Oooops. Looks like one of my posts did not make it. I will try again.
I am not sure what the reason is for the desiccant. It is common with commercial lab grade vacuum drying systems---see the example below.
I think I will proceed with the experiment in the new year and will report back my results. There is so much experience with APUG members that I thought it was worth a try to tap into the collective knowledge and see if some one had already had a go at vacuum drying. I do appreciate all your replies and ideas---most grateful for the interest.
I like 135 format, but tend to push its use to an extreme. With a rangefinder camera and optics and the new emulsions (TMAX-2 400), I find it possible to get an extraordinary amount of information content off of a negative.
When I use to scan with my Imacon 343, the dust issues never showed to this extent---but that was at 3200 ppi. Now I am at 6300 ppi with the X1 and its a whole new ball game.
I do occasionally get film back from the lab that 'lucks out' and is nearly dust free, so it is not a scanner issue. But it may be a good idea for me to check reference with a XTOL D&D to make sure it is not a PyroCat issue---though I have seen the problem over multiple batches of developer. Further, I have seen the same trend of problems with tests at different labs, and even with color negatives.
Most grateful for the interest---I will report back when I have done the experiments.
Boy I understand that feeling. In my line of work we usually build *ONE* of whatever it is, then never see another one. Every customer on the planet wants to know why things aren't cheap like TVs are in Wal-Mart. You can't get them to understand that the prototype TV wasn't so cheap, and what they're ask us to quote is really just like a prototype.
Originally Posted by Nicholas Lindan
I'll take one in a plastic box if you've got it.
Pete, you are quite right - pulling a vacuum will boil off the water on your films.
The drying cabinet for a vacuum would effectively need to be a Pressure Vessel - which is a serious piece of Engineering
To pull enough vacuum to dry the film, you would need to reduce the pressure inside the drying cabinet down to only a few Pascals (I can tell you how many if you want to persist with the idea)
However, it will have to be one heck of a drying cabinet - with a hermetically sealed opening and cabinet sides that will each sustain aprox 6 tonnes of load without deformation.
Half inch think steel plate will do the trick for the walls.
No idea who you would talk to about a sealed opening - do you know anyone in the Submarine or Pressure Vessel manufacturing industry?
Alternatively you could try a sealed volume and a Chemical Desiccant Salt arrangement - but I have no idea how you control the chemical dust levels to the levels you require
Or - you could go back to your Lab and ask them about their levels of cleanliness and general house keeping – they obviously can do it, as they meet your standards – if only occasionally
Well, we haven't made one in a plastic box yet. Lets see ... $80,000 for the tooling, $29.99 for the timer.
Originally Posted by michaelbsc
I can share my experience with you because I used to have the exact same problem you describe. I solved it by using a Senrac on-reel dryer. After a quick soak in distilled water with Photo Flo, I dry the film on-reel for 8 min. with warm air, followed by 8 min. of cool air. The negatives are absolutely spotless. However, the film curls. I solve it by winding it against the curl and putting it in a 1 inch tube for a couple of hours. Works great!
The other source of dust is your scanner, and in particular the film holder. If you're using a glass holder, you will have to clean the holder really well.
The other thing that works great is an anti-static film cleaner like this one. It works wonders, at least for me .
I second the advice about humidifiers.
Hope this helps.
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The accumulation of dust on film is a function of time.
Originally Posted by Pete Myers
All things being equal, the dryer the film at start the less
time required. So first eliminate the surface water using the
designed for film eight blade squeegee. A pre or post soak in
alcohol may be possible although I do not know if it would be
compatible with squeegeeing.
I squeegee for fast drying. I find no cabinet needed. If you
try the eight blade be sure it and your film have had a soak
in a weak PhotoFlo solution. Draw it slowly down the full
length of the film. Dan
Back to basics. No extreme measures until you've eliminated the usual suspects.
If your film comes back from other labs with less or no dust issues, your current lab is the likely problem.
Do your films, when processed by other labs, have the same issue? If so, you may be the source of the dust problem. Anti static brush and various measures may help.
I'm going to venture that scanning a 400 speed film at 6400dpi isn't resolving 1000 of specs of dust, but maybe it's the films structure you're seeing. Might be wrong. I'd try asking around in scanner or digital forums to see if they can offer ideas in this direction. Just a thought.
You know, I was thinking along that line as well, there is a limit to scanning, where you start to see the structure of the film itself, which isn't perfect..... Same goes for enlarging, for example a 4x6m image from a 35mm negative will look pretty ugly, same thing from an 8x10 negative will look pretty good.
Originally Posted by GraemeMitchell
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The greatest advance in photography in the last 100 years is not digital, it's odourless stop bath....