Dear Dave Bias,
i know you´re short on time, but i think i´m having an important point here - it´s about sheet film, but don´t worry i won´t ask you anything which allready has been answered. As i´m taking some of your time anyway, i also want to give you the "emotional part":
I´m not a backer, but analog film and foto was and is very important to me, but during the last years a lot of things went down in my life - and seeing Fuji pull out of movie film, Kodak stopping Ektachrome ect. - i really lost a lot of hope. But when Ferrania came along and showed its passion and will to save a part of analog film production, that gave me some hope back. Though you had to struggle a lot and take obstacles which sometimes seemed insurmountable you worked on - and that really was good for me to see.
I don´t want to get too deep and i know that it can sound weird to outstanding persons who arn´t into analog film (and to persons who are into analog film), but seeing you guys holding up just helped me. As there seems to be an analogy between Ferrania and me, my life isn´t as down as it was several years ago, but just like Ferranias factory isn´t at full capability right now so am i - but its getting better.
Anyway i´m here to "talk business" and that´s my point:
Consider to put sheet film on
ACETATE base, not PET (plastic, synthetic material; in movie film synthetic base is called PET).
As far as i know all sheet film nowadays is put on PET-base, which creates a huge problem as PET can pass and create static charge. As nowadays nearly every film holder is made of plastics, which also do create static charge, sheet film on PET base nearly inevitable gets static charge, attracts dust and gives you problems during printing. I researched the net and found some threads discussing this problem and sollutions, but i´ll give you a summary first:
To avoid dust on PET-sheet film some users do:
-clean the holders with antistatic means, like brushes, cloths ect. and lay the holders in their bathroom
-the bathroom has to be cleaned thorough before, including walls, floor and ceiling if possible
-then they run the shower with hot water for several minutes to create steam
-the steam is meant to clean the air by water molecules attaching to the dust in the air and sinking it to the ground
-and high humidity also is able to reduce static charge on plastic items, therefore the holders are placed in the bath
during the steam
-when the steam has set they darken the bath and put the sheet film into the holders, but they push each sheet slowly
only, to aviod buildup of static charge, same goes for dark slides, only move them slowly
-they put each loaded holder into an antisatic ziplog bag, so friction during transport won´t creat static charge
-two loaded holders allready in individual antistatic bags are put into a bigger antistatic ziplog bag and five pairs of
holders again are put into an even bigger antistatic ziplog bag
-then they clean the bellows of the camera with a vacuum cleaner, as dust in the bellows might be attracted by static
charge of the sheet film and get on the film before/during/after exposure
-these antistatic ziplog bags themselfes are made of plastic, which usually creates static charge by friction, but is
covered with a substance which at least stops static buildup; but i don´t know whether this antistatic bags are able to
reduce static charge of a film holder. Anyway the antistatic characteristic of those bags only last for about 6 months -
whether you use them or not - so you can´t buy bulk or use them for years; no you have to buy new ones every 6 month
and discard all old ones
-when the LF-camera is set up one has to be careful not to let dust inside the bellows while changing a lens or
attaching the film holder
-the dark slides need to be pulled out and pushed in slowly only to reduce buildup of static charge
-for transport home the holders need to go back into the antistatic bags as still dust can be attracted to the sheet film
which may be problematic during developement - especially on stand developement as the dust just not might go off
the emulsion side and produce "holes" in developement
-they use an antistatic-gun to zip the holders before loading, before attaching them to the camera, before putting them
back into the ziplock bags ect.
All this methods don´t guarantee dust-free negatives so still dust has to be spotted during printing. If the neg is scanned it can be done digital, which is easier, but if you want to print analog you´re again having some problems:
-dust being on the film during exposure/developement will print black
-as there is no white paint for prints you need to take a rasor blade and scrape off the black dust-shapes on the print
-you need to mix the correct paint (black to grey on B&W) and paint the scraped area
-but because the emulsion is scraped off the printing paper on that spot, the paint will blead into the paper making it
hard to paint the scraped spot correct
-to avoid the scraping of the print you need to take a special red paint and put it on the negativ itself, where the dust
was during exposure/developement
-now the dust will print white and then you can paint the white spot on the print without needing to scrape
Here some links on the topic:
https://www.photo.net/discuss/threads/4x5-dusty-film.420760/
https://www.photo.net/discuss/threads/dust.55609/
https://www.photo.net/discuss/threads/dust-marks-on-4x5.30089/
http://www.largeformatphotography.info/forum/archive/index.php/t-27897.html
https://davidhoulder.com/photography/dust-on-4x5
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As you can see dust can be a hell of a problem and a hell of work to
REDUCE, not to avoid it completely - and the key is the film base. I have bought some old holders with some really old sheet film inside. They´re thicker than the modern sheet films and they don´t pass or buildup static charge. I put a PET-sheet inside the holder, opened and closed the dark slide several times to built up static charge and strewed a bit dust on the emulsion side of the sheet. The dust was held by static charge so bad that i had to place my mouth an inch away from the dust and blow my lungs out to blow some of the dust off - but not all!!!
While the old sheet film having acetate base didn´t attract the dust and a little breeze was enough to remove ALL of the dust from the emulsion - though i again moved the dark slide several times to get static charge on the holder.
One also can compare modern sheet film to 135 or 120, as 135 or 120 usually have acetate base. There will be no dust attraction with acetate-base film even if its held by a plastic-part which has static charge.
Off course the film holders still should be clean, but without dust-attraction by static charge due to PET-base its waaaaaaaaaay easier to get rid of dust on sheet film.
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I assume that there are technical reasons why every (other) manufacturer today puts sheet film on PET-base and that´s why i´m not sending you an email but posting it here - as some other users on this forum might have some insight on this topic.
But if you were able to put P30 (and later chrome) onto acetate-base, if it makes sense technically and in production, this sheet film would be an enormous relief for LF-shooters. It would fill a biiiiiiig gap in the market - and move some into LF-shooting at all, as i`m not eager to go through all of this hassle just for some LF-negs. I was thinking about it, but i´ll only do LF when there is a sheet film on acetate-base out there - and i guess a lot of others think alike.
I know there still is some time till you just can start to think about producing sheet film, but that´s why i´m telling you now about this topic; maybe you´ll find a free minute to ask your experts at Film Ferrania to consider sheet film on acetate-base. If it should be possible don´t forgett to print it on the box, in capitals like: ACETATE BASE - NO DUST ATTRACTION.
Thank you very much for your time and keeping my fingers crossed for Film Ferrania,
H. Callahan