Print Surprise: Optical Illusions at the Press



Optical illusions – where the perceived reality of a viewed object is different than the actual physical attributes being viewed – are interesting phenomena. Occasionally an unintended illusion will pop up in the print work here at our shop, and it usually takes a little convincing to prove to our press operators and art department that the problem is in the viewing…not a mistake in the print files or print process itself.

Gradients Can Trick the Eye

Optical illusion on press sheets

Above is the press sheet layout for a 4-up printed card which will later be cut out and folded in half. However, coming off the press, the 4-up sheets appear like the left side is darker than the right, especially on the outer side of the card. (In person, the effect was even more dramatic than it shows up here onscreen as it was printing on a metallic paper.) We were stumped at first as to what could cause this – the pdf file was preflighted, all the images were rendering correctly. We wondered about a problem with the press, the imagesetter, the layers within the pdf file. Finally, it took cutting a finished sheet apart by the crop marks to see that once separated, the gradients looked fine. Placed next to each other, the light to dark gradient tricked the eye into thinking one side of the press sheet was darker.

Gradient optical illusion




Repeating Patterns and Distortion

repeating pattern optical illusion

The 2-up sheets printed above have a decorative border with a repeating pattern that flows in one direction to the halfway point and then reverses its orientation for the second half on all four sides. If you let your eye wander slowly along the borders, especially the longer vertical sides, it appears that the borders are bent and not a perfect square shape overall. The eagle eyes of our press operator noticed the subtle “bend” in the lines and decided that either the file or the imaging plate itself was somehow warped. Placing a ruler or straight edge on the press sheet reveals that, despite what your eyes are telling you, the line is perfectly straight across all four sides of the paper.

Optical illusion of a square decorative border

You can read more about optical illusions and view galleries of them at a surprisingly great number of websites as many people find the tricks our eyes can play on us to be a fascinating topic.


Call us at 828.684.4512 for any marketing needs. As a printer, we understand communication and design. Your printer should be able to provide you with the latest information, inspiration, technical advice, and innovative ideas for communicating your message through print, design and typography, signage, apparel, variable data printing and direct mail, integrated marketing and environmentally responsible printing. If they can’t, you have the wrong printer! The best advice, always, is to ASK YOUR PRINTER!

ImageSmith is now partnered with Extreme Awards & Personalization – our in-house partner providing custom engraved trophies and awards for employee recognition programs, sporting events, and promotional needs. With our new sister company, we will be sharing space, resources and expertise in a collaboration designed to further provide you with one place to meet all of your marketing needs… Under One Roof! Visit them online at or call direct at 828.684.4538.



Call us at 828.684.4512. ImageSmith is a full-service print and marketing provider located in Arden, North Carolina. Contact us at ImageSmith for quotes on all your print and marketing projects, and more useful tips on how to create custom, effective, high impact marketing solutions.