Ilford HP5 Plus at a Historical Engine Factory

After getting back into film and starting the Analogue Photography series with the iconic Kodak Tri-X, I turned to its European counterpart for this round — the equally legendary Ilford HP5 Plus. Long favored by press photographers, photojournalists, and enthusiasts who needed a reliable workhorse, HP5 Plus has earned its reputation as a versatile and forgiving black-and-white film.

As several people asked about my gear in previous articles, here it is: I tested this film in a Nikon F80 with Nikon AF-S 50mm f/1.8G, digitised with a Nikon Zf, TTArtisan 100mm/2.8 macro 2X, and JJC film digitizer

For this installment, I chose a location much older than the film stock itself — a historic engine factory that felt like the perfect match: the Pythagoras Hot-Bulb Engine Factory.

High up on the southern hills of the city of Norrtälje, Sweden, stands the Pythagoras Hot-Bulb Engine Factory. Once upon a time, engines were built here and sold all over the world, and the place was alive with the sound of work. Today, the factory remains much as it was — preserved as a living museum.

Hot-bulb engines became popular in the late 19th and early 20th centuries, especially for marine, agricultural, and stationary use for their simplicity, reliability, and fuel flexibility. They could run on almost any low-grade fuel oil (kerosene, crude oil, even animal fat). This was a big advantage in rural or maritime settings where refined fuels weren’t available.

There’s something for everyone to discover here: stories of the people who lived and worked at the factory, machines and engines that still rumble and rattle, business offices with their original furnishings, and workers’ homes from the 1940s complete with kitchen rugs and herb gardens. Children can play and learn in Children’s Pythagoras — a 500-square-meter former test hall. There are also smaller exhibitions to explore and a cozy café in the old forge.

What is now Children’s Pythagoras was once the factory’s old test and packing hall. Back then, it was known as the Wolf Pit — but don’t worry, it had nothing to do with real wolves! The name came from engines that had some defect; these “wolves” were tested here. During testing, power output, fuel consumption, and other performance aspects were measured. Afterward, the engines were packed into large wooden crates and shipped off to customers around the world.

Pythagoras is a genuine factory frozen in time — a place where the early 20th century lingers in the air. The scent of iron and oil greets visitors as they step inside, carrying them back to the era when Sweden was becoming an industrial nation. Every corner feels untouched since the last worker left, as if time itself has paused.

Founded in 1898 in Norrtälje, the Pythagoras Engine Factory quickly grew into the city’s largest workplace. Here, machine tools clanged and engines roared, but it was the hot-bulb engines that earned the company worldwide fame. From this small town, engines traveled across the globe, powering agricultural machinery, fishing boats, and other vehicles.

By the early 1980s, however, the factory faced demolition — until a determined group of enthusiasts stepped in to save it.

In 1992, the engine factory was declared a listed building and transformed into a living museum. Today, it’s preserved and run by the Pythagoras Engine Factory Foundation, with the support of the Pythagoras Vänner association, allowing visitors to step back in time and experience a piece of industrial history.

The factory has remained nearly intact since operations ended in the 1960s. The office still holds its original drawings and archives; the machine hall is filled with engines and tools, waiting as if for the next shift to begin.

Inside, there are drawing offices, business offices, and a separate room for the director. The old Bakelite telephone still rings with someone wanting to order spare parts.

Now, it lives again as a working museum: lathes hum, belt transmissions rattle across the ceiling, and hot-bulb engines thud and vibrate during tours. When the doors swing open, visitors aren’t just entering a museum — they’re stepping straight into history, into a bygone era that still breathes around them.

Pythagoras had offices in several locations over the years. This wing was originally built as a storage room but was converted into an office in the early 1930s and remained in use until the business closed in the 1960s.

Conclusion

This film stock is as versatile and reliable as the Kodak Tri-X I discussed in the previous article. Right off the bat, I’d like to emphasise that I like both, but there are differences — and I prefer one over the other depending on the subject matter. While Tri-X has long been the market leader and favourite in the Americas and other parts of the world, Ilford HP5 — and later HP5 Plus — became the go-to choice in Europe among pros and enthusiasts, from photojournalists and documentary shooters to anyone working with available light — and that’s not without reason.

Both films share that unmistakable classic look, yet their grain structures and tonal qualities set them apart. Some people swear by Tri-X for everything, while others love HP5/HP5 Plus for its subtler character. HP5’s grain gives images a nostalgic texture like Tri-X’s, but it’s softer and its contrast is a bit lower. Personally, I prefer this look for most of my photography — though I still love Tri-X for its coarse grain, deep blacks, and high contrast that give certain subjects a punchy, graphic edge.

Which one do you prefer?

Buy Ilford HP5 Plus on Amazon (Affiliate link)
Kodak Tri-X 400 on Amazon (Affiliate link)

All the pictures in this article come from a single roll of HP5 Plus, shot at ISO 400. They were developed in Rodinal 1+25 and scanned to JPG files by bildskanning.com in Sweden, but I photographed the negatives myself to obtain the raw files and gain more control over the tonal edit. You could also use Kodak HC-110 for similar results: high contrast, excellent sharpness, and distinct grain. If you prefer a good balance of fine grain, sharpness, and tonal range, I would recommend developing the film in Ilford ID-11 or Kodak D76, though. For the finest grain and good sharpness, you can try Ilfotec DD-X, Kodak XTOL, or Adox XT-III.

The pictures you see in this article all come from a single roll of HP5 Plus, shot at ISO 400 and developed by bildskanning.com in Sweden. I digitised them myself, though, and tinted to taste.

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