Open tray RA-4 developing: how serious is prolonged air exposure?

Dino Joe · Jun 7, 2020

Hello, everyone! I recently purchased a complete darkroom set that contained everything needed for both open tray and drum development. I would like to use the Unicolor print drum, but it leaks just enough for it not to be worth using it. I have thus been doing open tray development. However, I read from the chemical instructions that prolonged exposure to air will cause the chemicals to deteriorate. How serious of an effect does air exposure have on the chemicals? If it's substantial, then I'll likely invest in a new drum and pray that it doesn't leak; I'm very environmentally minded and would hate to go through more chemicals than I have to. Otherwise, the open tray process has been fine. I'm still a novice to print development and I like taking my time in the darkroom, so I feel rushed every time I go in in my effort to minimize the effect on the chemicals.

Should I go for buying a new tank? Or is air exposure not too large of an issue?

pentaxuser · Jun 7, 2020

From what others have written I have inferred that open trays are fine for one long session so the developer is unaffected for maybe 24 hours but beyond one day it might be adversely affected at least to an extent by the next day. Frankly I cannot recall if this was ever specifically covered as a point of information and it may be that, as in general terms, open trays are only good for the day on which they are used no-one ever felt the need to mention it as the assumption was that everyone know about the one day rule

Maybe now that you have raised the issue open-tray users will reply. I'd be interested, especially if there is a way to extent this such as covering the trays after use with "cling film" that is used to cover food

pentaxuser

Donald Qualls · Jun 7, 2020

One way to improve your situation re: open tray processing might be to invest in (or build) a slot processor. These minimize the exposure of chemistry to the air, first by turning the conventional tray up on its long edge, so instead of, say, a 9x11 inch surface area exposed to process 8x10, it's only 1x11 -- and second, most of them have floating lids that fit in the slots so each slot can be closed off in a matter of seconds, nearly stopping oxidation between actual printing sessions. Some have water bath shells to aid in temperature maintenance, but from my reading many workers use RA-4 at room temperature.

The device itself is pretty simple -- a fairly narrow vertical tank made from plastic (acrylic or polycarbonate work well), with dividers to make the number of slots you need (just two for RA-4, but most have three or four so they can be more versatile -- C-41 sheet film, for instance, or even E-6), and a drain cock at the bottom of each section so you don't mingle your developer and blix etc. when you need to empty the processor. Agitation is by lifting and dropping the sheet, instead of rocking the tray.

mshchem · Jun 7, 2020

A very easy trick with RA-4 .Get a couple wide mouth jars, like a pickle jar, something you can find in the dark. Use one tray, pour in and out in the dark. If you have a water bath you can keep the jars warm.

jamesaz · Jun 8, 2020

I did some last summer in trays. I just kept up with the replenishment, kept the temperature stable with a water bath and covered the trays with sheets of acrylic when I was thru for the day, mostly to hinder evaporation. It was one of the 2 liter kits if I remember correctly. Anyway, I got 2 full days out of it. Maybe 40 or so 8x10 prints plus tests. Good luck.

koraks · Jun 8, 2020

In my experience, with a seasoned (ie replenished) developer, color shifts become apparent within about 2 hours without additional replenishment. Replenishment can be used to keep the developer performing well. I also found that pH is a good indicator of the on-spec performance of RA4 developer used this way. The pH tends to drift downward as the developer ages (oxidizes), resulting in a shift towards magenta and loss of solid blacks. My personal approach is to measure pH at the start of a session and replenish the developer to the point of pH being on specification (which can be found in the datasheet of the chemistry), and then monitor pH periodically and replenish as needed to keep the pH on target. After a session, the developer goes into a full bottle with no air on top. I've been using the same batch of developer for about 2 years now, but of course over that period it has been essentially replaced many times through replenishment. I do not use heated trays or water baths and simply use the chemistry at room temperature.

Note that this is just one way of doing it; there are several approaches that work. Important choices are:
* Use of one-shot vs. replenished chemistry
* Development in trays, rotary tubes or a roller transport processor
* Room temperature vs. higher temperatures
* Replenishment (if employed) based on processed paper volume or based on pH monitoring
There are a few possible combinations of the choices above that may work well. Hence the variety in opinions you'll see on here in how people believe it 'should' be done. My conclusion is that there are a few ways in which you can get consistently good results and it's not so much a matter of 'tubes being better than trays' etc.

