Light - Beyond Just Reflected Light

Light - Beyond Just Reflected Light

Post by charlie » Tue, 27 Jan 2009 01:50:22



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 thats uncommon).  Maybe its 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. - youre in aesthetic territory where the goal of the turning
is to engage its audience, specifically, to engage one or more of the
audiences senses.  And since most turned pieces are typically only
looked at / displayed - sometimes while inside a display case - were
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
were 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 doesnt 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 theres still
heat - thin woods nemesis.  And even compact fluorescent bulbs
arent 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
dont draw much electricity so they dont 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.
Youll 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 woods 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 isnt.

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 isnt the only option when playing with internal
lighting.

Leave the walls as thick as youre 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?

 
 
 

Light - Beyond Just Reflected Light

Post by LEGEN.. » Tue, 27 Jan 2009 06:48:22



Quote:
> 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?

You could have a set, where the outside is quite different but there's
a pattern to the translucent areas that unites them.

The only thing about LEDs though is they have a very focused
directional light.  I don't know if you could get away with a single
light pointing down and expect it to get an even lighting of the
piece.

You could have a turning within a turning (or something else) with the
light source in between them.  The internal piece could have textured
surfaces to exploit the proximity of the light source.

-Kevin

 
 
 

Light - Beyond Just Reflected Light

Post by John » Tue, 27 Jan 2009 07:33:00




Quote:

>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
>dont draw much electricity so they dont need an external AC power
>source or flashlight sized batteries - hearing aid sized batteries will
>do just fine.

Actually its surprising how much heat several LED's together can put
out. :)

A hearing aid size battery will have quite a limited life span

Hearing aid batteries are in general 1.5V

Depending on choice of battery
Battery Size: Milliamp Hours:
675      600 mAH
13      260 mAH
312     130 mAH
10A     70 mAH
5A      35 mAH

If you want decent light from a high brightness LED, your going to need
30mA at least, let alone the voltage so more than 1 cell is likely

So you cab see with the best of batteries your only going to get 20
Hours, and in practice way less

Another thing to consider is that White LED's have minor colour
variations, that may have an impact of how bright they are perceived,
and may be affected by the wood colour. Although sold as white, they may
have a slight tint of pink, blue, yellow. With pure white being least
common

There some nice useless trivia

--
John

 
 
 

Light - Beyond Just Reflected Light

Post by John » Tue, 27 Jan 2009 07:47:11


In message


Quote:

>The only thing about LEDs though is they have a very focused
>directional light.  I don't know if you could get away with a single
>light pointing down and expect it to get an even lighting of the
>piece.

You can change the focus by changing the shape of the lens, only problem
is , the internal reflector is focused on the lens for maximum
performance, though any change will normally widen the light  pattern,
the intensity will drop the wider the pattern. A trick that can be tried
is to place one of these fancy glass beads in front of the lens, to
diffuse the light or if there is excess light it can be diffused with
petroleum jelly or grease proof paper (think professional photographer)

Another trick depending on what is being illuminated, say a banxia but
would be yo use a light guide, or the poor mans version an old Bic Biro
Clear plastic tube. The LED fits nice in the end, but DON'T glue it, any
glue on the lens will distort the pattern
--
John

 
 
 

Light - Beyond Just Reflected Light

Post by Bob Crawfor » Tue, 27 Jan 2009 13:33:39


I've been toying with an idea.

A center "core" of wood, say 3" square x 2" or 3" in height.  Laminate 1/4"
or 1/2" Plexiglas to this on the four sides.  Now laminate this block on the
outside with your wood of choice of sufficient size to make the form
diameter you desire.  On top of this block, laminate another piece of
Plexiglas to cover the block, followed by another layer of wood of choice
etc. until you get the desired working height.

Finish the bowl/vase/form inside and out.

Build a display stand/box with a center insert piece of clear Plexiglas
about 1/4" smaller than the diameter of the finished pieces' bottom.  Inside
the stand/box, install a small battery powered (or you could use standard
house voltage) light or leds.  When the piece is on display and the stand
turned on, the light should transmit thru the Plexiglas in the piece to
illuminate the "rings" both inside and outside the piece.  I can see so many
variations on this idea with some minor adjustments, like slanting the
Plexiglas rings during the lamination process or having the rings show only
thru the outside or inside of the piece.  I guess you could also segment the
Plexiglas rings with a contrasting wood as well.

Like I said, I've been "toying".  ;)

Bob Crawford


Quote:

>> 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?

> You could have a set, where the outside is quite different but there's
> a pattern to the translucent areas that unites them.

> The only thing about LEDs though is they have a very focused
> directional light.  I don't know if you could get away with a single
> light pointing down and expect it to get an even lighting of the
> piece.

> You could have a turning within a turning (or something else) with the
> light source in between them.  The internal piece could have textured
> surfaces to exploit the proximity of the light source.

