PDA

View Full Version : Lightbox with even light???



JoelBelmont
23-Feb-2009, 22:20
I am photographing (digitally) my 4x5 negs to make contact prints, and am having a hard time finding a small lightbox (10x12" to 12x18" give or take) with EVEN light. I bought a logan slimedge? and found it uneven at both ends. Looking on B&H both "Just" and "Hakuba" are supposed to be evenly lit (as close to $200 I would hope so)... just wanted to know if anyone had a recommendation...?

Thanks.

Eric Woodbury
23-Feb-2009, 22:28
This is why they make scanners. They are corrected for this. If it is just the ends, then buy a bigger lightbox so the ends are outside your pic. Making a lightsource perfect is very difficult. You can add more diffusion, but more diffusion is inevitably less light.

JoelBelmont
23-Feb-2009, 22:45
I am photographing, at times, 200-300 pages (4 to a page) of 4x5" negs (a backlog of work), so scanning is not a timely option. They are B&W, so color is not important... just even light to render the negs correctly. I am with you on the larger surface... I am currently looking at the hakuba Lightviewer 7000 PRO (8.5x11") which should give me at least a little more edgeroom than the 8x10 that I have now. Still would like any recommendations on affordable lightboxes with even light.

Eric Woodbury
23-Feb-2009, 23:03
You might make your own. Get a larger piece of white plexi and put a bunch of lights behind it. In front of that, a clear piece of glass on which to put your negs. (If you are having problems with newton rings, use non-glare glass.) Using a medium to long lens, focus on the glass and shoot at a bigger f/number. The plexi will act like an oversized light box and the glass will give you a flat surface. Being away from the plexi will place the plexi out of focus. It may seem weird, but even plexi is not 100% diffused and that means you can have some imaging through it. Placing the focus in front of the plexi helps to blur it more. Also, as you won't be using fluorescent tubes in close proximity to the plexi, they will be even more blurred. And finally, mask the excess light around the negs.

Another option, find an old light box from a commercial camera used for making plate negatives. It would be something that an old newspaper would have.

Nathan Potter
24-Feb-2009, 09:09
My old solution to this was to use a home built setup. The copy camera was enclosed on top of the lightbox to eliminate extraneous light from the outside. The films were arranged on clear glass (12X 12 inch format IIRC) and below that was a piece of white cardboard at about 45 degrees from the glass and film copy plane. Then I simply used an electronic flash at about 12 feet distant to expose the film (In your case to capture a digital image). You'll need to sync the flash to the camera thru a long flash cord but should not be a problem.

The idea was that at a great distance between the flash and the white card the variation in intensity is negligible. I used an auxiliary tungsten light directed on the white card for focus then switched that off during electronic flashing. But your digi will need an external sync outlet unless you rig a slave unit that will be actuated from the digi. Anyhow you get the idea and it can be a fast copy technique.

Nate Potter, Austin TX.

DarkroomDan
24-Feb-2009, 09:16
I use an x-ray viewer that I got for free when a hospital was remodeling. I don't know where one would look for these but, since they are quite expensive new, I would think someone must salvage them. They come in a lot of sizes. The viewing area on mine measures 17 x 28 inches and is very high quality opal glass. It was originally mounted in a wall but I built a stand for it so the glass is now a table top in my studio. I have a small (10x12) PortaTrace unit next to my enlarger in my darkroom.

Dan

Thebes
3-Mar-2009, 11:49
I used to have an old 4x5 contact printer that gave an incredibly even light. About the size of a large toaster, and if you can still find one it would probably cost mostly for shipping. I don't recall who made it.

Archphoto
3-Mar-2009, 12:03
Just made some good lightboxes but they were never cheap.

Gordon Moat
3-Mar-2009, 12:19
Try Porta-Trace, also sold under Gagne brand. The two bulb versions are quite good. Construction is strong, but not elegant. You might opt for the wood version over stainless if you want something that looks less industrial.

Ciao!

Gordon Moat Photography (http://www.gordonmoat.com)

Drew Wiley
3-Mar-2009, 13:17
Everybody and their cat makes a lightbox. Very few actually have even illumination.
The apparent trick is to put a thicker piece of white plastic or more heavily frosted
piece of opal glass on the device to increase the Lambertian scatter, but this also
drastically cuts back the amount of light being transmitted. It also changes the color
temperature. There's also the issue of the ballast. What might seem like a constant light to you might not to film, if you are using the light box for actual photography. Then the quality of the base diffuser becomes an issue, and how this affects both light distribution and color temp. And bulbs vary considerably in quality. In other words, there are light boxes and there are light boxes. Which explains the dramatic differences in price. Maybe you just need something simple, maybe you need the real
deal. Just be aware that the specs can be very misleading, and that they are generally
telling you, at best, the color temp and CRI of the bulb itself, not of the cumulative system.

Frank Petronio
3-Mar-2009, 22:03
One easy, very even source of illumination is the sky, either clear blue or solidly overcast. You could set things up so you shoot up and through the film resting on some glass, frosted or anti-newton if needed. Get a Laz-e-Boy and sit underneath.... maybe get an assistant topside to exchange negatives and snap away.

Some of my most difficult studio product shots were solved by taking the object outdoors when the art director wasn't around....

Struan Gray
4-Mar-2009, 00:59
Buy a 4x5 enlarger head with a glassless carrier. Or, better, a 5x7 head and use the center part only.

There were also slide dupers for 4x5 which used a built-in strobe for the lighting. The Bowens Illumitran seems to be the most common model on the used market, but others like Elinchrom made them too.

cjbroadbent
4-Mar-2009, 02:30
You could use a ring-light strobe in the bottom of a box. This thing here is 100% even.
It took an hour to cobble together. The hardest part is sawing a piece of persplex to fit in the top frame.

Gordon Moat
6-Mar-2009, 16:44
http://www.imagectrl.com/english/light/#/light-table/

I'm just evaluating this at the moment on my MacBook Pro. It works extremely well with the LED backlighting. I might actually pay the small license price and continue using it, instead of carrying around my mini light table.

If you already have a laptop with a nice monitor, then this is a good solution. While it is primarily a lightbox replacement, I can imagine other uses.

Ciao!

Gordon Moat Photography (http://www.gordonmoat.com)