View Full Version : Water Timer for print washers
I use two archival print waters, one 20x24 and 11x14. The were hooked up to a garden hose outlet with a y splitter, and since I go by the "fill and dump" method of print washing, I would just turn on the water, adjust the diverter to open the valve for whatever print washer I was using at the time, and let the print washer fill up before turning off the faucet. After a couple of hours of print soaking, I'd open the hose again, and fill it up with fresh water again. Fill and dump 4 times at 1-2 hour intervals, for 6-8 hour wash in total. Very tedious.
So how about using a garden hose timer to do this overnight --- but I surprisingly found out that the most popular timer model can only work in min 6 hour intervals. I need one that can do 2 hour intervals or shorter, and ideally has at least two separete output valves which are either independently programmable, or at least run on the same interval. Any suggestions or experiences, or better ideas welcome!
Steven Tribe
7-Apr-2014, 15:41
Use 3 in parallel - offset by 2 hours. You would only have to have 2 X connections and only a small section with triple hoses.
Very tedious.
I'll say. Just curious, why aren't you using the "archival" washers as intended? Saving water? The whole purpose of the Gravity Works style washers is to function as automated fill and dump.
Yup saving water and also i think soak and dump over long time is a better way to wash prints since you dont have to rely on the design of the washer to have even flow over the prints.
I have the gravity work film washer. Not for prints.
Use 3 in parallel - offset by 2 hours. You would only have to have 2 X connections and only a small section with triple hoses.
Well I was hoping not to get into complicated hose connections. So the three outlets from the three timers are hooked up together and go to a washer? That's a heck of a workaround the 6 hour interval!
Curious, if you acquire a water time with an interval as you need , how do you propose to dump the water on a interval basis to match the filing of the washer?
Look into timers for drip irrigation. They might have more flexibility.
I fill it from a bottom hose. It "drains" by overflowing around the top of the entire print washer, onto a sink below. the print washers have drains but I don't use them -- I just let them overflow instead.
I suppose it is possile to place another timer on the drain side so it drains the print washer and then shuts off just before fill time - that way the fresh water enters an already-emptied washer, but there's no real reason for this since the point is simply that there be enough volume of fresh water present to continue the diffusion process of chemicals out of the print, but there is indeed some mixing.
Also, I don't like to see prints stuck emulsion side against the print washer interior surface, and that tends to happen when you first drain then refill the tank rather than let it overflow. I dont know if the print being stuck to the side of the washer really hurts the washing process but I just don't like it.
The length of time the prints spend soaking is the key and thankfully I have not had issues with emulsion coatings sloughing off. Four soaks overnight seems to be enough, but this is following an initial rinse and hypoclear rinse.
I then give them a final rinse in RO water to reduce tap water contaminants and water spots.
Look into timers for drip irrigation. They might have more flexibility.
I will. Thus far I've discovered that pot grower stores often have the sort of very convenient plumbing and other supplies that darkrooms need! I'm hoping people in the MJ growing business have a need for flexible water timers ...
Bruce Barlow
8-Apr-2014, 05:04
Have you tested, and KNOW that you need to wash prints that long? It feels long to me, and that you might be creating a problem where none exists.
Just asking. I can't say I know anyone who washes that long, except me when I forget. My similar "stand-and-dump" procedure has me change water three times in an hour and a half, and an HT-2 test comes out just fine. Zone VI 11x14 washer, 8x10 fiber prints, 8 gallons of water to fill it up. I have a 1-gallon-a-minute regulator on the hose, and leave it run for washing film, just in case.
Just a thought.
part of why they're called "archival" print washers is because they're designed to drain from the bottom. not that you care but your wash times could be much shorter/thorough if done properly.
part of why they're called "archival" print washers is because they're designed to drain from the bottom. not that you care but your wash times could be much shorter/thorough if done properly.
What difference would it make which end they fill or drain from to the archival qualities of the print?
I don't mind long wash times, I have the time to do it right.
there are other threads on this that go into detail on the reasons why. your prints should also (if they're not already) sit up off the bottom of the washer.
residual hypo is heavier than water so it sinks to the bottom.
Have you tested, and KNOW that you need to wash prints that long? It feels long to me, and that you might be creating a problem where none exists.
