There was some chat on Facebook the other evening about Lomography Purple film and why it is rated between 100 – 400 ASA rather than being fixed (it has no DX code for example).
The way I always see it is the chemists in the labs of the film companies work hard and are usually confident that a film will behave reliably at a particular rating (bearing in mind age and how it is developed and printed too).
So you can expect Kodak TMax at 100ASA to behave a certain way and you can rely on consistent results if you treat it consistently. This is how professional photographers could do their thing back in the days before digital.
I used to work with a physicist and he liked cameras as much as me. To him, the camera and film were scientific instruments, and could be controlled with precision according to their parameters; focal length of lenses, apertures, speed of the films.
I was (and still am) a bit more “turn it up to ten and see what happens”, and in a similar vein Lomography has always been about “try this and see what you get, you might like it!” The “Lomo Purple” stuff is so wacky and does interesting things according to how many photons you feed it and I think they may well have wanted to just encourage that flexibility and expressiveness rather than prescribe a look that a professional photographer will dial in and use perpetually.
I shot two rolls in 2018 having picked them up from the Lomography stand at the Photography Show. I used a Ricoh R1 which defaults to 100asa when there’s no DX, and it worked great outdoors in nice bright weather and even great in the low light of the Elbe Tunnel.
Composition aside, there wasn’t a disappointing shot on either roll that I tried, but equally I would have struggled to replicate stuff.
It’s tremendous fun, but you can only really be certain it isn’t B&W, standard colour or xpro and it’s basically an “unfaithful” film. The grooviest shot was this field of oilseed rape which came out purple instead of yellow.
I took this iphone shot at the same time for reference and a reminder that it is “unfaithful”.