FP4 v FP4+

[cliveh]

Did anyone notice a difference between this upgrade? I didn't.

 

[Mick Fagan]

Well when FP4 Plus came out in the very late eighties there was a lot of hoopla about how good it was compared to FP4, then some time later FP4+ came out replacing FP4 Plus. To be honest I don't think the changes, as they were, were much more than incremental changes each time, if indeed there were changes at each name change.

That said, the current version of FP4+ would probably be substantially improved compared to the original FP4 film from the sixties. I've been using FP4 since the sixties and either my ability is better, or the film is better.

FP4+ is my go to film and I exposed two 4x5" sheets last week, development will be either tomorrow or Friday.

Mick.

 

[Ian Grant]

The current version is FP4 Plus which was introduced in 1990, maybe some was packaged or referred to as FP4+. The slight improvementsbetween FP4 and FP4 Plus had come from improvements in emulsion manufacture technology learnt from the research behind Delta 100 & 400 films introduced the same year.

Personally I didn't see a significant difference between FP4 and the Plus version, I cut my teeth with ex-Goverment/Military surplus bulk rolls of FP3 and HP3 which were half the price of FP4/HP4 important as a teenager at school The huge improvement of FP4 and HP4 was the emulsions were well hardened, you needed to be careful with FP3 and HP3 as they were prone to reticulation if you weren't careful with temperature control.

Ian

 

[Lachlan Young]

As far as I know, the major changes were FP3 > FP4 > FP4+ - there may have been some subtle upgrades since. Having found myself both printing in the darkroom & scanning all 3 of those generations of film in the last year or so, often side-by-side, it's quite interesting to make comparisons. As I understand it (from a podcast I heard a few years ago that toured Ilford's factory & interviewed some Ilford photo engineers/ chemists) the 'plus' version was conceived to allow new hardeners to be used (presumably Bis(vinylsulfonylmethyl) ether or similar, as per C-41 materials), but in order to do so, a near total reformulation of the emulsion(s) was required as (and this is my paraphrase from memory) 'the new hardener was not compatible with the ammonium salts we had been using, so we had to completely reformulate using sodium salts instead'. It speaks very highly of their abilities that they were able to do so with most end users being relatively unaware of the extent of work involved. That said, I do think there are some improvements I can see in the 'plus' emulsion - the grain is slightly finer, but it also seems a little cleaner & sharper overall - which would be consistent with a move to a much more controlled monodispersity from a largely monodisperse-ish ammonium digested make - and/ or the possibility that new knowledge about placement of iodide was used to help make it sharper (without necessarily using any more or less iodide). The jump from FP3 to FP4, on the other hand, is vast. You can see huge improvements in essentially every important metric - granularity, sharpness, usable highlight latitude/ separation, overall curve shape etc - even so, FP3 seems to have some qualities of tonality & colour response that FP4 seemed to rather iron out in favour of being 'better' and more neutral/ even in overall tonality. 1960s Tri-X was drastically sharper than FP3/ HP3, but FP4 at least pulled level - and without the quite significant granularity of mid 60's TX (it's up there with Delta 3200).

 

[Tom Kershaw]

from a podcast I heard a few years ago that toured Ilford's factory & interviewed some Ilford photo engineers/ chemists) the 'plus' version was conceived to allow new hardeners to be used (presumably BVSME or similar, as per C-41 materials), but in order to do so, a near total reformulation of the emulsion(s) was required as (and this is my paraphrase from memory)

Do you have a link or any idea of which podcast or interview this was? It sounds like a useful piece of audio.

 

[Neil Grant]

..I found the grain a little finer in FP4+ vs FP4 non-plussed. Finer, but a little mushier. I don't think it printed any better.

 

[Lachlan Young]

Do you have a link or any idea of which podcast or interview this was? It sounds like a useful piece of audio.

I'd need to go for a bit of a dig - I think it was late 2017/18-ish. It was a pretty throwaway line about 50 mins or so into the piece from one of the senior emulsion engineers - and nothing they said differed in any significant way from what Ron (Photo Engineer) had said on here about emulsion making technology/ change in technology over time.

 

[Tom Kershaw]

It was a pretty throwaway line about 50 mins or so into the piece from one of the senior emulsion engineers - and nothing they said differed in any significant way from what Ron (Photo Engineer) had said on here about emulsion making technology/ change in technology over time.

Ah okay, thanks. I thought there might be some particular insight from Ilford.

 

[DREW WILEY]

I still have a partial box of original recipe FP4 laying around here, useless by now. The emulsion was somewhat fragile back then, so there were protective paper interleafing sheets between each sheet of film. Otherwise, the characteristics changed only slightly. It would certainly be hard if not impossible to tell the prints apart. But I don't have any experience with the even earlier FP3.

 

[Lachlan Young]

Ah okay, thanks. I thought there might be some particular insight from Ilford.

If you have Ron's book, or have a dig through his posts, he explains the way that ammonia/ ammonia salts were/ are used to create more monodisperse grain structures - but by the 1970s/80s those techniques had shifted to become much more sophisticated and highly computer controlled means of making more tightly controllable grain structures - closer to fully monodisperse as opposed to monodisperse-ish.

 

[cliveh]

[QUOTE="closer to fully monodisperse as opposed to monodisperse-ish.[/QUOTE]

Can you please explain that in a way we can all understand?

 

[Lachlan Young]

Can you please explain that in a way we can all understand?

Start here

Then read this - specifically step 4, which eliminates ammonia from the make.

It really comes down to how tightly you can control the emulsion making procedures - a fairly monodisperse emulsion will offer a significant qualitative improvement over one with no control over pAg, but with emulsion making systems that use highly sophisticated computer control/ monitoring it is possible to make a given crystal structure at will & in highly regular form - thus enabling closer to fully monodisperse emulsions to be made.