caustics
Caustic (optics)
Caustics made by the surface of water.
In optics, a caustic is the envelope of light rays reflected or refracted by a curved surface or object, or the projection of that envelope of rays on another surface. The caustic is a curve or surface to which each of the light rays is tangent, defining a boundary of an envelope of rays as a curve of concentrated light.
Hiding Images in Plain Sight
An Article by Matt FerraroI recently made a physical object that defies all intuition. It's a square of acrylic, smooth on both sides, totally transparent. A tiny window.
But it has the magic property that if you shine a flashlight on it, it forms an image.
Caustic Engineering
An Article by Geoff ManaughA piece of milled plexiglass acting as a projecting lens; via the Computer Graphics and Geometry Lab at the École Polytechnique Fédérale de Lausanne
New milling techniques applied to glass and plexiglass panels could be used to “create windows that are also cryptic projectors, summoning ghostly images from sunlight.”
[Pauly and Bompas] hope that the technique will be used in architectural design, to create windows that mould sunlight and throw images or patterns onto walls or floors,” which, if timed, milled, and manipulated just right, could produce a slowly animated sequence of images being projected by an otherwise empty window during different times of day.
Architectural Caustics
A Research PaperTo control the shape of a caustic pattern generated by a specular or refractive surface, we need to solve the inverse problem: how can we change the surface geometry, such that incident light is redirected to produce a desired caustic image?
In the Eye of the Beholder
Haven't you noticed?
I remember my mother sitting me down at the age of about five with pencil and paper to draw an acacia tree in the yard while she busied herself with her own sketchbook.
After a while she came over to see my efforts. “Splendid! But haven’t you noticed how the trunk narrows as it rises? And see how the branches flatten out sideways, not like that oleander over there, where they all go up at a steep angle. Now don’t rub that one out, just do another drawing to compare with the first one.”
Wordless questioning
The comparison of forms raises questions and drawing can be employed as a wordless questioning of form; the pencil seeks to extract from the complex whole some limited coherent pattern that our minds and eyes can grasp. The probing pencil is like the dissecting scalpel, seeking to expose relevant structures that may not be immediately obvious and are certainly hidden from the shadowy world of the camera lens.
Outlines
Photography teaches us that the very act of putting a line around the edge of an observed object is an artifice. Such outlines rarely appear in photographs, or, for that matter, in nature, and yet…and yet?
An outline sketch that bears little relationships to the so-called objectivity of a photograph might actually transmit information to another human being more selectively, sometimes even more usefully, than a photograph.
If the brain is unlike a camera in actively seeking outlines, there is the strong implication that “outline drawings” can represent, in themselves, artifacts that may correspond more closely with what the brain seeks than the charts of light-fall that photographs represent.
Agents of thought and experiment
The act of drawing serves to remind us that hands are agents of thought and experiment. Photography has a great future, but no matter how much ancillary wizardry photography accumulates, it will not be in competition with “drawing” in the broadest sense of that term. There will always be a role for exploration by the hands, encumbered by no more than a piece of ocher or a stick of charcoal.
Its practical utility is as a manifestation of the mind struggling with the meaning of what it encounters and what it wants to explore.