Kevin, again, thanks so much --
I'm leaving all you wrote below because I archive things in
my sent mail - hope other PDMLers don't mind - I think your
info is very um illuminating - and I'm not surprised that
it turns up in something George Lepp wrote -- I used to read
him religiously. Having studied a bit of Microscopic
Petrology I knew about crossed Nichols. The prices you
mention are not
prohibitive.
Best,
Ann
"Thornsberry, Kevin L" wrote:
>
> Ann
> According to the Edmund Scientific website, polarizing film can be had for
> about $15 for a sheet 8.5 inches by 5 inches or a 2 inch square 2 pack can
> be had for $6.40. As I understand it you need two pretty strong strobes
> since you'll be losing a lot of light. To orient the films overlay your
> lens' polarizing filter with the film and rotate for miminum tranmittance.
> Mark the top of the film and the top of the polarizing filter in this
> orientation. Now when you install the film on the strobes and the filter on
> your lens make sure your marks are still on top. In the applications I've
> heard of the strobes were mounted on a bracket attached to the camera with
> one strobe on each side.
> To see an example of this technique in use go to www.leppimages.com and
> choose to view the Shoreline Print collection. The sand dollar picture
> labeled "Sparkling Embrace" (lower left on page 1) used the cross polar
> technique. Note it retains the strongest reflections withouth the image
> being overpowered. I'm not sure about the other two sand dollar pictures.
> I'm sure an email to [EMAIL PROTECTED] would yield a list of which of his
> images were made using the cross polar technique.
>
> Ann wrote:
> >Kevin - so glad you brought that up -- I mentioned it almost
> >a year ago when I first got on the list - no one seemed to
> >know about it. I was basically asking for exactly
> >what you explained - how to establish the angles. I was
> >thinking of using floods instead of flashes, tho for the two
> >auxiliary lights.
>
> >My idea was to "cross Nichols" looking through the camera at
> >the polarizer on the light source(s) rotating the polarizer
> >on the camera only 'til it turned black.
> >I have an awful feeling those polarized sheets are expensive
> >as all get out though.
>
> >annsan
>
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