Building a Light Table

I'm building a light table. I'm going to use either 18" or 24" fluorescent
tubes. I have a nearby plastics shop which has acrylic and plexi sheets. How
fussy to I need to be about the colour of the acrylic and the type of bulbs.
Is there a norm or a "standard" which I should be using. Mostly the table
will be used for Black and White negs, and some larger digital negs. I may
do some colour negative in the future -- I do have a lot of existing colour
negs and slides and I want to make sure I don't need to build a second box
just for colour work. Also, how thick should the acrylic sheeting be? Any
recommendations on the type of blade to use to cut this material? (I'm using
a table saw). Thx. p.s. has anyone built a "hand-held" light surface to
previewing negs while they're still hanging wet?

In article HphIg.472850$iF6.159865@pd7tw2no,
"Alan Smithee" wrote:

I'm building a light table. I'm going to use either 18" or 24" fluorescent
tubes. I have a nearby plastics shop which has acrylic and plexi sheets. How
fussy to I need to be about the colour of the acrylic and the type of bulbs.
Is there a norm or a "standard" which I should be using. Mostly the table
will be used for Black and White negs, and some larger digital negs. I may
do some colour negative in the future -- I do have a lot of existing colour
negs and slides and I want to make sure I don't need to build a second box
just for colour work. Also, how thick should the acrylic sheeting be? Any
recommendations on the type of blade to use to cut this material? (I'm using
a table saw). Thx. p.s. has anyone built a "hand-held" light surface to
previewing negs while they're still hanging wet?

Why not just buy one? They aren't that expensive.

There are standards for the color temp. The CRI and the intensity of a
light box. You will find it exceptionally difficult and expensive to
meet these standards with a home made box.

--
To reply no_ HPMarketing Corp.

Alan Smithee wrote:
I'm building a light table. I'm going to use either 18" or 24" fluorescent
tubes. I have a nearby plastics shop which has acrylic and plexi sheets. How
fussy to I need to be about the colour of the acrylic and the type of bulbs.
Is there a norm or a "standard" which I should be using. Mostly the table
will be used for Black and White negs, and some larger digital negs. I may
do some colour negative in the future -- I do have a lot of existing colour
negs and slides and I want to make sure I don't need to build a second box
just for colour work. Also, how thick should the acrylic sheeting be? Any
recommendations on the type of blade to use to cut this material? (I'm using
a table saw). Thx. p.s. has anyone built a "hand-held" light surface to
previewing negs while they're still hanging wet?


Color temperature is a relatively non-critical item for the worker with
just one light table, since all items will be laid out on the only table
you own for item-to-item comparison. It's completely moot for
examination of negatives, color or black and white.

It is more important in a commercial setting, pre-press or whatever so
that a layout that spans more than one light table doesn't change color
as the bits are moved about and I suppose could also be important if you
are trying to match "on screen" scanned images to color transparencies.

Mike

"Bob Salomon" wrote
"Alan Smithee" wrote:
I'm building a light table.
Why not just buy one? They aren't that expensive.

Ditto. It looks you can buy one for less than the cost
of parts to make one yourself.

"Nicholas O. Lindan" wrote in message
link.net...
"Bob Salomon" wrote
"Alan Smithee" wrote:
I'm building a light table.
Why not just buy one? They aren't that expensive.

Ditto. It looks you can buy one for less than the cost
of parts to make one yourself.

With all respect. Good advice -- except -- I'm building the unit as an
undermount into a current work surface. I already have the ballasts that I
need sitting on the shelf waiting for a purpose (free). Basically I need
about $10 of wood and at most about $40 for the top, bulbs and electrics. So
$50 in materials for a custom unit that fits the space perfectly becomes
much cheaper than $300 (minimum) for a comparable a la carte box at B&H.
(Plus I just like buildin' things). My question was really about "type" of
materials to use. Seems most of the pre-built units are using 5000K or
Daylight tubes (is that 6500K?). I'm thinking two ballasts powering four 20W
tubes should be about right for a 24"x24" area. I'm thinking 1/4" to 5/16"
thick now in a basic white "sign" acrylic should prevent it from bowing or
cracking under weight. I wondering if acrylics come in different
"temperatures". ie. not exactly white, maybe with a bit or blue (cool) or
red (warm) or just go with a neutral white and let the bulbs do their thing
with the colour.

"Alan Smithee" wrote
"Nicholas O. Lindan" wrote
"Bob Salomon" wrote
"Alan Smithee" wrote:
I'm building a light table.
Why not just buy one? They aren't that expensive.
Ditto. It looks you can buy one for less than the cost
of parts to make one yourself.

$300 (minimum) for a comparable a la carte box at B&H.


