Answered by Don Schroeder, Fujifilm Graphic Systems Division

Question:
My printer recently gave me two proofs for one of my print projects, but the proofs don’t match – even though they were produced from the same machine. How can that be?

Answer:
There are many reasons why two proofs from the same machine may not match. Conditions and proofing devices vary greatly. While ensuring consistency in the environment and with a printer’s proofing device may seem daunting, the results make it quite worth the effort. The best proof-to-press match will result in a more productive and profitable pressroom for your printer and will make you a satisfied customer.

Some things that can cause proofs to look differently are:

• Environment: the placement of proofing machines in various room sizes, traffic patterns, doorways, direct ventilation, window placement, amount of dust, and room lighting are all contributing factors to consider when printer suppliers set up their proofing area. High levels of dust contaminants in the area, coupled with low humidity, can negatively effect color reproduction or even machine operation, which can ultimately affect image quality. It is recommended that print suppliers maintain a 30% to 70% RH non-condensing stable environment.

• Lighting: The ISO (International Standards Organization) specifies a 5,000 degree Kelvin light source for viewing proof and press sheets. It is necessary for print suppliers to create or purchase a color viewing booth based on those standards.

  Tips for lighting:

  • Lamps should warm up for 14-15 minutes to reach stable temperature.

  • Allow time for your eyes to adjust to the D50 illuminant.

  • Any ambient lighting that is not standardized should be eliminated or dimmed.

  • Bright colors on furniture or clothing should be avoided.

  • All surfaces surrounding the viewing area should be neutral gray in color with reflectance of 60%.

• Metamerism: Two objects that match under one light source may not match when viewed under another source. This phenomenon is especially significant in the graphic arts industry where color matches between two items are important.

  Tips:

  • View under correct lighting.

  • A spectrophotometer can analyze color in terms of three-dimensional color-space.

  • If two colors have the same coordinates using the specified light source, they are considered matched.

• Printing Stock: A better proof-to-press match will be achieved when the proof is made on the actual paper stock that is going to be used on press.

• Proofing Devices: Understanding the different types of proofing devices can play a key role in understanding your printer supplier’s productivity. Choices run from ink jet printers to costly technology-driven proofing machines. (We’ll outline the major types of proofing devices next week.)

Source: Fujifilm Graphic Systems Division. For more information, please contact Don Schroeder, Group Manager, Color Products at (800) 877-0555 or visit Fujifilm on the web at www.fujifilm.com.
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