I have been making Polaroid image transfers for about five years. During
that time I have explored many different techniques and made a lot of
mistakes, some of which I actually learned from! Strangely, making mistakes
and having images turn out quite differently than what you had envisioned is
a fair part of the attraction of transfers. Some suggestions based on my
experience follow.
Very high contrast images are especially difficult to transfer with high
rates of success. The dark shadows and high density blacks are more likely
to lift off and be lost during the transfer. Try to keep your image dynamics
toward high-key or "flat" lighting by either shooting in diffused light
(which we have in abundance through most of the year here in cloudy Seattle
where I live) or by persistent use of fill flash in sunny scenes with deep
shadows.
I use Fuji Velvia shot at 40 ASA/ISO for most of my work. Its extreme
resolution and sharpness along with luscious color saturation help to
compensate for the loss of precision and saturation that the image transfer
process involves. I often shoot with a slight warming filter and then make
further color compensations during the transfer exposure.
When I began doing image transfers I used the Vivitar slide printer unit
which is widely available. These days I use a 4x5 Polaroid holder (until I
can acquire the 8x10 format) and use an enlarger to transfer the image. The
enlarger gives me much more control over the process, but it does require a
darkroom.
I have been using the gelatin soak method for some time now, as I find it
enhances the sensitivity of the image and the color saturation. This method,
described by Polaroid in their Image Transfer procedure notes, involves
using standard Knox gelatin packages in warm water. I also use a warming
tray. The heat helps to keep the dyes mobile and to facilitate the transfer
of the gelatin matrix. This is probably also the reason that presoaking the
paper in a gelatin solution helps so much--it is compatible with the
chemical environment for the dyes. I also now do almost all of my
separations in a tray of warm water because it helps to lessen emulsion
lift-off.
One last note - I have also done experimentation with a variety of Japanese
"rice" papers and these can create a different and exciting look for the
image. Look for papers which have a fairly smooth surface and which are
strong enough to hold up to being wet without falling apart. The Japanese
Kitakata paper is excellent. Use a mister or spray bottle rather than a tray
to moisten these kinds of paper, and do not use a gelatin soaking. Good
luck, and have fun!….