Posted this over in WoodCentral and figure there might be some here interested in this subject.
We have five senses - touch, sight, hearing, taste and smell. Of the five, turnings engages primarily sight, often touch and, surprisingly, sometimes smell. (OK - so sometimes someone will thunk a bowl and generate a sound, but that?s uncommon). Maybe it?s only turners who pick up a turned piece - and smell it - trying to identify the wood and/or the finish?
Once you get beyond functional turnings - spoons, bowls, rolling pins, tops, etc. - you?re in aesthetic territory where the goal of the turning is to engage its audience, specifically, to engage one or more of the audience?s senses. And since most turned pieces are typically only looked at / displayed - sometimes while inside a display case - we?re working in a visual medium - and therefore - light. Normally we must rely on reflected light to convey the piece.
That leaves us with surfaces, real or perceived, outlines, shadows and colors. The turner attemtps to create an interesting form, may utilize coves and beads, ogees and combinations of curves and angles, perhaps some texturiing, piercings, or maybe exploiting the figure in the wood, some added color or some branded pattern and sand blasting, wire brushing and charring are not uncommon these days. All rely on the presence or abscence of reflected light to convey something to the eyes of the beholder. With the exception of pierced pieces, most of the time we?re focused on the light reflected from the OUTSIDE of the piece, wood being normally an opaque material. Until recently, TRANSMITTED light - from INSIDE the piece - was impractical, incandenscent lighting bringing with it HEAT. Wood reacts to temperature changes. And when the temperature changes are relatively large, and relatively sudden, it often doesn?t react well at all
Some turn wood so thin that it becomes translucent. But to see the effect, a light source behind/inside the piece is required - turned lamp shades being an example. Wood that thin tends to easily deform and is pretty delicate, often proned to splitting and cracking.
Along comes compact fluorescent light ?bulbs? - the same amount of light as a comparable incandescent bulb - with less heat. But there?s still heat - thin wood?s nemesis. And even ?compact? fluorescent ?bulbs? aren?t all that small and compact.
Riding over the hill - in all its shining glory - an answer to perhaps an unasked question - The LED. Light with almost no heat! AND - they don?t draw much electricity so they don?t need an external AC power source or flashlight sized batteries - hearing aid sized batteries will do just fine.
Imagine a thin walled lidded form with a finial - on a pedestal, an LED and its little battery hidden In the finial to provide light from above, and another hidden in the pedestal to provide light from below. Now imagine the internal light dimming, going out, then getting brighter. You?ll see light from inside passing through the walls of the piece to your eye slowly change to only reflected light from the surface of the piece - and back again to mainly transmitted light, low spots in textures and carving changing from dark to light.
Consider the effect of the color of the internal light source(s) changing, changing, the contrast of the grain in the wood changing, depending on the colors of the internal light source.
So, internal lighting can be used to exploit translucency
-thinner walls mean more translucency - means brighter
-the color of the internal light and the color of the wood?s grain can change the look of the wood relative to what it looks like in terms of only reflected white light.
Imagine a piece with a smooth series of uninterrupted blended curves, no shadow lines or textures at all. Then imagine its internal shape, rather than paralleling the outside profile, has a very different profile, varying the wall thickness to later, when the piece is internally lit, produce stripes and circles and patterns - of light and dark - lighter where the wall thickness is small, darker where it isn?t.
Have enough ?challenges? getting uniform wall thickness, and the thought of trying to intentionally change the wall thickness - where you want to? Already turning through the sides of a piece occassionaly? Exploiting translucency isn?t the only option when playing with internal lighting.
Leave the walls as thick as you?re comfortable with - and use piercing to let some of the internal light out for the audience to see, or see then not see and then see again somewhere else depending on the angle and the location of piercings of the piece.
Freed from relying only on reflected light, internal lighting can open up whole new areas of turning to explore. Got some ideas for exploitng internal lighting? Care to share some of them?