Raised or indented II

Reader J.W. emailed regarding Monday’s Raised or Indented? entry below with an excellent example of his own image of sand dunes. It seems that J.W. is an expert at making sand dune images that “flip” the wrong way (“it drives me crazy”). I’d say that’s a worthwhile artistic talent, not a problem! So J.W. posed this question: “Is there something that I can do to make it look right all the time?”. The short answer is “no”, but a mirror (left to right reversal) will work with some images, and turning an image upside down will work with others. But my main advice to J.W. would be to exploit his natural talent, and produce something that will drive others crazy!

Book recommendation: Perception and Imaging, by Richard D. Zakia (about US$27). Excellent stuff. I have the first edition, which is a must-read, so hopefully the 3rd edition is even better. I’ve ordered a copy.

Here’s another example of the effect, this time using tonal inversion (Photoshop “Invert”) to flip the visual effect from raised to indented. Mouse over and out, observing the sand in the foreground as the image flips from normal to inverted—is it flowing down or up? Are the footprints uphill or downhill?!

Are the footprints raised or indented?
(click to see both images side by side)