I’ve been studying some design principles lately. One of the ideas that came to my attention was something called “Visuospatial Resonance” It can be described as a phenomenon in which an image achieves optimal clarity due to resonance between the spacial frequency of the image and the observer’s distance from the image. It’s basically a trickery of imaging where you use and overlay of the finer edges of an image and then lay that on top of a slightly blurred of the original. It can even make someone appear to be smiling at a distance and not so much when you examine the image close up. The Mona Lisa by Leonardo da Vinci has been cited as one of the first to use this before we had Photoshop to easily achieve this effect. He slightly blurred the edges of her lips and made the appearance of a smile at a distance view but up close it was obviously not a smile on her face. Trickery of the brain processing the image! Cool huh.
This video by a guy named Evan Sharboneau is absolutely spot on when it comes to explaining it. He is somewhat of a photo guru in terms of illusions. He has written an ebook and has some great tutorials.
Check him out at: https://www.facebook.com/PhotoExtremist/timeline or http://photoextremist.com/