Shanghai GP3 400

Shanghai GP3 400 is the higher-speed sibling to GP3 100, both manufactured in Shanghai by what is now the Shanggong Shenbei Group on a production line that traces back to 1958. The 35mm version is the recent addition. For most of its existence GP3 lived in 120 only, popular with Chinese medium-format shooters and a small Western following. The 35mm rolls started showing up around 2019, the 400 speed following soon after.

The grain sits on the heavier end of the budget 400 class. Side by side with Kentmere 400 and Fomapan 400, the GP3 grain reads coarser and a little less tidy than either. Some shooters love that texture; some find it muddy. The contrast tends to run high out of the box, more like Fomapan 400 in Rodinal than the gentler curve of Kentmere. Sharpness is decent but not in the same league as TMax 400 or Delta 400.

One quirk worth knowing about: the base curls badly after fixing and washing. Shanghai GP3 in any speed comes off the reel with enough memory that scanning flat without a glass holder is genuinely difficult. Press the strips between heavy books overnight before you scan or you will fight Newton rings and lens fall-off in every frame.

For developer choice, the film responds well to D-76 at 1:1 if you want to tame the contrast, or to Rodinal 1:50 if you want to lean into the grain. Pushing to 800 is possible in Microphen or Xtol, but the shadows go thin fast. Treat box speed as the honest rating.

Available in 35mm 36 exposure, 120 roll, and 4x5 sheet, plus a 30.5m bulk roll for hand-loaders. The pricing has crept upward but still beats Ilford and Kodak by a noticeable margin in most markets.

The reciprocity exponent is 1.31. Zone Light Meter applies the correction past one second. A metered 30-second exposure works out to roughly 90 seconds at the negative, so for indoor available-light at small apertures the correction comes up more often than you might expect at ISO 400.