Bikerider · Jun 8, 2020

pentaxuser said:
From what others have written I have inferred that open trays are fine for one long session so the developer is unaffected for maybe 24 hours but beyond one day it might be adversely affected at least to an extent by the next day. Frankly I cannot recall if this was ever specifically covered as a point of information and it may be that, as in general terms, open trays are only good for the day on which they are used no-one ever felt the need to mention it as the assumption was that everyone know about the one day rule

Maybe now that you have raised the issue open-tray users will reply. I'd be interested, especially if there is a way to extent this such as covering the trays after use with "cling film" that is used to cover food

pentaxuser

You may have seen my posts about RA4 developing and while I agree with your comments about the deterioration of the developer over a 24 hour period (I would have said less than 24 but never mind). I use a NOVA processor and 'Clingfilm' does slow things down over an extended period, but for covering a whole dish I would say is impractical. The plastic does allow some air leakage over days but the main reason I use it is that it does stop evaporation of the water from the developer/stop/fixer baths. Also depending on what size of dish that will be used and the width of the film covering, anything greater than 10x8 will be difficult to get even airtight.

pentaxuser · Jun 8, 2020

Yes it looks as if the usual one day life that applies to B&W developer does not apply to colour without replenishment and testing for much more than 2 hours which is very short

pentaxuser

Wayne · Jun 13, 2020

My sessions are rarely more than two hours, and I've bottled and reused the chemicals over and over in new sessions (staying within the recommended capacity). Since new session usually means a new print, I'm starting from scratch with a test or three anyway. Since its so cheap, there's no reason to go crazy trying to squeeze every last square inch out of it, but I've seen no reason to toss it after one session either.

btaylor · Jun 13, 2020

I haven’t ever tried tray RA4. Am I the only one that cannot tolerate the odor of the developer? Drums certainly minimize it- plus you can work almost entirely in the light after its loaded. I even find it difficult to load the roller transport because the 100 degree developer makes quite a stink when I load the print. If it were me I think I would stick with drums, though I know many people here happily process in open trays.

koraks · Jun 14, 2020

btaylor said:
Am I the only one that cannot tolerate the odor of the developer?

Certainly not; I've heard of several people who didn't like it and who suspected it contributed to their headaches or affected their respiratory system. I never noticed this myself, but that doesn't say much of course.

Wayne · Jun 14, 2020

It doesn't smell any worse that possum urine, whadyaa mean? With good ventilation behind the sink pulling the fumes away, I don't notice it much. But for me, some chemical smell is part of the darkroom experience. It should not make you feel bad though, so if it does by all means use other methods.

pentaxuser · Jun 14, 2020

Wayne said:
It doesn't smell any worse that possum urine, whadyaa mean? .

Sound interesting but unfortunately possum urine in the U.K. is more difficult to find that Kodak bulk rolls cheaper than cassettes

pentaxuser

MattKing · Jun 14, 2020

btaylor said:
I even find it difficult to load the roller transport because the 100 degree developer makes quite a stink when I load the print.

A really good argument to use RA-4 at room temperature instead - as recommended by Photo Engineer.

Tom Kershaw · Jun 27, 2020

Partly due to the hot weather here in eastern England at the moment I did a full session today of RA-4 printing with open trays and found it worked very well. I gave about 2 minutes development time at approx 25°C room temperature. I'll probably continue in this vain as printing in trays is much less hassle than Jobo drums, at least for the relatively small 12"x10" paper I've been working with. I was using a small 15W ILFORD 908 dark green safelight that didn't seem to cause any issues.

pentaxuser · Jun 27, 2020

Just out of interest, Tom, what did a full session consist of in terms of time without presumably any sign of the chemicals deteriorating?

Thanks

pentaxuser

DREW WILEY · Jun 27, 2020

Annoying odor per se or not is not a valid indicator of potentially adverse health effects. Some of those slowly sneak up on you until there's suddenly a threshold of either respiratory illness or hypersensitivity. That's why I won't do RA4 in trays. And everytime someone goes around claiming it hasn't harmed them at all, I'm thinking, how many more rolls of the dice will it take till they regret that attitude? Well, I am personally sensitized. So I do all the actual chemical steps using a portable drum processor outdoors. And using chem one-shot, with just enough proportionately mixed per batch or daily session also gives me a higher degree of print repeatability. The mixing itself is done directly below a moveable duct which feeds into the main fume hood exhaust port, minimizing any exposure to fumes.

