|Typical New55 PN when done correctly|
Copyright 2016, Robert J Crowley
Surprising chemical reactions that are essential
The reasons for all this may surprise you. This is a story about the origins of type 55 and what had to be done by Polaroid, and how New55 FILM overcame a big problem with the Polaroid method and made it all so much easier.
Polaroid made Type 55 PN from the early 60s up until 2008. The product was unusual because it used a Kodak-produced Aerecon film that was also used for aerial reconnaissance. This negative film was a single layer, cubic-grained emulsion similar to Kodak's well-known Panatomic-X, but on a thinner base and with other small changes. Kodak supplied this material to Polaroid over many decades and it was labeled SO-139, which is a special order number among many others that Kodak produced in smaller amounts. SO-139.
The purpose of Polaroid Type 55 was to produce an instant negative. The positive print, which plays a role in the development of the negative, was secondary.
When processed and finished correctly, Polaroid Type 55 produced a sharp and permanent negative with very high acutance due to the static nature of the monobath reagent (or processing goo, or paste as some call it) used. The chemical process is too complex to get into here but suffice to say that this method of developing a negative film had several important advantages in negative quality over traditional wet baths.
Removing the goo - the old days
Users of Polaroid Type 55 had to treat the negative in a clearing bath for it to be both sharp and permanent. The clearing bath was sodium sulfite - a solvent that was hard to get - necessary to remove the goo that would otherwise fade the negative if not removed. Endless questions and gripes over the source, availability and cost of the sodium sulfite and the clearing process continued throughout the nearly 50 years of production.
Sodium sulfite worked in two ways: The first was by dissolving the goo so it went into solution, then as a fixer to remove the residual silver halides present in the freshly developed negative. Polaroid even went as far as suggesting that users further fix the negative in standard fixer to assure permanence, but they gave up on that as too complicated for an instant film.
Polaroid also sold clearing buckets for the sodium sulfite so you had a convenient place to keep your negatives. If you have one you can still use it today, with sodium sulfite or Ilford Rapid fixer. They are quaint reminders of the old days, which are now gone.
Fast forward to New55 PN
When I started New55 in 2010, one immediate concern from users was the un availability of the sodium sulfite. They complained that it was hard to get, expensive, and always a problem. I said I would look into that problem among several others.
Getting rid of the new goo
After several months of experiments I discovered that instead of dissolving the goo, I could get it to curdle and peel off as a sheet. This was far better and quicker than the old way. It turned out that shocking the goo with a low pH further polymerized the goo and caused it to shrink and separate. Lucky breaks sometimes come and this was clearly one of them, but how to implement it was not immediately clear.
Reviewing all the fixers including the fixer that was once used in a monobath designed by Donald Qualls, I noticed that Ilford Rapid Fixer (IRF) was not only the more desirable ammonium sulfite, known for very quick action, but also came mixed with a generous dose of acetic acid which has a very low pH. Ilford Rapid Fixer is also available worldwide, and is inexpensive. A series of experiments showed that a 50/50 mix of IRF and water was acidic enough to curdle the goo, cause it to float off, and it fixed the negative extremely well. All of the series of New55 PNs seen on my flickr feed were processed that way except one which we will talk about later.
Please look again at the example of a properly processed New55 negative that I want you to take a close look at. I've uploaded a large file so you should be able to zoom in if you like to see the incredible detail available. It's at the top of the page.
Contrast this with a badly processed negative kept down here on purpose. I see these things posted on flickr sometimes and though we do need to share our failures too, there is no need for this kind of bad result. Some of the reasons this looks so bad could be:
|There can be artistic merit to weird|
results. But better to know how
to do this intentionally rather
-Peeling too soon. Wait 2 full minutes
-Not getting the negative into the fixer right away. That is necessary.
-Wrong fixer. "I alway use Kodafix" means a bad result.
-Letting the negative dry. This makes it very unsharp and likely to fade in weeks.
-Scratched. Handle more carefully to avoid it.
There you have it. It is simple. We've worked very hard to bring back the look of T55 which I achieve every time, and so can you.
As always, I welcome your comments.