Konica Infrared 750nm – Experimenting with Expired Infrared Film

A few months ago a professor at the University of Sheffield where I work gave me and some colleagues a couple of boxes of expired film, which were owned by his father. Most of them were black and white, 35mm, and all had expiry dates over 20 years ago but had been kept in the fridge. There were a few boxes of the film featured here, Konica Infrared 750nm, with expiry of 2001. I decided to give it a try over summer, when the light is brightest, in the hope of creating some characteristically infrared landscape images with black skies, white fluffy clouds and white foliage like others’ work I have often admired.

I didn’t have an infrared filter of my own but I was able to borrow a Hoya R72 from my colleague Chris. It was 49mm thread so it fitted my Pentax-M lenses. I loaded the roll into my ME Super with the 28mm f/2.8 attached. First problem: I didn’t know what ISO setting to use! It’s not listed on the box anywhere as one would expect. I re-checked in case I’d missed it, but it was definitely not there. Then I looked in the little instruction book that was in the box, which informed me that the ISO was 32.

The next problem was that I didn’t know how many stops to adjust the exposure by with the IR filter attached. I thought it would be easy to find out online, but it was anything but. I found many definitive answers saying that it was 4 stops, 5 stops, or 10 stops depending on who was advising. So that was not helpful. I thought I had better bracket the exposures, at 4 stops and 10 stops, with nothing in between, because I don’t like wasting film (even if it is free!). This strategy turned out to be counter-productive.

I remembered I needed to adjust the focus for infrared photography. This was easily achieved on my Pentax lens which has a marker for this on the focus scale.

There were some times when I couldn’t really be bothered to set up the tripod and manually calculate the exposures, so I wondered what it would be like to shoot it as a normal b/w film, rather than infrared. This allowed me some handheld shooting, on bright days.

Once processed by AG Photolab, I downloaded the scanned images and I was pleased with some and bemused by others. There were many that were very very grainy and low contrast. The non-IR ones looked great. Here are the negatives.

Obviously from looking at the neg’s, many were grossly overexposed and it was impressive that the lab’s scanner was able to extract any detail at all from these very dense frames. What is reassuring though, is that the film is not fogged at all; impressive for 25+ year old stock.

These five were overexposed and I used my image editor to add contrast:

This one underexposed but saved by image editing:

These few were unfiltered, so look like normal black and white.

This is the only “proper” infrared one which had a decent exposure that allowed for black sky and white foliage. I think this was the only one that I let the camera meter, rather than my own clumsy efforts. I couldn’t see a thing through the viewfinder though, so I’m impressed that it included the objects I wanted, although it’s not a very good picture really.

The pictures I was most impressed by were the non-IR ones. The film gives beautifully rich tones and depth of contrast. I’ll be using this film again even if not with a filter. I don’t really know how to do the IR and it was frustrating to have so many rubbish frames from this roll. If I knew how much visible light the filter was blocking, it would help. I probably would have created more usable frames if I had bracketed 3 exposures per picture rather than 2. Next time I will. I have a few rolls left to try, and after that it is gone forever.

My favourite picture from this roll is the one of the patterns in the old tree trunk, which was photographed unfiltered, even though I would have preferred the top left to be in focus as well as the centre. This lovely Konica film seems to have given the picture a special quality with deep blacks and fine detail across the whole range of tones.

I share my photography on Flickr which you can view here.

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