Whilst I am sure ( PMK-25 ) buys a lot of film I'm pretty sure he does not buy 193,750 sheets of 5 x 4 at once......although the Batch number can break that number down a bit ( to the individual slitting of the parent roll that the actual sheet film is from. )
Also its just not possible to have a 'bad batch' each sheet film batch is tested in excess of 30 different times from coating to finishing. If a batch has a problem ( a very, very rare occurance ) it is destroyed. Stocks of that Batch ( and every other sensitised product ) are held at Mobberley until the expiration date of that batch ( and often beyond ) so we can process and try and replicate a customer 'occurance'.
Regarding pre-soak, firstly PE is without any doubt whatsoever technically light years ahead of myself and therefore invariably correct, I must though 'reflect' the opinions and procedures developed by our own technical service department, whose job is to advise on the best practice for our products.
They say 'the modern manufacture of emulsions means that to obtain optimum results with ILFORD film pre- soaking is not required' .
What Simon says is simple....I do not do it, I've never done it ( on any film ) its absolutely more of a North American thing than a European thing, although I am not saying no European pre-soaks....and if you do pre-soak any ILFORD film in any format it should have no detrimental effect on that film whatsoever, we don't say don't do it, we say you don't need to do it.
I cannot speculate further on the issue this customer is having before we have seen the affected negatives, it could be any number of things....
Simon. ILFORD Photo / HARMAN technology Limited