> -Kevin

 
 
 

Light - Beyond Just Reflected Light

Post by Ralph E Lindber » Tue, 27 Jan 2009 22:32:32




Quote:
> I've been toying with an idea.

> A center "core" of wood, say 3" square x 2" or 3" in height.  Laminate 1/4"
> or 1/2" Plexiglas to this on the four sides.  Now laminate this block on the
> outside with your wood of choice of sufficient size to make the form
> diameter you desire.  On top of this block, laminate another piece of
> Plexiglas to cover the block, followed by another layer of wood of choice
> etc. until you get the desired working height.

> Finish the bowl/vase/form inside and out.

> Build a display stand/box with a center insert piece of clear Plexiglas
> about 1/4" smaller than the diameter of the finished pieces' bottom.  Inside
> the stand/box, install a small battery powered (or you could use standard
> house voltage) light or leds.  When the piece is on display and the stand
> turned on, the light should transmit thru the Plexiglas in the piece to
> illuminate the "rings" both inside and outside the piece.  I can see so many
> variations on this idea with some minor adjustments, like slanting the
> Plexiglas rings during the lamination process or having the rings show only
> thru the outside or inside of the piece.  I guess you could also segment the
> Plexiglas rings with a contrasting wood as well.

> Like I said, I've been "toying".  ;)

> Bob Crawford

  Have you tried turning Plex? I ask as I recall it tends to be brittle
and I wonder if it would shatter.

--
--------------------------------------------------------
Personal e-mail is the n7bsn but at amsat.org
This posting address is a spam-trap and seldom read
RV and Camping FAQ can be found at
http://www.ralphandellen.us/rv

 
 
 

Light - Beyond Just Reflected Light

Post by Bob Crawfor » Thu, 29 Jan 2009 02:39:29


Not yet, but this is an idea I've got planned for the near future.  I
imagine that with the plexi laminated between wood layers, the brittleness
shouldn't be a problem.  I suppose we'll see soon.  ;)

Bob

Quote:
>  Have you tried turning Plex? I ask as I recall it tends to be brittle
> and I wonder if it would shatter.

> --
> --------------------------------------------------------
> Personal e-mail is the n7bsn but at amsat.org
> This posting address is a spam-trap and seldom read
> RV and Camping FAQ can be found at
> http://www.ralphandellen.us/rv

 
 
 

Light - Beyond Just Reflected Light

Post by charlie » Sat, 07 Feb 2009 02:07:58


I turned acrylic rod - with a quarter inch single bevel bench chisel and
had no chipping problems at all.  Had to sharpen more often, but light
cuts were no problem.  Also turned some thick walled PVC pipe and had no
problem there either.

Today's plastics are NOT the same as the old WW II "plexiglass".

The idea of a segmented piece which includes modern clear plastic pieces
is intriqueing as hell.  With a "glowing rod", lit up by an LED on its
bottom face, you wouldn't even have to hollow the segmented piece in
order to get light out the clear plastic areas.

 
 
 

Light - Beyond Just Reflected Light

Post by charlie » Mon, 16 Feb 2009 13:02:29


Bob:

Did you ever get around to turning a piece with plex in it?

Only did a couple of piece using internal LEDs and have since
moved on to playing with jewelry ideas using some turned parts.

Did find a small light with very bright LEDs - at a pet supply
store of all places - but haven't started a piece to use it - yet.

Internal lighting has a whole bunch of possibilities - which I hope
SOMEONE continues to explore - AND share results.

charlie belden
afflicted with TADD
Turner's Attention Defecit Disorder
Oh look!  Some juniper to turn!

 
 
 

Light - Beyond Just Reflected Light

Post by Bob Crawfor » Thu, 19 Feb 2009 03:43:28


No Charlie, sure haven't.  I did manage to get a piece of 8x10 Plexi from
Lowes, just haven't had the time to start the laminating and such.  SOON
though!  ;)  I've been really pursuing the twisted finials lately.  I tried
the sandpaper wrapped around a dowel and set between centers on the lathe
and it works great!  While the belt sander worked well, the differing sizes
of dowels on the lathe makes creating different spiral angles a possibility
as well as spirals WITHIN spirals...i.e.. a 2" dowel for the initial spiral
and then using a 1/2" dowel for another spiral inside the first.

It just never ends does it?  lol

Hope you're well.

Bob


Quote:
> Bob:

> Did you ever get around to turning a piece with plex in it?

> Only did a couple of piece using internal LEDs and have since
> moved on to playing with jewelry ideas using some turned parts.

> Did find a small light with very bright LEDs - at a pet supply
> store of all places - but haven't started a piece to use it - yet.

> Internal lighting has a whole bunch of possibilities - which I hope
> SOMEONE continues to explore - AND share results.

> charlie belden
> afflicted with TADD
> Turner's Attention Defecit Disorder
> Oh look!  Some juniper to turn!