Polaroid SX-70 B&W

The black-and-white SX-70 emulsion is, in my experience, the most consistent of the current Polaroid lineup. It does not have the color-shift variables that complicate the color versions, and the high-contrast rendering that looks harsh in the color B&W emulsions actually suits the SX-70's optical character. The camera lens is not a technical instrument. It is designed for close focus and pleasant bokeh, not for edge-to-edge sharpness. The B&W emulsion works with that.

ISO 160 means you are not shooting this indoors in available light without either the SX-70 flash bar or serious overexposure. The original SX-70 cameras have a flash mount on top for the disposable Flashbar units, which are no longer made. Aftermarket flash triggers exist, and the Polaroid Flash Bar 2 reissue appeared briefly. More practically, the later SLR 680 and 690 bodies incorporated a built-in electronic flash, though those cameras shoot 600 film rather than SX-70.

Tonal response is high contrast, similar to the 600 B&W but with a slightly different midtone curve because the emulsion chemistry has been tuned for the slower ISO. Highlights compress quickly. Shadow detail is limited. This is not a stock you choose when you need to see into a shadow area. It is a stock you choose when the graphic simplicity of strong blacks and clean highlights is the point.

Reciprocity exponent is 1.0, and Zone Light Meter applies the calculation past one second. The SX-70 camera body can expose up to about 14 seconds in very dim light, so there are real situations where the reciprocity correction matters. Development is slow in cool conditions; the same 15-minute patience rule applies.