still fighting defects on film

[Dwig]

One common source of fine white particles on dried film is the use of overly concentrated Photo-Flo.

Kodak Photo-Flo 200 should be diluted 1:200 with water. The label's instructions referencing "a capfull..." are dubious. For decades the newer bottles used a new plastic cap that was at least twice as large are the original metal cap but the instructions didn't change. Overly concentrated Photo-Flo will leave residue in the form of white crystals in the film emulsion that can't be cleaned.

In general, Photo-Flo should be diluted as much as possible as long as the water flows off in sheets rather than forming droplets on the film's surface.

 

[mbisc]

In general, Photo-Flo should be diluted as much as possible as long as the water flows off in sheets rather than forming droplets on the film's surface.

1ml per 20 oz of distilled water is a good starting point

 

[emraphoto]

i love this place

 

[zauhar]

Michael, try a 5ml transfer pipette for introducing photoflo. I just leave it in the bottle and pull up maybe 1 or 2 ml, which seems completely adequate.

Maybe you want to make a drying cabinet of your own? I made one from an Ikea tall utility cabinet, cut a hole at the top for a duct fan, and put a HEPA filter over the air intake. It doesn't provide huge air flow, but is enough to keep positive pressure in the cabinet, and seems effective at keeping out dust.

Randy

 

[JoeV]

In my home made film drying cabinet I use a HEPA-filtered computer fan and 100 watt incandescent lamp. The heat helps a lot in fast drying.

I suspect the lamp's heat might reduce particles on the film, too. I say this because, under vacuum conditions, particles migrate toward a cold surface (this was proved in tests at Sandia Labs, years ago, in a study for the semiconductor industry). Now, my film drying cabinet is not under vacuum, but there might remain some effect of particles migrating toward cold surfaces.

Static is equally a culprit. My cabinet is made from metal and is grounded, as is the film, hanging via metal Bulldog clips from a metal wire attached to the cabinet.

I would ditto others' recommendations about distilled water and minimal rinse aid.

~Joe

PS: I get very clean film now, even though the cabinet is located in my dusty garage and the humidity here in Albuquerque can often be single-digit.