Client Provided Images & Sending to Press

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Images for printing on press:

RASTER images (working in Photoshop):

  1. Ask for original images.
  2. Request .tiff, .raw, or .psd files. Generally, .jpg and .png files can work, but ONLY if their resolution is good. Avoid.gif. files. An original .jpg straight from the camera is preferred, as long as it is not compressed too much. A very compressed .jpg results in artifacts, banding, or other undesirable issues. Try to get the original image. Never edit and re-save .jpg images as .jpg, every time you do you are adding more artifacts and losing color and image fidelity.
  3. Review for quality.
  4. Ideal image dimensions Rez min: 250dpi + at dimension(s) in inches/cm it will need to print. File size is not always an accurate measure, but anything under 500k is usually unusable.
  5. Typically used color profiles (check with your printer, some offer custom profiles for their presses):
    • U.S. Web Coated (SWOP) v2 for Magazines
    • ISOnewspaper30v4GCR4 for NYTimes newsprint
    • US Newsprint (SNAP 2007) for Generic newsprint
    • U.S. Sheetfed Coated (SWOP) v2 for packaging and brochures
    • U.S. Sheetfed Uncoated (SWOP) v2 for packaging and brochures
  6. Total ink coverage: Using the Info palette in Photoshop select panel options and Total Ink. Check denser areas of image. Add C+M+Y+K, for Newsprint and if the sum is more than 240, then it may be too much ink. Magazine paper can handle 280-300 or even higher if it is high quality. Usually applying a color profile as a final step will fix these issues. Check with your printer for their press specs.
  7. Do NOT multiply too many layers in PS … this can result in creating colors that are unprintable (see 8). If you do work this way, then as a final step, create a final flattened file and merge the layers, then apply the appropriate color profile.
  8. Change images with 16 bits/channel down to 8 before sending to press.
  9. Adjust colors using Levels or Curves in adjustment Layers.
  10. Avoid using Brightness/Contrast … Levels or Curves are far superior for adjusting contrast. They can also be used to adjust color channels separately.
  11. The major issues with Newsprint involve the lower end of mid-tones … simply making whiter whites and darker darks does not make it better.

VECTOR images (working in Illustrator):

  1. Unless printing SPOT colors, convert them to CMYK.
  2. Convert RGB to CMYK.
  3. Be sure white is NOT set to overprint.
  4. Colors can be set to overprint if you want that effect of transparency. Edges of shapes can be set to overprint for trapping.
  5. If printing BW, be sure that black is NOT a Rich Black (built of CMYK).
  6. Be sure there are no embedded or raster images.

Color Gamuts (color spaces)

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color_Gamut
Visible color space with approximate RGB, PANTONE®, CMYK coated, and newsprint gamuts. Image credit: Wade Dansby

It’s important to remember that in the entire visible color spectrum we can only reproduce a limited amount. Whether it is on screen with pixels or in print with inks/toner there is only a certain range of colors that can reliably be shown or printed.

RGB (or what you see on your TV, monitor, or mobile device screen) has a pretty wide gamut (color space) but it is still far short of every color you can possibly see. As technology improves, the RGB gamut is increasing (e.g. Colormatch RGB, Adobe RGB 1998, and ProPhoto RGB). However, what you see on a computer screen may be irreproducible on press. Be sure when working on projects for print to use a color profile in applications like InDesign or Photoshop (e.g. U.S. Web Coated (SWOP) v2, U.S. Sheetfed Uncoated v2, and US Newsprint (SNAP 2007)) to ensure what you see on screen is limited to what can be printed on paper or other printed substrates.

RGB is written using 0–255 for Red, Blue, and Green pixels shown on the screen. (e.g. black=R0 G0 B0, white=R255 G255 B255, Green=R0 G255 B0, Yellow=R255 G255 B0), and so on).

Alternatively, Hexadecimal (aka Web safe RGB, base 16, or Hex) This color system is used by HTML, JavaScript, and other digital languages to represent RGB colors in code. This base 16 numeral system is written using 0–9 and A–F (or a–f), to represent values ten to fifteen. (e.g. black=#000000, white=#FFFFFF, Green=#00FF00, Yellow=#FFFF00, and so on).

CMYK is a limited color set used by printing presses, toner copiers, or your home inkjet Very small dots of Cyan, Magenta, Yellow, and Key (Black) inks are combined to form many different colors. Impurities in these inks prevent achieving as many colors as you might like on a printed surface. The color gamut can vary widely based on what substrate you are printing on (e.g. Coated paper, Uncoated paper, Tee Shirts, Newsprint, Vinyl, etc.). Some of these limitations have been ameliorated by press techniques using hexachrome, PANTONE® inks, or other SPOT inks. If you have high-end ink jet you may notice it has 6, 8, or even 12 colors to achieve an even wider color gamut. Even these can only approach a portion of what is possible to reproduce in the RGB space.

CMYK is written using 0–100% for amounts of Cyan, Magenta, Yellow, and Key (Black) inks or toner combined to form a color. (e.g. white=C0 M0 Y0 K0, Green=C100 M0 Y100 K0, Yellow=C0 M0 Y100 K0, and so on). In CMYK printing black can be just 100% of black ink or a darker form of rich black (e.g. rich black=C50 M40 Y35 K100.) Don’t ever use C100 M100 Y100 K100 as presses can only accommodate a certain percentage of ink coverage. This is usually no more than a total ink coverage of 260-320%, depending on your press and the paper being printed on. (e.g. C50 M40 Y35 K100 would = 225% total ink coverage.) Before printing, check with your press to see their press specs. They may even have custom color profiles that can be used in Adobe creative applications.

SPOT colors. These are the individual pigments (similar to acrylic paints) that are used on an offset press or silkscreen to achieve a pure single (or two or three or more) color(s). The PANTONE® system of inks is one way of creating SPOT colors (see below). There are other systems as well (e.g. TOYO, RAL, etc). Often when making stationery (letterhead, business cards, etc) SPOT colors will be used to achieve a clean pure color. These SPOT colors span their own color gamut, wider than CMYK’s. Colors include fluorescent and metallic inks. Tints using halftone dots or lines can be made of these colors.

PANTONE® is a proprietary SPOT color system that allows people to share a standard set of color choices. If most of your work is going to be printed on a web offset or gravure press (e.g. most magazine and newspaper advertising), since they mostly use the CMYK gamut there is a danger of selecting a PANTONE® Coated (C) or Uncoated (U) color that is not possible to accurately reproduce without using specific a SPOT color ink (CMYK is approximately half of this color space.) The PANTONE® Color Bridge is useful in selecting colors, which can nicely convert into RGB or CMYK analogs and crosses over well from C to U paper stocks. The company is periodically tweaking and adjusting its library, adding new colors, and creating new systems.