Polaroid Type 105

Type 105 was the positive/negative pack-film cousin of the more famous Type 55. Same idea: pull the print, peel the negative away from the pod material, drop it in a sodium sulfite clearing bath, end up with a usable black-and-white negative alongside the print. The difference was format. Type 55 was 4x5 single sheets in the 545 holder. Type 105 was 3.25 by 4.25 inch pack film loaded into a Polaroid 405 holder or a pack-film back on a Mamiya Universal or Polaroid 600SE.

The smaller image size lowered the resolution ceiling, but the negative was still sharp enough to enlarge to 11x14 without grain becoming the limiting factor. ISO 75 daylight kept grain tight, and the pack-film convenience let you shoot ten frames per pack instead of swapping single sheets. For medium-format and press users who wanted a Polaroid proof and a real negative from the same exposure, 105 solved a problem nothing else really did.

Ansel Adams gets the popular association with Type 55, but plenty of working photographers used Type 105 in the same role: location proof and archival negative in one shot, with the pack-film version favored when the camera body forced the smaller format.

Clearing the negative was the part that beginners always under-prepared for. The sodium sulfite bath needed mixing fresh, the negative needed about three minutes of agitation, then a water rinse and a hanging dry. Rush any of it and you got a streaky, milky negative that would not print cleanly.

Format was 3.25 by 4.25 inch pack film in eight or ten frame packs. Type 105 was renamed Type 665 in 1977 as part of Polaroid's Professional Pack Film line, and that successor stayed in production until the pack-film discontinuation in 2008. Freezer stock circulates but pack film deteriorates faster than 4x5 sheets because the pods are exposed to more environmental stress in the pack.

Reciprocity exponent is 1.0. Zone Light Meter treats the metered time as the shot time. A two-second meter reading is a two-second exposure, where conventional ISO 75 panchromatic stocks would need three or four seconds at the same reading.