Paul C. Buff, Inc. Technical Forum

How are tota lites better as a polarized light source? Or did I misunderstand your post? Also, define large light source. Even out largest softboxes can have PL gels attached (PLM's would be more difficult).

I have done a fair amount of artwork shooting, especially canvases for Giclees. Contrary to some intuition, my experience suggests you do not want a large broad light . . . this just causes large glare areas. I have had good results using a single 7" reflector with two layers of diffusion gels (to even out the pattern) and a polarizing filter, with a rotating lens polarizer.

I have even had good results with the light almost at camera position (This results in minimal enhancement of the canvas/paint texture). Moving the light to one side enhances the texture because it creates texture shadows.

A useful trick is to temporally place a mirror over a portion of the artwork, then you can really see the effect of rotating the camera polarizer in "tuning out" the reflections from the light source.

I've had to postpone action on this, but I'm virtually certain the guidance from P. Buff Tech support will be valuable. Either the white reflectors PBT recommended, or a pair of small softboxes with sheet polarizers should do it. Since high quality tungsten rated sheet film in 4X5 appears to be gone from the market (or will be soon), day-light film and light sources that match seem the best way to go.

I have successfully used E100G sheet (daylight) with the tota lights, using a 80A over the rear element of the lens, but I dislike it because of the color distortion to the eye, and the light loss, which makes my wide-open lens act like an f11 or worse....just plain hard to see stuff through it.

Good luck, and I'll try to report when I get further along.

I responded too soon, without reading the latest posts....sorry.

I use the Totas out of mindless habit. They aren't "better" except that I've always been able to light a large area very evenly (+/- 1/6 stop over the needed space). They were small enough so that I could carry them on location, and use them with a set of 12" mounted polarizers and Tota-frames. This pushes the design of Tota lights pretty hard. They are not symmetrically supported on a stand, and the T.frame is un-evenly loaded also. Without "barn-doors" they spill a lot of light...which bounces around off walls and ceiling and won't be polarized.

So a source that contains the light and is a more stable set-up is better. I agree that small lights may be fine for paintings, but softbox quality light is essential for 3D work, which I also do. I've used Totas in 3 sizes of the great Chimera Video-pro boxes with success, but only the smallest one I own allowed use with a polarizer sheet.

I will be honest and say I have never polarized a light. With that in mind, pardon me if the next question is dumb. Would it be possible to (gaffer?) tape two or more sheets of polarizing gels together to make a larger sheet? This should not appear in the lighting, only in specular highlights, which you want to eliminate anyway. If used on a symetrical modifier (square softbox or octobox) the lights can rotate and maintain light shape, but alter polarization as necessary (at least in my head).

You could tape pieces together. To make it less likely that this would show in pictures, the less tape the better. With hot lights, it may be hard to find tape that can stand the heat, depending on the set-up. I made extensions for my Tota-frames, which put the polarizers further away from the bulbs than normal by at least six inches. After that modification, I never scorched a polarizer.

I doubt there's any point in arranging lights that can rotate. I adjust the amount of glare that gets through by just rotating the lens polarizer, while the light polarizers are positioned so that their axes are the same. But I have not experimented with this.

A couple of things about the cross-polarization we're discussing: some polarizer sheets and lens filter combos don't cut off all wavelengths at the same point of adjustment. Some will allow blue wavelengths through when all others appear suppressed, so you can have a shocking blue highlight remnant---not good. But this only shows up when you try to block all highlights, not just some. Also, since some well-placed highlights are an important visual clue to the nature of the object you're photographing, it's important that you not over-do the polarization. Objects that are glossy may need to show that quality, at least a little. Otherwise, they look un-real and dead, almost putty-like.

Thanks everyone for responding to my post!
The tota lights have worked well for me and I have basically the exact set up that jbarber has, including the home-made extensions to keep the gels from melting but I would like to find a way to makes strobes work for my needs. I have a very large museum project comming up and I am concerned about the heat from the tota lights and also UV exposure for the artwork. My original plan was to buy a pair of Einstein's with the 7" reflector and put a diffusion gel and a polarizing gel over the reflector, just as Lupa suggests but, based on jbarber's earlier post, I am concerned about hot spots or an uneven light pattern.
Luap, it sounds like you were able to get an even light with two diffusing gels, is this correct?
By a "broad light" I meant a light that can cast an even light (within 1/3 of a stop) over a large area in a relatively small space. Sometimes I have to shoot very large paintings in an artists garage or basement painting studio. Like, jbarber, I need something I can take on location and set up quickly in a variety of spaces.
Soft boxes would get me an even light and I could tape sheets of polarizing gel together but that solution does not seem ideal because I have to take all this on location 4- 6 times a week and I am concerned about the setup time and possibility of expensive polarizing gels getting damaged.
Thanks in advance for any other advice you might have.

Our current 7" reflector or mainframe, has an 80 degree spread. This mean from centerline to -1f is 40 degrees in each direction (centerline to -1f is our standard of measurement in degree spread). The pattern is very even, even on a bare reflector. Double diffusion will broaden the spread a little, and even it out more. This would not be a bad choice for a small modifier.

Thanks for the info. I think for paintings I will give the 7" reflectors with the extra diffusion a try and hopefully I can avoid the same problem in the original post of this discussion. If that doesn't work I may try the beauty dishes.
Thanks again!

One more question. I will be shooting a lot of delicate artwork and I am concerned about UV exposure. I know that the Einstein's flashbulbs are UV coated and I am wondering if adding UV filtering gels to my set up would make sense or would it just be overkill?

Thanks!