Gel Polarizers

[Robert C. McColloch]

Reference:
Calumet Rosco Polarizing Filter (part #RC3000) mentioned in a previous answer to a gel polarizing filter question.

My experience with glass polarizing filters, when many years ago I used a 35mm camera, this required rotation of the polarizer to the correct incident angle to the sun or reflection in order to get the desired effect (e.g., darkening of blue sky or reducing/eliminating reflection of water). Gel filer polarizers sound like the solution for LF - but, what arrangements have you experienced LFers made to accomodate such a polarizer for use of a GEL polarizer on your LF cameras (i.e., rotation)?
It seems to me that just placing a gel polarizor in front of a LF lens without rotating it to the correct incident angle will be just a blind exercise/guess unless you could look at the ground glass on the back as you rotate it. Then there is the problem of what kind of filter holder will accomodate this?

Any advice would be appreciated.

[Gem Singer]

Robert,

The Rosco polarizing filters are used to polarize the light from an artificial light source in a studio lighting situation. For example, by placing the Rosco polarizing material directly in front of the light source, it will help to remove the reflections and glare from glass objects being photographed. The Rosco polarizing material is not designed to be used like the conventional rotating glass filters that are screwed onto the front of a camera lens. It is made in the form of large sheets of plastic that can be cut into smaller sizes and shapes. Rosco filter material is used mainly for studio color film effects, and it is available in the choice of dozens of colors.

[Eric Woodbury]

Calumet makes (I guess they still make it) a hard plastic polarizer that was for use in gel holders and was optically clear. It's 100 millimeters square. To align, you look through it and figure it out, then put it in the holder and rotate the holder to the same orientation. Works fine.

[Bob._3483]

As far as I know, all the systems for holding gels (Cokin, Lee etc) rotate.

But, why not just use a normal glass polariser on the lens? Admittedly, filter threads tend to be larger than for 35mm lenses, but not by that much unless you are using very wide and/or very fast lenses...

Cheers,