P3D Films & Techniques for copying

["Dr. George A. Themelis" <DrT-3d@xxxxxxxxxxxxxxxxxxxxxxxxxxx>]

>From the B&H ad in Popular Photography, I see three kinds of Kodak
Internegative and Duplicating film:

- SO279: Internegative.  Will make slides out of your negatives.
- 5071: Slide copying film balanced for Tungsten light.
- SO366: Slide copying film balanced for flash light.

I have used the first two.  The common advice is to buy either blocks of
film with same emulsion number or 100' rolls and roll your own film.  The
reason for that is that there is some variation in exposure and color
balance.  You will need to do a trial to figure the optimum settings.  Once
you have the filtration and exposure optimized then you can continue using
the same film emulsion.  The 100' rolls can offer significant cost
savings if you can use them.

Of course, you could also use regular slide film for slide duplication.  
This leads to high contrast which is usually undesirable but might be OK 
or even improve things in some cases.

The Internegative film is designed to remove the orange mask of the
negatives and boost the contrast.

For lighting I use the tungsten balanced film flood bulbs that I get from 
Porter's. I have also used a fluorescent light table which says it is 
daylight balanced (for viewing).  This gives a slight green cast that can 
be corrected with filters.

In terms of equipment I use my Minolta macro lenses, bellows, & slide
copier (I don't use the slide copier with the FL table).  Most of my slides
are in thin Albion mounts.  These fit in the slide copier.  Anything
thicker (regular cardboard, RBT) will not fit.  If you are not willing the
remove from the mounts then you need to find different arrangements, like
the FL table or a piece of glass with diffusers and light source
underneath.

I basically use these films only to improve certain stereo pairs by
altering them (exposure, magnifications, color balance).  I am not
interested in faithful duplication.  

-- George Themelis


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