Cleaning and hardening formula type 55

[Jeff_1630]

So I was looking through AA's polaroid book, in the....reading room, this morning and came across Don Leavitt's formula (30 g Potassium alum, 90 g sodium bisulfite, 1 L water). Has anyone tried this?

Being lazy, I normally use warm tap water and a little permawash. The idea of making the negs a little less prone to scratching is attractive though. Or should I just stop reading, sh*t, and get off the pot? (sorry, been spending to much time on Franks site)

[Ralph Barker]

For what little work I've done with PN55, Jeff, I've just used straight sodium bisulfite.

I'll be keen to hear if anyone having used the Leavitt formula adding the potassium alum has had better results, though.

[Dave Ditzel]

According to the 'Film Development Cookbook' by Stephen G. Anchell & Bill Troop, page 121 - "Acid hardners such as chrome alum and potasium alum are no longer recommended in fixers because they must be used in acid solution and thus directly and indirectly cause longer washing times. However, where it is necessary to harden films or prints, potasium alum can be used after washing."

I read somewhere, I think on Polaroid's website, that if you want to harden Type 55 after clearing in sodium bisulfite, fix the negative in Kodak hardening fixer for a few minutes.

I hope this is helpful to you.

[Bill Jefferson]

Listed on Polaroids web site clearing agent is 18% Sodium Sulfite

Bill Jefferson Sr. Evaluation Tech. 4X5, 8x10 Formats

[Larry Gebhardt]

Will hardening the negative protect it after it is dry? I have heard it would not, so i fail to see what the point would be, given that you have already washed the goo off in its unhardened state (the time I am most likely to scratch a negative).