Ilford FP4 Plus

[tribal-warrior]

I haven't shot b&w film for ages and I used to shoot Ilford FP4 on a regular basis years ago. These days, I notice there's a film called FP4 Plus. Out of curiosity, what would be the differences between regular FP4 and FP4 Plus? With regards to processing, is Plus fairly forgiving when it comes to temperature? When we were taught 35mm film processing in the mid 90s, the importance of temperature wasn't really drilled into us. In fact, I never bothered to check or adjust the temperature of the chemicals back then. I was more concerned with the right quantity / mix of chemicals and processing times. Most films came out fine except for one (an FP4 film) which was super grainy. Even a 4 x 6 inch print made from the processed film had massive amounts of grain. It looked more like a 6400asa film. I mentioned this to someone else, wondering what was the cause and they reckoned it was the wrong temperature.

Sometime hopefully, maybe in the future, I'd like to get into large format 4 x 5 inch b&w film shooting and processing. And I'd like to use a film which is medium speed, fine grained and fairly forgiving when it comes to temperature during processing. Would FP4 Plus fit the bill here? I do admit I'm biased towards FP4 because that's what I'm used to shooting when I did a lot of b&w. And this time around, I'll make a point about keeping temperatures consistent.

 

[pegelli]

I have shot loads of FP4 in the past and now FP4plus. Didn't notice any major differences (my variability between exposure and development is probably bigger). Maybe they added the "plus" when Harman took over Ilford, but there might be slight other changes as well, but for me not enough to notice in practical use.

What is noticable different is Ilford Delta 100 pro, vs. FP4plus, Delta 100 has a slightly finer grain and is also a bit lower contrast, but these changes are still quite small. Same with HP5(plus) vs. Delta 400 pro, There again the Delta 400 is slightly finer grain than HP5, but also slightly lower contrast.

Still between FP4plus/Delta 100 and HP5plus/Delta 400 there is a significant grain difference, much more than between these two different emulsions when developed to the same iso.

I always watch temperature carefully and correct for too high/too low. When you buy ID11 or Microphen you get a temperature correction graph on the inside of the box and I use that religiously. I've always done that so can't tell you how important it is, but looking at the tables/graphs 2 degrees C is almost the same difference in time needed to push for instance Delta 100 to 200 iso, so from that I conclude temperature effects are not negligible.

 

[tribal-warrior]

Thankyou for the detailed info. Someone on another forum was saying that there was a particular Ilford b&w film stock which required very precise temperature control during processing. I can't recall which film it was but I'm sure it wasn't FP4 or HP5. Perhaps it was one of their professional films. Out of curiosity, even if you do get the temperature of the developer correct while you're pouring it into the tank, I guess there's always the chance that the temperature can change again while it's doing it's thing inside the tank. Unavoidable I guess and hopefully not enough cause for concern. I guess most developing times are fairly short so any temperature changes that occur during that time period may not be a big issue. Though are those short developing times still the norm for 4 x 5 inch sheet film? I'd probably be only developing one film sheet at a time. I did watch a youtube video on processing 4 x 5 inch film and it sounded like the fixing, and possibly the stop bath, were unusually long in duration so there could be some temperature fluctuation going on in those cases.

 

[pegelli]

Well, I've never considered stopbath and fixer temperature dependent. Stop bath is just an acid to stop development but doesn't do anything to the film, fixer just dissolves unexposed (and therefore undeveloped) silver halide so as long as it's long enough and all is removed you're fine. If you leave the film in the fixer for hours and hours you might start dissolving a bit of the developed silver, but a little overshoot of 1 or 2 minutes does no harm at all.

In my mind the only piece of development which is time/temperature critical is development.

By coïncidence I developed a film this morning, the solutions after mixing was 19,5 degrees C, however the temperature in the room was 21 (so the whole tank/reel/film etc was slightly warmer than the liquid). After I poured it in and waiting 1 minute the liquid became 20. After 11 min (almost the complete development) I checked again and it was still 20 so I poured out after the prescribed 13 minutes. In this case the temperature remained constant but I've done developing in a cold cellar where the temperature dropped about 1 degree in the course of the development. I then just added half the time for 1 degree lower to compensate for the slight drop.

