Temperature range to avoid mosaic effect?

[dancqu]

d
Common sense might say the wash times should
lengthen with each change, ....

I'll side with Common sense and Ilford. The Ilford
Sequence allows for increases in wash time with each
change of water. Much of the fixer is removed with the
first rinse. The second and third rinses each need more
time. The fixer to be removed is located deep within the
emulsion and is slow to migrate to the surface. Also,
the body of water as the medium of diffusion is
more throughly used. Dan

[Martin Aislabie]

I tend to do my film processing infrequently but in large batches.

I therefore would need a store of 20C wash water the size of a bath to do all the film washing

So I use cold tap water which in winter is 5C (ish)

Reticulation is caused by thermal shock to the emulsion and base of the film producing differential contraction rates

I minimised the thermal shock by after fixing filling the tank with 20C water then dribble in to my Dev Tank tap water at its 5C (or what ever)

I use a forced film washer - so the water goes in at the bottom and comes out at the top.

When the water coming out of the tank approaches the tap water temperature, I increase the flow rate.

Then after a few more minutes I turn up the wash water flow rate to allow my cascade washer to do its turbulent flow thing and leave it.

Washing in very cold water is slow, I at least double the wash times recommended to account for the lower water temp.

I have never yet had Reticulation issues - but as the saying goes - there is a first time for everything

Martin

[tac]

It was years ago, so probably won't apply to today's emulsions, but as for letting film sit in wash water for extended periods of time, I have had emulsions fray and wash off of the base support after sitting in room temp. soak water overnight. Not sure, but I think it was TX back in the early 80's.

Modern emulsions probably won't do that, but some (Efke?) may.

[Ian Grant]

All modern emulsions suffer from micro reticulation it's not the same as thev classic old reticulation, you might not even realise you have it.

But then ask yourself why your negatives are grainier than someone else's with the same film/developer/times/agitation/EI etc. The only thing they are probably doing different is keeping their temperatures stable from developer to stop bath then fixer & wash.

Ian

[Kirk Keyes]

Ian - can you point to some examples of micro-reticulation so I can see what to look for?

[Ian Grant]

Ian - can you point to some examples of micro-reticulation so I can see what to look for?

Micro reticulation is grain clumping rather than a problem with the gelatin as in conventional reticulations so it just looks like more grain than usual.

There were some articles written about 20 years ago I think in Darkroom Technique, I have a copy somewhere back in the UK. Helen Bach would be able to give you further references but she seems to have stopped posting on APUG.

Ian

[Kirk Keyes]

Ian - Can you give a more authoritative reference than DT for grain clumping? I guess I can dig out my old copies and see what they say.

[Ian Grant]

Most of my information etc is in storage back in the UK so I can't look up references etc. There were some research papers but most people took little notice because most good pro's & labs etc keep their temperatures fairly tight in any case so would never come across it at all.

As I said Helen Bach also refers to it occurring and we discussed it here on APUG a few times some time ago, and she would most likely have references. I only had 3 or 4 copies of DT so it must be roughly 86'ish maybe 87.

Ian