Sal Santamaura
Member
....We don't know whether this CineStill "Double XX" is created by Eastman Kodak selling master rolls for 16mm/35mm product to Cinestill, which the latter then has cut and finished as 120 rolls. If so, the resulting product might share physical traits with 120 Ilford Delta 3200, which is cut from 35mm master rolls with thick-for-120 gray-tinted base...
In that case, it'll be interesting to hear how well it feeds in various cameras/backs, considering its much-higher-than-typical base thickness for 120. I suppose those that do well with Delta 3200 will have no problems....Cinestill did tell me directly that this is cut from a master roll of 5222 that they buy directly from Kodak.
On a related note, 120 backs with reverse-curl film paths typically cause a bulge (toward the lens) when acetate base sits on the feed roller for surprisingly little time. My measurements have shown that thickness of the film affects how steeply it ramps up and down to/from maximum bulge, magnitude of which is established by back geometry alone. Thinner bases taper up/down over short distances, while thicker ones do so more gradually. Thus, a greater proportion of the frame is affected by bulging with thick-based films.
Bulging is a non-issue for straight-across film path cameras (including Mamiya TLRs) as well as TLRs that don't bend the film until after exposure, e.g. Minolta Autocord. Those TLRs like the Yashica Mat that bend the film only around a feed roller, rather than under a sensing roller, before exposure are less problematic. The kink they put in acetate film base is away from the lens, and significantly constrained by the pressure plate.
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