, and overprinting:

There are two basic color systems in the computer world. Computer screens and web artwork use the RGB color system, and printers use CMYK. We require our files to be CMYK.

If at any point in the production process, you run artwork through a program operating in RGB colorspace, black and grays will emerge from that program as "rich blacks." This means that the black is made up of a combination all four color inks (cyan, magenta, yellow and black). It is almost impossible to hold these four colors in perfect registration when printing, with the result that rich black type and complex line art look fuzzy when printed. If you have the full version of Acrobat, you can check for rich blacks using the Output Preview tool, in the menu under "Advanced" and under that, "Print Production." This allows you to turn off ink plates and see if your black is actually 100% black (it will disappear when you turn off the black ink) or rich black (it will turn kind of a muddy gray when you turn off the black ink. We can and will fix rich blacks, but may charge for it.

When printing black against a color, it is also helpful to set the balck type to "overprint." This means the color will run continuously under the black, and so you will avoid off-color halos around the type where the ink is not perfectly registered. For those who pay attention to these things, we do not apply trapping.

The other problem with RGB vs CMYK is color shift. CMYK printed colors are more limited in range than RGB screen colors. If you design with bright colors in RGB, you may be disappointed to see the printed results much muddier. Better to be working in a CMYK color space from the beginning, so what you see is closer to what you get.

One final technical note: if your delivered file includes spot colors, these will be translated using our color tables; if you need to match to a particular CMYK, best to make colors into process colors at your end.

Resolution:

We ask that files and all component files be 300 dpi (dots or pixels per inch) in size. We can sometimes fudge using a lower resolution, especially for very light, vague background images. Note that the resolution we are talking about is the FINAL resolution: if you have a 150 dpi image that you reduce to 50% in production, your result is 300 dpi—on the other hand, a 300 dpi image that's enlarged 200% will only be 150 dpi when printed. Get out your calculator!

Type:

Be sure to embed fonts or convert your text to paths before sending. This is the default on most PDF exports these days, but especially if you're using an older version of software, it's good to double check.

________________________________

For more information, email John Barobs, or call us at 612-706-9060.

Minnehaha Media is a division of Hedberg Maps, Inc., devoted to making seriously great free maps. See Hedberg Maps’ custom services pages to find out other ways we can help you!