Ilford HP5+

HP5+ is what Tri-X would be if it had been engineered for pushing first and box speed second. Ilford's claim is that HP5+ holds usable shadow detail at 1600 with normal development time bumps; in practice photographers regularly push it to 3200 with Microphen and still get printable negatives. Plenty of working photographers push HP5+ to 1600 in Microphen for street and reportage work where the alternative is no shot at all. The film tolerates the latitude swings that come with mixed light and harsh strobe, which is why so many documentary and editorial shooters keep a brick of it in the fridge.

Compared with Tri-X the grain is slightly larger and the curve is straighter. Mid-tones land where you put them, which is why Zone System shooters trust it. The shadows resist blocking up even when you underexpose by a stop, and the highlights take a long time to peak. That makes it forgiving in a way Tri-X is not.

Ilford makes it in 35mm, 120, and sheet sizes from 4x5 through 8x10. The 120 is particularly clean; the 35mm grain is more pronounced and more loved for it.

The reciprocity exponent of 1.31 matches Tri-X almost exactly, which is convenient if you switch between them. A 30-second meter reading becomes about 90 seconds at the negative; Zone Light Meter folds the correction in past the one-second threshold.

One catch: HP5+ has a slight warm scan tendency that some labs correct out. If you want a cooler look, ask for a flat scan and tune at home.