HP5 film base

[sfaber17]

I was developing HP5+ 4x5 sheet film for the first time and found
the back of the film was soft and sticky when wet and
was more delicate than the emulsion it seemed.
I don't remember that from developing old HP5 35mm
many years ago. Is this well known or am I doing something
to the film by using fixer designed for color, or using Ilford
new citric acid stop bath? Developer was ID-11 1:1 in jobo
rotary tank for 10 min. 20 deg. C.

 

[summicron1]

Never had that happen to me. I don't know much about fixers designed for color, but I would not use them for b/w work since I suspect the chemistry of both the emulsion and the film base is different.

stick to b/w chemicals for b/w work. One key to good photography is eliminating as many variables as you can so the few that are left are the ones you want to control.

 

[john_s]

I haven't developed HP5 sheet film, but I've used colour fixer (C-41) for years for everything black and white without any problem. The pH is close to neutral, otherwise it's the same as b+w fixer.

 

[Rudeofus]

Color fixer is loaded with Ammonium Thiocyanate, which can soften an unhardened emulsion (and AFAIK, HP5+ is properly hardened). Now idea why this would affect the back side ...

 

[Ian Grant]

120 & some LF films have a gelatin coating on the non emulsions side this is to help stop curl and with LF films is used for retouching negatives. I'm not 100% sure without finding a scrap HP5 LF negative and checking but I'm fairly sure it does.

Ilford films are particularly well hardened and have been ever since the introduction of FP4 & HP5. the retouching layer can be affected by some chemicals Hyroxides for instance, I've not heard of issues with colour fixer, quite a few people use one of the Kodak colour fixers but fixers from other companies may well differ so you need to be aware what is safe to use. I'd stick to something like Ilford Hypam or Ilford/Kodak Rapid fixers.

Ian

 

[john_s]

Color fixer is loaded with Ammonium Thiocyanate,......

Some do. The C-41 fixers don't.

 

[Ian Grant]

Just checked an older HP5+ datasheet (1996) and it clearly states "Both surfaces of HP5 Plus will accept commonly used retouching media and are designed to resist surface roller marks when machine processing".

Ian

 

[Rudeofus]

Some do. The C-41 fixers don't.

US patent 6649331 provides formulas for C-41 process chemistry, and it shows that official C-41 fixer contains 90 g/l Ammonium Thiocyanate. I think it's (there was a url link here which no longer exists) that has no Ammonium Thiocyanate ...

 

[sfaber17]

Thanks for that info on the retouch emulsion layer. Maybe it was hardened normally.
The problem was if there was a water droplet on the back that was there for some time,
then it would smear and be a mess if I tried to wipe it off. If I just wick off any drops that
may be present initially and then don't touch anything until it is totally dry, I'll probably be OK.
I will try it with regular Sodium Thiosulphate fixer though and see if there is any difference.

 

[john_s]

US patent 6649331 provides formulas for C-41 process chemistry, and it shows that official C-41 fixer contains 90 g/l Ammonium Thiocyanate. I think it's (there was a url link here which no longer exists) that has no Ammonium Thiocyanate ...

I just checked my Kodak pdf docs. The one I use, Flexicolor Fixer, hasn't any thiocyanate, but there's a Kodak Flexicolor RA Fixer that does contain it. Both are for C-41 process. I don't know why there are two different ones.

 

[sfaber17]

I was using regular Kodak Flexicolor fixer. The RA version is for the rapid process designed for minilabs.