The temperature / time correction graph you get with the developer seems to be the same for ID11, Microphen and Perceptol and also the same for all films they mention (8 different ones).

Here's an Ilford booklet on their powder developers, lots of interesting details and tables/graphs to help you with this: https://www.ilfordphoto.com/amfile/file/download/file/1829/product/708/

 

[tribal-warrior]

Well, I've never considered stopbath and fixer temperature dependent.

It's been so long that Ive done darkroom work that I'm out of touch with a lot of the fine details. However, there is a youtube video released by Ilford which recommends a temperature of 20 degrees C for the stop bath and fixer (at least for paper prints.)

https://www.youtube.com/watch?v=O31OZgnCoAw&t=109s

Here's an Ilford booklet on their powder developers, lots of interesting details and tables/graphs to help you with this: https://www.ilfordphoto.com/amfile/file/download/file/1829/product/708/

Thankyou. Very comprehensive reading. It sounds like ID-LL will suit me the best since I'm after generally good quality results with no change in film speed. Though I'm a little puzzled by some temperature recommendations on page 9.

The text reads: "PERCEPTOL, ID-11 and MICROPHEN can be used
in the temperature range of 20–24ºC (68–75ºF).
For processing at other temperatures increase the
given development times by 10% for each 1ºC
(2ºF) drop in temperature and decrease the given
development times by 10% for each 1ºC (2ºF)
rise in temperature. "

So with that mind, I'm assuming that temperatures within the range of 20 - 24 degrees is fine and development times should be normal. And that temperatures outside of that range would require an adjustment of the developing times.

However, there is a bit of a contradiction here:

"... if 6 minutes at 20°C/68ºF is
recommended, the time at 23°C/73ºF will be 41/2
minutes..."

23 degrees is within the 20 - 24 degree temperature range but now we're told to make adjustments. And I'm curious what '41/2' minutes means. Surely, it cannot mean 41 and a half minutes as that's a significant jump from 6 minutes.

 

[Oren Grad]

So with that mind, I'm assuming that temperatures within the range of 20 - 24 degrees is fine and development times should be normal. And that temperatures outside of that range would require an adjustment of the developing times.

No, that's incorrect. For a given development time, every change in temperature affects the contrast/density of the resulting negatives. Certainly people can have different preferences with respect to how much of a change is enough to matter. However, a temperature change from 20 to 24C will have a major impact on density and contrast.

The data sheets for Ilford films include a chart that you can use to extrapolate from the times specified for 68F to determine what the times should be at other temperatures. For example, the most recent data sheet for FP4 Plus specifies (page 3) a time of 8 1/2 minutes at 68F in ID-11 stock for FP4 Plus exposed at EI 125. Using the chart on page 4, you can see that, for example, this translates to about 6 minutes at 74F, or, going in the other direction, about 9 minutes at 66F.

 

[pegelli]

It's been so long that Ive done darkroom work that I'm out of touch with a lot of the fine details. However, there is a youtube video released by Ilford which recommends a temperature of 20 degrees C for the stop bath and fixer (at least for paper prints.)

Other than "shocking" the emulsion due to large temperature shocks the 20 degrees C is not critical in my opinion. Obviously it's better to have a constant temperature, but a few degrees up or down isn't going to make a lot of difference

The text reads: "PERCEPTOL, ID-11 and MICROPHEN can be used
in the temperature range of 20–24ºC (68–75ºF).
For processing at other temperatures increase the
given development times by 10% for each 1ºC
(2ºF) drop in temperature and decrease the given
development times by 10% for each 1ºC (2ºF)
rise in temperature. "

So with that mind, I'm assuming that temperatures within the range of 20 - 24 degrees is fine and development times should be normal. And that temperatures outside of that range would require an adjustment of the developing times.

I think your interpretation is not correct, it can be used safely in that range but the times still need adjustment. Look at the graphs on page 4, 12 minutes at 20 degrees C needs to be shortened to 9 minutes at 23 degrees C. If not you're giving it the same development as 16 minutes at 20 degrees C, so that's a considerable ISO push. But the strange thing is that the formula they give is inconsistent with the graphs. However I have always followed the graphs and got consistent results.