Harry Callahan
Member
@jonasfi and BAC1967:
Thank you very much for your tips, i might try some of these - but as said i only get dust attration with PET, no problems with acetate.
It seems logical at first that sheet film gets more handling before exposure, but i don´t think that´s the cause for sheet having more dust attraction. On one hand films like 135 and 120 do get spooled through the camera and there is friction, especially because there are pressure plates in the cameras pressing the film to the gate. So a 135 having 36 exposures might get even more friction than a single sheet being put into a holder- and sheet film holders usually don´t have pressure plates. On the other hand (reasonable) 135- and 120-cameras are made of metal, pressure plate, film gate ect., so there is no plastic having contact to the film (ok, the core onto which the film is spooled often is made of plastic. But i doubt that there is much friction when this core is turned - at least no as much friction like when a dark slide from a sheet film holder is pulled out). But plastic is what creates static charge by friction and plastic can pass an existing amount of static charge - and that´s exactly what´s happening with sheet film holders. Sheet film holders usually are made of plastic, they do accumulate static charge and they create static charge when the dark slide is pulled out and pushed in or when the holder is transported in a camera-bag - and all this static charge is passed onto the sheet film because the rails holding the sheet also are made of plastic.
Which is what my test seems to confirm. Both sheets, acetate and PE, got the same amount of handling when i loaded them into my holder, but the PE-sheet attracted dust like hell, while the acetate-sheet didn´t. The static charge on the holder couldn´t affect the acetate sheet - and i charged the holder intentionally.
I actually was thinking of attaching a kind of "ground wire" to each holder, so the static charge could be released... but how often do you have a ground to attach the wire to when you´re out shooting... i mean you had to release the static charge before exposure because during transport the holders do get some friction in the camera-bag... its cursed.
Maybe Ferrania could get this antistatic coating cmacd123 is reffering to onto their sheet films.
Thank you very much for your tips, i might try some of these - but as said i only get dust attration with PET, no problems with acetate.
From what I can tell, by the late 90s, only Agfa RSX100 & some Fuji transparency films were still on triacetate in sheet form - Kodak seem to have been entirely on polyester base for BW neg, colour neg & transparency by then. That said, the colour materials may have benefited from more up-to-date anti-static treatment/ coating than the BW materials at that time. It should also be pointed out that triacetate can also become statically charged, but because you're handling it (in 135 or 120 form) much less before exposure there's less chance of attracting dust. Low humidity, clothing choices & flooring/ building materials can all cause static to build up. Treating sheet film holders with anti-static cloths/ brushes etc on a regular basis is a very good idea in general. For that matter, 35mm/ 70mm cinema projectors - which largely run polyester base stock - have an in-line anti-static system before the gate.
It seems logical at first that sheet film gets more handling before exposure, but i don´t think that´s the cause for sheet having more dust attraction. On one hand films like 135 and 120 do get spooled through the camera and there is friction, especially because there are pressure plates in the cameras pressing the film to the gate. So a 135 having 36 exposures might get even more friction than a single sheet being put into a holder- and sheet film holders usually don´t have pressure plates. On the other hand (reasonable) 135- and 120-cameras are made of metal, pressure plate, film gate ect., so there is no plastic having contact to the film (ok, the core onto which the film is spooled often is made of plastic. But i doubt that there is much friction when this core is turned - at least no as much friction like when a dark slide from a sheet film holder is pulled out). But plastic is what creates static charge by friction and plastic can pass an existing amount of static charge - and that´s exactly what´s happening with sheet film holders. Sheet film holders usually are made of plastic, they do accumulate static charge and they create static charge when the dark slide is pulled out and pushed in or when the holder is transported in a camera-bag - and all this static charge is passed onto the sheet film because the rails holding the sheet also are made of plastic.
Which is what my test seems to confirm. Both sheets, acetate and PE, got the same amount of handling when i loaded them into my holder, but the PE-sheet attracted dust like hell, while the acetate-sheet didn´t. The static charge on the holder couldn´t affect the acetate sheet - and i charged the holder intentionally.
I actually was thinking of attaching a kind of "ground wire" to each holder, so the static charge could be released... but how often do you have a ground to attach the wire to when you´re out shooting... i mean you had to release the static charge before exposure because during transport the holders do get some friction in the camera-bag... its cursed.
Maybe Ferrania could get this antistatic coating cmacd123 is reffering to onto their sheet films.