Monthly Archives: November 2008

Illusion demos with animations, illusions and aesthetics

Leonardo Animated (or the New Leonardo Cartoon)

The illusion of movement when a series of images is animated is one we take for granted nowadays. However, here’s a small world first (I think) as new example.  It’s a new Leonardo cartoon.  Actually, there is a Leonardo cartoon already, THE Leonardo cartoon, in London’s National Gallery.  But that’s not a movie. Art historians use the term cartoon for full size drawings for paintings.  But now here’s another Leonardo cartoon, and this one is an animated movie. Maybe a bit short, that’s all.

Leonardo often made anatomical studies from viewpoints in a strict sequence as if moving round the specimen. Some years ago leading Leonardo scholar Martin Kemp pointed out that one famous set of studies, of the shoulder and arm with superficial muscles exposed, contains so many drawings it’s almost cinematic. In fact there are nine views, from three different sheets, which can just about be combined. The drawings are in the British Royal Collection. They have a great website, and here’s one of the Leonardo drawings, showing four arms.

Nine views is just barely enough for a slightly rapid animation.

Leonardo’s observation is so consistent that I only had to adjust overall proportions and contrast a little bit in some cases, in order to combine drawings from different series. It might be possible to make a smoother animation with more adjustment of the images, but I wanted to interfere with them as little as possible.

An effect that in some ways is even better is possible, with just the last two frames in the sequence.

For Leonardo in general, a fun site is the BBC one.  The Wikipaedia Leonardo entry is very good too, with stacks of detailed info.

My short movie may be the first made entirely from a sequence of Leonardo’s own drawings, but it’s not the first based on individual drawings.  Some brilliant, very professional animations were made from Leonardo drawings, for a show at London’s V&A museum in 2006/7.  (I believe the animation was done by Aardman of Bristol).  They developed their own sequences of images from individual drawings, of geometric shapes or machines, which they projected as 3D reconstructions, and then rotated and combined by computer.  I’ve found only one example still on the WWW, but it’s a beauty, based on his drawings of the regular geometric shapes called regular solids.

Ambiguous images, Optical Illusions

Figure/ground Balustrade Illusion

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Here’s another figure/ground effect.  A saint becomes a balustrade!  Almost any vertical figure whose profile is not too wiggly can be used for this illusion.  Below is a different version of it.  It’s a little more puzzling, because both saint and balusters, when seen as figure at the ends of the picture, have the same starry sky as background.  That’s done by making sure that when saint or balusters are seen as background near the ends of the row, they blur into the same starry night sky.


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Photoshop CS3 drawing tips

Making illusion images with Photoshop CS3 – layers

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If you’ve just used Photoshop to adjust photos a bit, you may not have needed to use layers. For any more ambitious stuff, they’re essential, and at the heart of what makes it such a powerful package.  As a demo I’ll use elements from my Halloween image – not maybe my finest hour, but useful for showing layers. This montage shows the basics of what you can do with them.  (According to me!  I’m not a real Photoshop wizard, and your comments and corrections would be very welcome).

Think of the montage as four separate images.  Within each of the four images, there are five layers, one for each witch, one for the muscleman, one for the sky background, and one blank, truly background layer. You select the layer you want to work in, and changes you make in one layer don’t affect the others. 

 

By working in one layer at a time, you can for example move elements of your picture round the screen (compare the top witch in 1 & 2);  change which elements are in front of which (compare the lower witch in relation to the muscleman in 1 & 2);  change the size of an element (compare the upper witch in 1 and 3);  darken or lighten an element (compare the top witch in 1 and 2 again); make en element more or less transparent (note the lower witch in 3);  or play with the overall colour and tonal scheme (I’ve changed all the layers that way in 4).

 

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Impossible worlds (inc. staircases), Optical Illusions

Convex/concave spacewarp

convex concave space illusion

This is about the simplest of all spatial transformations.  In the top picture, the mice are at risk from the cats.  In the bottom picture, the stairs have vanished, and as the eye travels along the picture from the left, a concave terrace turns into a convex, step shape.  There’s now a protective inside/out space-warp between the cats and the mice.  I adapted the scene from one I devised for my optical illusion cartoon story.  If you wanted to experiment with scenes based on this transformation, the essential scheme is as to the left here. Note that there must be no tonal contrast across the middle line, just in the middle of the image.

Topologically, I suppose the shape is just a saddle shape, as to the right, so it could exist as a rectangular, 3 dimensional shape, but it would be such an improbable one, and seen from such an unlikely angle, that it looks like an illusion.  For a fiendishly clever picture on the theme of inside out transformations, see M.C.Escher’s print Convex/Concave.  (Try that title in Google images, or find it on the official Escher website).

Ambiguous images, Impossible worlds (inc. staircases), Optical Illusions

Outlines, objects and apertures

Impossible shape illusion

 

This stag may look OK at first glance (well, you know, sort of…), but hang on, has he got three antlers, as at the top of the picture, or only two, as down by his ears?  Following on from the last post, it’s another example of what happens when apertures or gaps in the visual scene – like the segment of starry night in the last post – become objects. But with the stag it’s even weirder, because the middle antler, for example, starts out at the top OK, but by the time it gets down to the stag’s head, it’s become background.  Want to know more?  Read on!

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