Using tray chemistry in roller-transport machinegreenspun.com : LUSENET : B&W Photo - Printing & Finishing : One Thread
I have Thermaphot ACP302 roller transport machine that I use for RA-4 color prints but I also want to use it for B&W RC papers. However dedicated chemistry for roller-transport machines from Kodak or Ilford are not available for me.
Can I use tray chemistry for that purpose? Options are 45 or 32 sec development/fixing times and any temperature up to 40C. I see almost any chemistry requires halfing processing time by each 7C increase in temperature. So if I take 20+7+7 = 34C and 32 sec development/fix this should be about equal to 2min dev/fix at 20C.
Any known adverse effect of higher temperatures? Possibly machine-oriented chemistry contains more anti-oxidant agents but I don't care as I am not planning continuous operation as minilab. Just few days session with fresh solutions.
I am also skipping stop bath but paper passes effective squeege between developer and fixer. Washing and drying is manual.
Has anybody tried that?
-- Leo Bodnar (firstname.lastname@example.org), May 28, 2001
This might be a question best asked of Wing-Lynch, who distribute Thermaphot in the US (if thats where you are). I know that some developers intended for machines contain sequestering agents and the like, for example-whether you can get by without them I will not venture to say. I guess I wouldnt risk the health of a multi-thousand dollar piece of equipmennt by taking advice from people on a message board
-- Wayne (email@example.com), May 28, 2001.
Wayne, Thermaphot ACP 302 is impossible to break! I have purchased it second hand (still have mixed feeling about its construction - it looks very much like a kit put together by good hobbyist, you know). It is very simple and robust. It also has nothing to afraid from chemicals side unless they eat into plastic or stainless steel. I would not worry about the machine.
-- Leo Bodnar (firstname.lastname@example.org), May 29, 2001.
"Wayne, Thermaphot ACP 302 is impossible to break!"
I think the problem from not having the sequestering agent is that silver will deposit and sludge things up. It wont break, but it might be a PIA. This is just my guess-I dont have first-hand experience with it
-- Wayne (email@example.com), May 30, 2001.
Leo...I know it's a couple of months since you asked this, maybe you've gotten an answer already...but anyways, I use an old converted EP2 RCP20 (Durst/Thermaphot) for running b&w rc prints at RA4 temps...it works out to be around 78-80 degrees or so, and 45' minutes in each bath. You can't regulate the speed on the RCP models, but you can adjust the temp...so you can back off on the temp if you start to get fogged highlights...or turn it up to get a better D-max...I run ethol LPD mixed 1:1 as my developer, and Kodak Rapid Fix mixed to film strength, no hardener. I mix up a dilute stop bath for the small tank in between. You can replenish LPD with straight stock solution at the rate of 10-15 oz. per every 45 8x10s...I leave the chemistry in the machine for up to a week, at which point, I dump it all, and do a couple of clean out cycles, and wash the racks & set it back up again...this is all in my home darkroom, at work I use an Ilford 2150 and have approached the Thermaphot in the same manner...I've been doing this for almost 2 years now and have had no problems, it's a rugged little processor, and I imagine the newer models would be as well....although, as a disclaimer, all this is with the old model, which incidentally, neither Wing Lynch, or Thermaphot still support.
I wouldn't worry too much about the stop bath, the 2150 just dilutes it's dev/fix at about a 1:4 ratio. The prints go from the dev to the fix tank, but are very effectively squeegeed in the process. LPD is also made for machine processing as well, and Ethol has a tech sheet for this if you're interested....
-- DK Thompson (Kthompson@moh.dcr.state.nc.us), July 10, 2001.