Just asking. I can't say I know anyone who washes that long, except me when I forget. My similar "stand-and-dump" procedure has me change water three times in an hour and a half, and an HT-2 test comes out just fine. Zone VI 11x14 washer, 8x10 fiber prints, 8 gallons of water to fill it up. I have a 1-gallon-a-minute regulator on the hose, and leave it run for washing film, just in case.
Just a thought.
I used to do the Ht2 test but that's for residual fixer only and even then is only an eyeball approximation not the ansi approved method of testing. Indeed a much quicker wash esp with hypoclear would result in a print that would pass the HT2 test but I wouldn't be comfortable just with that. That's the minimum washing.
Because of the many variations involved (temp, water quality etc) the only real conclusion and rule of thumb about print washing, is longer is generally better
Look at it this way: the print is meant to last 500 years, if washed right. In comparison to 500 years, a couple extra hours of washing doesnt hurt the print, I'm in no rush, and I can do other things while the print is soaking. I've often left prints soaking over the weekend by accident, with no negative consequences. no bleaching of brighteners etc.
The only concern I had was removing TOO MUCH thio since a trace amount is considered to be good for archival purposes, but I don't flatter myself into thinking my procedure is anywhere near 100% effective in totally removing all thio
residual hypo is heavier than water so it sinks to the bottom.
No Vinny, this is a myth. Please lets kill it here and now once and for all.
Yup saving water and also i think soak and dump over long time is a better way to wash prints since you dont have to rely on the design of the washer to have even flow over the prints.
I have the gravity work film washer. Not for prints.
OK, if saving water is your paramount concern, god bless you. But just to clarify, film washers generally work differently than print washers (except that I also happen use my cross jet-style print washer to wash sheet film). They are almost exclusively either flow through or automatic fill-and-dump (AFAIK).
You've indicated you have "archival" print washers. Presumably you either don't have the The Gravity – EcoWash constant over-under flow design, or they also use too much water for you.
There's certainly nothing wrong with straightforward fill and dump measures, if you can keep on top of it, but as already mentioned, some papers cannot sustain long washing times. You might want to search the thread where this was discussed in the last few weeks. This all comes down to an inescapable conclusion. Washing papers for the manufacturer recommended times likely puts water use by a low constant flow unit at parity with, say, basic fill and dump for the required interchanges over the same period of time.
Are you sure you're not trying to re-invent the wheel? :confused:
OK, if saving water is your paramount concern, god bless you. But just to clarify, film washers generally work differently than print washers (except that I also happen use my cross jet-style print washer to wash sheet film). They are almost exclusively either flow through or automatic fill-and-dump (AFAIK).
You've indicated you have "archival" print washers. Presumably you either don't have the The Gravity – EcoWash constant over-under flow design, or they also use too much water for you.
There's certainly nothing wrong with straightforward fill and dump measures, if you can keep on top of it, but as already mentioned, some papers cannot sustain long washing times. You might want to search the thread where this was discussed in the last few weeks. This all comes down to an inescapable conclusion. Washing papers for the manufacturer recommended times likely puts water use by a low constant flow unit on parity with, say, fill and dump for the required interchanges over the same period of time.
Are you sure you're not trying to re-invent the wheel? :confused:
Yes I have the 4x5 gravity thing that fills and dumps to wash 4x5, I consider it to be neat toy for washing film (but I don't really use it since I don't develop more than 2or 3 4x5 negs at a time, and quick tray washing is more than sufficient for negs with hypoclear, no need for repeated fill and dump cycles over long period of time.)
As you say, prints are an entirely different matter because they don't wash anywhere nearly as quickly as film does since the paper fibre absorbs the chems. The gravity type print washers use way yoo much water
I have not had an issues with the paper I'm using for fill and dump even over extended periods. Standard ilford double weight glossy survives the soak cycles just fine, for me at least
The point of getting a timer is to "stay on top of it" as you say, but automatically. Which is why I was asking if anyone knows of a timer that uses shorter intervals, the original purpose of this thread.