Tom Kershaw · Jun 28, 2020

pentaxuser said:
Just out of interest, Tom, what did a full session consist of in terms of time without presumably any sign of the chemicals deteriorating?

Thanks

pentaxuser

Around 6 hours, although I was performing other tasks in the darkroom at the same time so didn't put through a huge amount of paper. There may have been some fall-off towards the end but I had also switched film types and needed to sort out my filtration pack. At least I now seem to have worked out printing the Portra films onto Fuji CA.

pentaxuser · Jun 28, 2020

Thanks Tom. Well at least 6 hours is a lot better than 2 hours and in a concentrated session is probably long enough to make tray printing viable

pentaxuser

Donald Qualls · Jun 28, 2020

@Tom Kershaw That Ilford 908 filter you're using is intended for development by inspection with black and white film, is it not? I'm looking for the most practical way to avoid total darkness when I start printing in color, with room temp tray development, over the next few months -- I was leaning toward a 475 nm LED (yellow/slightly green), as that's precisely the sensitivity minimum for the the paper and thus the light can be brightest with a usable safe time. Are you running that 908 filter light continuous, or turning it on and off as you work?

Tom Kershaw · Jun 28, 2020

Donald Qualls said:
@Tom Kershaw That Ilford 908 filter you're using is intended for development by inspection with black and white film, is it not? I'm looking for the most practical way to avoid total darkness when I start printing in color, with room temp tray development, over the next few months -- I was leaning toward a 475 nm LED (yellow/slightly green), as that's precisely the sensitivity minimum for the the paper and thus the light can be brightest with a usable safe time. Are you running that 908 filter light continuous, or turning it on and off as you work?

I had the 908 filter (5"x7") safelight running continuously, the light outbox is extremely low with a 15W lamp, so it takes a while for vision to adapt to see around the darkroom. I could probably do with installing a second unit as I've found another dark green safelight filter - but I only have the one safelight housing. A specific LED safelight for RA-4 would be interesting.

Donald Qualls · Jun 29, 2020

There's an RA-4 filter available for the Thomas Duplex, too -- said to be quite bright and very safe due to the very narrow cut (basically singles out one of the two yellow emission lines of the sodium vapor lamp inside). Unfortunately, if you can find a Duplex it costs a mint, and you have to change filters for multigrade paper or ortho films -- and replacement bulbs also cost a limb or two. OTOH, 475 nm LEDs are cheap, and power supplies for them are inexpensive (not to mention no kilovolts required).

Tom Kershaw · Jun 29, 2020

Donald Qualls said:
OTOH, 475 nm LEDs are cheap, and power supplies for them are inexpensive (not to mention no kilovolts required).

Have you had a chance to arrive at an initial design yet?

pentaxuser · Jun 29, 2020

Donald Qualls said:
There's an RA-4 filter available for the Thomas Duplex, too -- said to be quite bright and very safe due to the very narrow cut (basically singles out one of the two yellow emission lines of the sodium vapor lamp inside). Unfortunately, if you can find a Duplex it costs a mint, and you have to change filters for multigrade paper or ortho films -- and replacement bulbs also cost a limb or two. OTOH, 475 nm LEDs are cheap, and power supplies for them are inexpensive (not to mention no kilovolts required).

The DUKA is the European equivalent of the Thomas Duplex but may be more difficult to get hold of in the U,S, than the Thomas Duplex and the bulbs for the DUKA are of course designed for European voltage but they do work at a level which I find to be much better than the dark green light despite the assertion that any safelight is unsafe and the only safe method is total darkness.

pentaxuser

Donald Qualls · Jun 29, 2020

Tom Kershaw said:
Have you had a chance to arrive at an initial design yet?

Well, as in "needs a small DC power supply, and one to three small low-power LEDs', yes. I'm not really an electronics guy, so I'm likely to find an existing LED light source and replace the actual LED modules with ones I can buy that have the correct wavelength and a narrow cut. I won't even know how much LED power I'll need until I can test one -- my pocket flashlight, pointed at the ceiling, would be plenty of light, but that would likely change if it were a single emission line. Certainly if I filtered to get to that narrow cut color, though the efficiency ought to be higher if it's a single-emission LED.

I might pick up one of the Harbor Freight LED flashlights next time they're free and replace the LED(s), and then run it on a rechargeable lithium cell; that should run for hours on a charge, and it's hard to get cheaper...

Open tray RA-4 developing: how serious is prolonged air exposure?

Dino Joe

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Open tray RA-4 developing: how serious is prolonged air exposure?

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