Scans and Resolutions

Resolution for Halftone Scans
Scanning resolution (pixels per inch or ppi) is determined by the line screen (lpi) used for each press and available stocks.

• COLDSET WEB (Uncoated Stocks):
  4-Color Process:
  85 to 100 lpi scan resolution
  200-250 pixels/inch (ppi)
  Black and White (Grayscale):
  85 to 100 lpi scan resolution
  200 pixels/inch (ppi)
• SHEETFED
  Coated Stocks:
  150 to 200 lpi scan resolution
  300-400 pixels/inch (ppi)
  Uncoated Stocks:
  133 lpi scan resolution
  200 pixels/inch (ppi)
• Rule of thumb is to scan twice the line screen (lpi) required if placed at 100% or below into a page layout program. If enlarging a photo, do not enlarge more than 120% in the layout. If enlargement is greater than 120%, use the formula:
  

  (lpi x 2) x % = ppi

  For example, a photo being enlarged at 150% and using 133 lpi, the formula would be: (133 lpi x 2) x 1.5 = 399 ppi (or, rounded up to 400).
• If type is used in a scan or Photoshop layout, set or scan the resolution to 300 pixels/inch minimum. Anything below 300 will make type look jagged or fuzzy and hard to read. BE SURE that black type only shows 100% on the black channel of Photoshop Type with color in all four channels will not register on a web press. If creating type in color, make sure that a maximum of three channels are used for that color.
• Note: Best file formats to save images are .tif or .eps formats. JPEG (.jpg) files have a loss of information and are not recommended for sheetfed work, but can be used for coldset web printing. Do not use .gif formats or graphics from web pages!! These are low resolution files and will not reproduce correctly. Do not use PICT (.pct) or Windows Metafiles (.wmf) as these can also cause unexpected results.

Resolution for Line Art / Bitmap Images
Scanning resolution is important to keep logos or line art images as clear and crisp as possible.

• COLDSET WEB (Uncoated Stocks):
  4-Color Process or Black and White:
  400 pixels/inch (ppi)
• SHEETFED
  Coated Stocks or Uncoated Stocks:
  600 pixels/inch (ppi)
• Keep bitmap images at 100% or smaller. Do not enlarge them. For best results, save these images as .tif files. The color of these images can be changed (to spot or CMYK) in a layout program.