When I hear 'light table for the darkroom' my mind must conjure
up a different image than the OP. I was thinking of ~$50.
I have a 20x24" old big-box style I got new on ebay for $25
or so - can't say I recommend it, I keep thinking about
getting one of the small ones I can tuck away next to the
pad of paper wedged in beside the enlarger.

I go check B&H: Got a 4x5 for $19.99...

Scroll down ...

Yikes, it _is_ possible to spend $330 for 7x10" [What
sort of a size is that me wonders? For all the 6x9"
negative shooters out there?]

What do you get for 16x more...? Looked at the web site

http://www.just-normlicht-us.com/us/...%2DBetrachtung

and can't figure it out. I'm sure a $20 unit is a bit cheesy and
a Normlicht is made from surgical stainless steel with gull-wing
doors, alloy wheels and Bosch K-Jetronic ... [but to tell the
truth it doesn't say so on the web site.]

Light panels can be cheap because they use the same peices parts
that go into backlighting LCD displays.

For color quality I would think Rosco has a $5.00 filter that will
fix anything.

Pays money ... takes choice ... picks up hammer.

In article .net,
"Nicholas O. Lindan" wrote:

"Bob Salomon" wrote
"Alan Smithee" wrote:
I'm building a light table.
Why not just buy one? They aren't that expensive.

Ditto. It looks you can buy one for less than the cost
of parts to make one yourself.

I built a 48"x16" one for around 150.00 using scraps of plywood and the
requisite color correct tubes fixtures-and sign grade plexi.
--
Reality-Is finding that perfect picture
and never looking back.

www.gregblankphoto.com

In article ,
"Greg \"_\"" wrote:

In article .net,
"Nicholas O. Lindan" wrote:

"Bob Salomon" wrote
"Alan Smithee" wrote:
I'm building a light table.
Why not just buy one? They aren't that expensive.

Ditto. It looks you can buy one for less than the cost
of parts to make one yourself.

I built a 48"x16" one for around 150.00 using scraps of plywood and the
requisite color correct tubes fixtures-and sign grade plexi.

But you don't have a color corrected box. Nor do you have any idea of
what the CRI is of your box.

Color corrected tubes are only one aspect. The actual color correction
depends on the color temperature once it has been reflected off of
whatever you put behind them as a reflector and what the plastic or
glass does after the direct and reflected light passes through it.

Then there is the matter of intensity and eveness of the light. A good
light box is not so bright that it washes out highlight detail or shows
too much of the shadow detail nor is it so dim that it does not show the
detail in the shadows.

Also a box for X-Rays has different intensity requirements then one for
photo as do ones that were made for grapic arts.

--
To reply no_ HPMarketing Corp.

In article . net,
"Nicholas O. Lindan" wrote:

"Alan Smithee" wrote
"Nicholas O. Lindan" wrote
"Bob Salomon" wrote
"Alan Smithee" wrote:
I'm building a light table.
Why not just buy one? They aren't that expensive.
Ditto. It looks you can buy one for less than the cost
of parts to make one yourself.

$300 (minimum) for a comparable a la carte box at B&H.


When I hear 'light table for the darkroom' my mind must conjure
up a different image than the OP. I was thinking of ~$50.
I have a 20x24" old big-box style I got new on ebay for $25
or so - can't say I recommend it, I keep thinking about
getting one of the small ones I can tuck away next to the
pad of paper wedged in beside the enlarger.

I go check B&H: Got a 4x5 for $19.99...

Scroll down ...

Yikes, it _is_ possible to spend $330 for 7x10" [What
sort of a size is that me wonders? For all the 6x9"
negative shooters out there?]

What do you get for 16x more...? Looked at the web site

http://www.just-normlicht-us.com/us/...%2DBetrachtung

and can't figure it out. I'm sure a $20 unit is a bit cheesy and
a Normlicht is made from surgical stainless steel with gull-wing
doors, alloy wheels and Bosch K-Jetronic ... [but to tell the
truth it doesn't say so on the web site.]

Light boxes can go into the thousands of dollars without getting all
that large. A properly corrected box for scanning is over a thousand
with 4 x 55W tubes and an electronic flicker-free ballast and variable
output without changing color temperature or CRI.

--
To reply no_ HPMarketing Corp.

A good electricall supply place will order 5000ºK bulbs for you. They
are available.
I use these and white acrylic plastic. Works well.

Frank
I used these and white a
Daylight tubes (is that 6500K?). I'm thinking two ballasts powering four 20W
tubes should be about right for a 24"x24" area. I'm thinking 1/4" to 5/16"
thick now in a basic white "sign" acrylic should prevent it from bowing or
cracking under weight. I wondering if acrylics come in different
"temperatures". ie. not exactly white, maybe with a bit or blue (cool) or
red (warm) or just go with a neutral white and let the bulbs do their thing
with the colour.