Folks, print washers, even the "archival" ones that are made out of plexi and have the separate slots for prints, are not exactly hi tech. They're all just tanks that are meant to hold larger volumes of water. Doesn't matter which way you fill it, doesn't really matter if you fill it gradually with a trickle or fill and dump, doesn't matter if they make the water do backflips. They all function by the same principle of diffusion, which is generally a logrithmic function. The point is to keep the print in a larger volume of clean water and then give the thio time to diffuse out. There's no magic involved. Time, temp, and concentration differentials is what drives diffusion. The temp is room temp, a constant. So we can make the washing process more effective by increasing the time, and/or the volume of fresh water. If you don't want to waste water, then you have to simply increase the time. And since that doesn't hurt my paper in m particular case, that's all there is to it really: Soak longer to take advantage of the "long tail" of the function, before dumping and refilling
Kirk Gittings
8-Apr-2014, 10:39
residual hypo is heavier than water so it sinks to the bottom.
No Vinny, this is a myth. Please lets kill it here and now once and for all.
I fell for that for like 30 years-makes me feel better about my homemade film washer which just uses overflow for exchange.
Bruce Barlow
8-Apr-2014, 11:54
No Vinny, this is a myth. Please lets kill it here and now once and for all.
Hate to tell you (well, no I don't), but sodium thiosulfate is denser than water, and denser liquids sink. Less dense stuff floats.
Vinny wins on a TKO.
Google enlightens once again.
chuck461
8-Apr-2014, 12:31
http://theonlinephotographer.typepad.com/the_online_photographer/2011/07/fixer-doesnt-sink.html
Harold_4074
8-Apr-2014, 13:11
cyrus,
I have contemplated exactly the same thing for different reasons: my well water has a lot of dissolved gases, so at the "proper" flow rate for my Calumet washer the prints get covered with bubbles and I have to either shift them manually or periodically blast the water flow to clear the surfaces.
If you are even minimally proficient with electrical stuff, you can use pair of modular timing relays and a lawn sprinkler valve (bonus: built-in vacuum breaker!). The relays that I am most familiar with (Microtime DSQUD3) are something like $50 from McMaster-Carr, although I don't doubt that you can get the same or an equivalent for less. They allow timings (via switch setting) from 0.1 second to 63 minutes and can easily be set up to repeat-cycle with independent on/off durations.
Most of the alternatives that I know about (including the "misting" timers for plant propagation) are either more expensive, require line-voltage wiring, or both. So far, I haven't come across a (cheap) non-pilot-operated, 24VAC valve for dumping the water, but there must be one out there somewhere!
Kirk Gittings
8-Apr-2014, 16:33
We just had a discussion on this site about this recently, but I can't find it. The conclusion was that the fixer (even though heavier) remained in suspension and hence did not sink to the bottom of the washer.
We just had a discussion on this site about this recently, but I can't find it.
it sunk to the bottom!
hahaha. sorry, couldn't help it.
If you are even minimally proficient with electrical stuff, you can use pair of modular timing relays and a lawn sprinkler valve (bonus: built-in vacuum breaker!).
Thank you -- that is a great idea. Alas, while I understand the theory and can write equations all day long, I am not at all actually proficient in anything practical, and live in fear of getting electrocuted by my coffee cup warmer.
However it is interestlng how many other skills one has to acquire just to take some damn photos! Just to build the darkroom, Ive dabbled in plumbing, fiberglassing, tiling, flooring, masonry, painting, carpentry, light welding and now this. My tool collection is growing much faster than my print collection at this point. I am not a handy guy but thus far all my fingers are intact
Vinny wins on a TKO.
TKO-ing me is about as simple as blowing on dandelions, and I would hate to be in a ring with a Vinny.
The 'fixer falls to the bottom' idea has been around for a long time and lots of peoplle buy it because it sorta makes sense, is not totally wrong and reminds people of haloclines they have seen on tv nature shows
Ctein has a longish explanation for why this is a myth but this is the version I use:
Take a cup of salty water. Take another cup of fresh water. Combine them. What do you get? Two cups-worth slightly less salty water. The salty water and fresh water do not separate nor does the salty water go to the bottom of the combined cup. All you did was dilute the salty water by adding more water. Fixer is similarly just a salt, like table salt, (though not edible.) Of course if you're very careful and pour very slowly, and use very cold salt water, you can create a mini halocline in a cup - a neat science experiment for kids if you use food colorng in the water - but that's just temporary and shortlived as the salt moves from higher concentration to lower concentration and it all mixes up by itself. See http://www.youtube.com/watch?v=gx3yNjd7jE0
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