Ilford N5.31 Film

**byronfry** · 16-Jun-2011, 18:03

I was just given a box of old Ilford sheet film called N5.31 Fine Grain Ordinary Base 5/1000. It expired in 1987. I found through google that it's an orthochromatic film rated at around 0.1-0.6 asa.

I'd like to experiment with it. Does anyone have any idea whether I can develop this myself with standard chemicals?

Thanks!

**Jay DeFehr** · 16-Jun-2011, 22:14

It's likely to be high contrast film, and produce a high contrast negative when developed with standard developers. I'd try a low contrast developer- my own- but there are others, intended to produce pictorial gradation from document-type films. TD-3, Technidol, Neofin Doku, etc.

**EdWorkman** · 17-Jun-2011, 11:14

What Jay said, with a comment.
You say exp 1987, so the inherent high contrast and speed are probably affected by age to lower both. A typical developer might make the contrast about right. If the film was fresh Jay's suggestions would be your only hope.

**byronfry** · 17-Jun-2011, 20:21

Thanks for the help! I received an email from someone on another forum. I'll paste it here for the record:

N5-31 is a slow film made for tasks like B'W copying of toned subjects, like photographs.

N = non-colour-sensitive, meaning sensitive to blue light only, not green or red, so can be handled under a DIM yellow safelight like the one for B'W bromide printing. Even so, open the box under red light, or total darkness, if you do not have the right kind of safelight.. (Ilford 902). If you do have the right safelight, work in your own shadow so the minimum of light strikes the emulsion surface..

5 = the film base is 5 x 1/1000" thick (before we metricated, this would be called "five-thou")

31 = emulsion type 31, meaning slow, with a very long straight line section to its characteristic curve. This makes it ideal for copying.

If you use N5-31 for general outdoor photography, you will get the kind of result the very early photographers got... black foliage, very dark grass, and people with blue eyes having no irises. Basically, only blue light registers, which means the blue of the sky comes out the same white as the clouds.

Your film is going to be a bit stale, I'm afraid.... which means it will have lost film speed. Instead of being 3-ISO I suggest you re-rate the film at 1.5-ISO or do test exposures.... Yes! Three ISO, reducing to One-point-five ISO. In artificial (incandescent) light there is less blue, so exposures may need to be 4 or f5 times longer to compensate. Hey! I did say it was SLOW film!

Any standard B'W film developer will do...

... suggested... ID11 or D76 for 3¼ minutes @ 68°F (20°C) Continuous agitation rocking in a shallow dish

... although you may find it can use a bit of extra development because it is a soft-working film and past its date... perhaps 20-50% extra dev time..[????]