HP5+ @ISO 100,000, Film Prices & Private Beta

2025 is off to a fast start with an outrageous film experiment.

Late last year, I posted about making sharper photos and editing film scans. This month, I tossed all of that out the window to push (and pull) one of the world’s most popular black-and-white emulsions beyond anything anyone has ever done.

As for next month, there’s a new app that’s been in development for over three years that I’d like to run by interested GOLD members. Plus, a note about film prices in 2025.

In this newsletter: HP5+ @ ISO 100,000. Ilford HP5+ @ ISO 3. Private app beta. Next month on Analog.Cafe. Support this blog & get premium features with GOLD memberships!

HP5+ @ ISO 100,000.

For the longest time, photochemistry was a difficult medium to use because of its low sensitivity to light. There were no light meters in the 1800s, and the early methods of capturing photos, daguerreotypes, had a sensitivity equivalent of about 0.05-0.005 ISO¹².

My grandparents used a much easier medium, flexible film, that was also a lot more sensitive. There was a lot of variety in the early and mid-century; I’d guess that ISO 25 was standard or average. This significantly higher sensitivity meant that we could take pictures of action without a tripod with fast lenses.

My parents had and have access to more, faster films that often went up to ISO 400. Meanwhile, relatively recent emulsions went up to ISO 1600 for colour (Fujicolor Natura) and ISO 3200 for black-and-white (Ilford Delta and Kodak T-Max).

Digital cameras can even be more sensitive than that — but film has one advantage sensors do not: it can be pushed.

One of the most recommended films to push is Ilford HP5+, an emulsion first introduced in 1879. It’s regularly shot at EI 1600, but as I stared at the remainder of my bulk roll from trying to develop in weed, blood, and Epi-Pen, I wondered if it could be pushed beyond all previous public attempts: ISO 100,000.

This article, “Pushing Ilford HP5+ to ISO 100,000,” examines the challenges of shooting and developing eight stops beyond rated sensitivity. You can see one of the results of this experiment above, which took a special developer, some messing around in Google Sheets, and a long time twirling Paterson tank. But not all came out looking like that; one image of my images was so intensely altered by the process it turned into a positive!

¹ — Estimate provided by Jason Greenberg Motamedi.

² — John Hurlock corroborated the above with his paper, “Unlocking the Secret: Hyper-sensitizing Daguerreotypes with Light.”

Ilford HP5+ @ ISO 3.

Would you think I’d push HP5+ to ISO 100,000 without trying to pull it more than anyone has tried before? Of course not. Here’s the article with samples, development times, and discussion about that: “Pulling Ilford HP5+ to ISO 3.”

Private app beta.

There’s one more thing I’ve been working on during this and the past month. It’s an app that I’ve been using and testing for three years — the most challenging piece of software I built. But it’s not yet ready for the general public.

I would like to keep it under wraps for a little longer, which is why everything below is visible only to the GOLD members.