Optical delusions

I’m back in Castuary (my term for that anxious period when the mold is in the kiln and you’re waiting to find out if you’ve just made heaven or hell in glass). As usual, it’s sending me into all kinds of odd musings.

For example, I’ve run across two different perception phenomena during this Castuary. First is what’s called the Moon Illusion–the full moon on the glassland horizon has been roughly as big as the sky lately, and Mom and I were discussing what caused it.

I figured it’d be a simple atmospheric magnification thing; you know, the light reflecting off the moon at a fraction of a degree above the horizon acts kinda like a telephoto lens, etc., etc. So I headed to the Web to find out about it and–surprise–nobody’s really figured out what causes it. There’s a nice writeup on the NASA website. Fascinating stuff.

The second phenom was closer to home. Take a look at these pics:

I don’t know about you, but I think these all look like standard faces. Convex, normally shaped faces, albeit faces with chewed-out noses and kinda odd lips. In fact, these are pate de verre molds and the faces you’re looking at are three-dimensional negatives, i.e., they’re hollow and we’re looking at what will be faces once they’re filled with glass, fired and molds removed, but from the back.

When I work on these molds, I don’t see faces at all; I just see holes that need to be filled with glass powder and frit. Apparently my brain has enough context to put these shapes in the proper perspective. Yet I document work in progress pretty assiduously with my studio digital camera, and at some point every one of these molds will invert themselves and become a real face in the photos.

I suppose the camera is flattening and isolating the images just enough that my brain has trouble coping. Hmmmm, it says, that’s the SHAPE of a face, and everybody knows faces aren’t hollow…so I’ll just fill in the blanks and turn this into a REAL face.

What I find especially fascinating, though, is that it doesn’t complete the job. If you look at the noses and teeth, for example, they’re only partially brought forward. The hidden bits aren’t filled in, which gives these “faces” the aspect of a fleshed-out skull. Kinda creepy, actually.

Interesting reminder that you can’t always trust your eyes, I guess.



  1. gary September 20, 2008 at 10:18 am - Reply

    What’s weird is when those “is it CONVEX or is it CONCAVE” message start fighting it out in your brain and the image never really pops into either state. Just so of sits there and mentally vibrates.

    (Hi Les!)

  2. Leslie Rowe-Israelson September 20, 2008 at 7:20 am - Reply

    Thinking all day about good vibes for the kiln goddess to do her magic for your pieces in the Bullseye kilns. I am waiting patiently (I am fibbing of course as I am not Patient at all) and will be with you in spirit when you go to take your pieces out . Let us all know how it goes. I am glad you have a course this weekend to help you not think about them until tomorrow. Les

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