Reciprocity Loss, Rating film & developing

[Joel DG]

Looking for suggestions on shooting and developing a roll of 35mm FP4+ that will be used entirely for long exposures. I will shoot as suggested by Ilford to account for reciprocity loss, which in the case of FP4+ is metered time to the 1.26th. A few people have suggested shooting at box speed and pulling 1/3rd. Seems odd to me to have a standard pull amount rather than one that varies based on the exposure length. Thoughts? Anyone experienced with this?

 

[Mainecoonmaniac]

If you have an iphone, this app works great.

https://itunes.apple.com/us/app/reciprocity-timer/id459691262?mt=8

If you're not particularly stuck on using FP4, I'd use Fuji Acros 100 instead.

 

[Joel DG]

Thanks for the input. I think I'll pull 1/3rd, and vary the shots from a few seconds to a few minutes and see what happens.

 

[Joel DG]

If you're not particularly stuck on using FP4, I'd use Fuji Acros 100 instead.[/QUOTE]

Why Acros?

 

[Svenedin]

I’ve used Delta 100 for long exposures using the Ilford calculations and it has worked well so see no reason why FP4+ shouldn’t do well too (the reciprocity factor is the same). My exposures were in the range 5 to 15 minutes. With exposures that long I wasnt too precise about it. I’ve also had good results with HP5+. Make sure you use a lens hood. I didn’t at the start and got some annoying glare/flare from stray light. I’d always use a hood in the sun, hadn’t occurred to me that it was important at night.

 

[RalphLambrecht]

Looking for suggestions on shooting and developing a roll of 35mm FP4+ that will be used entirely for long exposures. I will shoot as suggested by Ilford to account for reciprocity loss, which in the case of FP4+ is metered time to the 1.26th. A few people have suggested shooting at box speed and pulling 1/3rd. Seems odd to me to have a standard pull amount rather than one that varies based on the exposure length. Thoughts? Anyone experienced with this?

I'd follow the Ilford suggestions buttery to make up for the exposure difference by opening the aperture not extending the time otherwise, you get deeper and deeper into low-intensity reciprocity failure.

 

[Svenedin]

Here’s one of mine that’s quite a short exposure, 25 seconds, f8, HP5+ and another much longer exposure, 10 minutes, f32, also HP5+. In the second shot a Cross-Channel ferry went by (it was intended that the ferry was in the shot).

Moonlit Old Portsmouth (graded paper)

• Svenedin
• Oct 21, 2016
• 3

The moon over Old Portsmouth 18/10/2016. Low tide at slack water. Taken from HMS Dolphin. Camera...

Portsmouth Long Exposure #2

• Svenedin
• Sep 9, 2017
• 4

Another shot testing the Ilford film reciprocity numbers. Again no tripod so not nicely...

 

[Joel DG]

Here’s one of mine that’s quite a short exposure, 25 seconds, f8, HP5+ and another much longer exposure, 10 minutes, also HP5+

Nice stuff.

 

[Mainecoonmaniac]

If you're not particularly stuck on using FP4, I'd use Fuji Acros 100 instead.

Why Acros?[/QUOTE]
Because Acros has minimal reciprocity failure up to a certain point. But the best compared to other films. I had to use the film when I was shooting the unlit interiors of Ankor Wat in Cambodia.

http://istillshootfilm.org/post/105013947805/what-is-reciprocity-failure-and-how-to-correct-it

 

[Svenedin]

Thank you. Just to illustrate that it's worth a go and the results can be interesting. If the Ilford reciprocity calculation is used it's likely that usable shots can be obtained. It helps to bracket the exposures but this can mean a long time is spent in the field! It's fun as the results are a bit unpredictable.