Ethol LPD Print Capacity

[logan2z]

Another Ethol LPD question

This developer is said to have a large print capacity. At the moment I'm not replenishing the developer and I'm getting only about 12 double weight 11"x14" fiber prints out of it before developer activity is noticeably reduced. That doesn't sound like that much. I'm diluting the developer 1:4 from the liquid concentrate.

According to the data sheet for Ilford Multigrade Developer, its print capacity is 50 8"x10" prints on Ilford fiber paper, so I assume around 25 11"x14" prints. And that's at a 1:9 dilution of the developer. So double the print capacity with less developer concentrate.

I switched from Ilford's developer to LPD because the former doesn't last long in the tray or in bottles between print sessions. LPD seems to last much longer in the tray and can be used across several sessions. But I am a bit disappointed in the print capacity of the developer given its reputation for 'huge capacity'.

What are other LPD users seeing in terms of print capacity for fiber prints in a non-replenished system? I know that replenishing can greatly extend the life of the developer, I just haven't gotten around to figuring out a good replenishing scheme when using the liquid developer.

 

[NedL]

I don't know the answer, but am curious how much working solution (1:4) are you using?

 

[logan2z]

I don't know the answer, but am curious how much working solution (1:4) are you using?

I'm using 2L.

 

[koraks]

I'm using 2L.

6 11x14 prints per liter effective capacity sounds abnormal by any stretch of the imagination. I'm not an LPD user, but no print developer should perform this badly, so something's not right. How have you determined this capacity, and what time and temperature do you use?

 

[logan2z]

How have you determined this capacity, and what time and temperature do you use?

I've determined the capacity empirically by observing when the print densities start to be noticeably off. I'm developing prints for 2 1/2 minutes at about 70 degrees F.

FWIW, someone at Freestyle Photo told me that they estimate the capacity of LPD at about 20 11x14s, but they didn't specify whether this was fiber or RC. Either way, not a big number.

 

[koraks]

Well, I'll leave this to the LPD experts, but a developer that will only do a handful of prints per liter 2.5 minutes would be of no use for me, personally. I'd be surprised if that's an inherent property of LPD - surely, it can't be such a compromised product!

 

[logan2z]

Well, I'll leave this to the LPD experts, but a developer that will only do a handful of prints per liter 2.5 minutes would be of no use for me, personally. I'd be surprised if that's an inherent property of LPD - surely, it can't be such a compromised product!

I can't explain it, certainly not what I expected. I have to assume it's something I'm doing that's severely limiting the developer's capacity, but I'm not sure what that could be.

 

[koraks]

No, me neither; it's puzzling! And certainly frustrating, too. I'm sorry I can't help.

 

[RalphLambrecht]

I've determined the capacity empirically by observing when the print densities start to be noticeably off. I'm developing prints for 2 1/2 minutes at about 70 degrees F.

FWIW, someone at Freestyle Photo told me that they estimate the capacity of LPD at about 20 11x14s, but they didn't specify whether this was fiber or RC. Either way, not a big number.

doesn't this all depend highly on the type of image and how much full black needs to be developed?

 

[Milpool]

Add me to the list of puzzled people.

I’m not an expert on LPD and when I did some quick searching for dilution instructions for the liquid version I ended up confused by conflicting information from Ethol and Freestyle… I assume the proper instructions are on the bottle and 1:4 is indeed the “normal” strength dilution?

All I can come up with is perhaps the liquid concentrate is old and weakened? What colour is it? Something going wrong during dilution/mixing? (although I don’t know what that could be as long as you aren’t being really sloppy which I assume you are not, so that’s a long shot).

I can't explain it, certainly not what I expected. I have to assume it's something I'm doing that's severely limiting the developer's capacity, but I'm not sure what that could be.

 

[logan2z]

Add me to the list of puzzled people.

I’m not an expert on LPD and when I did some quick searching for dilution instructions for the liquid version I ended up confused by conflicting information from Ethol and Freestyle… I assume the proper instructions are on the bottle and 1:4 is indeed the “normal” strength dilution?

All I can come up with is perhaps the liquid concentrate is old and weakened? What colour is it? Something going wrong during dilution/mixing? (although I don’t know what that could be as long as you aren’t being really sloppy which I assume you are not, so that’s a long shot).

The dilution instructions are on the bottle. 1:4 is for a neutral tone.

My bottle of concentrate is pretty clear with a bit of a pink tinge to it. It's the 1 gallon bottle. I had a 1 qt bottle previously and it looked the same.

I'm pretty careful when measuring/mixing the working strength from the concentrate - I don't think even I could screw up making 2L of 1:4 working strength. It doesn't get much easier

 

[NedL]

I'm using 2L.

Then I agree, it seems surprisingly low to me.

 

[logan2z]

doesn't this all depend highly on the type of image and how much full black needs to be developed?

I believe so. But the images I'm printing at the moment don't have a lot of full black in them.

 

[koraks]

doesn't this all depend highly on the type of image and how much full black needs to be developed?

In principle, yes. Halides (mostly bromide, and/or chloride) will dissolve in the developer as exposed silver halides are being developed. This acts as a restrainer, slowing down the developer and shifting image tone to warmer - the same as adding potassium bromide, since that's what essentially happens. Also, the pH will drift down very slightly and the actual developer is depleted through its action, although I doubt either of these processes is very significant.
Moreover, the developer oxidizes to the air, which of course is relevant when developing in trays and over a longer period of time. I've never experienced this to be a problem during a normal darkroom session of a couple of hours. I do expect this effect to swamp the oxidation of developer through its primary action. IDK.

So there are effects that are image-wise, especially halide leaching. But you'd have to run a print developer quite close to its limits to experience effects of this to the degree @logan2z reports them.

 

[logan2z]

Moreover, the developer oxidizes to the air, which of course is relevant when developing in trays and over a longer period of time. I've never experienced this to be a problem during a normal darkroom session of a couple of hours. I do expect this effect to swamp the oxidation of developer through its primary action. IDK.

I should mention that I am printing using open trays and using the developer over multiple sessions, storing it in tightly capped amber glass bottles between sessions. But LPD is supposed to have a long tray/storage life so I didn't think this would be the reason it would go off so quickly.

 

[Milpool]

That could potentially be an issue. Working solutions generally do not store well.

Granted we don’t know the full composition of LPD, but we do know fundamentally it is a PQ developer, not some totally exotic thing.

For what it’s worth I’ve always assumed the L in LPD to have more to do with the replenishment regime recommended by Ethol than anything else. Who knows.

One potential alternative (if you aren’t able to improve this particular situation) might be Liquidol. Ron Mowrey formulated it to be a longer lasting Dektol. I’ve never used it so I can’t comment with personal experience.

I should mention that I am printing using open trays and using the developer over multiple sessions, storing it in tightly capped amber glass bottles between sessions. But LPD is supposed to have a long tray/storage life so I didn't think this would be the reason it would go off so quickly.

 

[GregY]

I believe so. But the images I'm printing at the moment don't have a lot of full black in them.

I've used LPD a lot and always at 1:2 or 1:3....... same as 130....

 

[koraks]

I should mention that I am printing using open trays and using the developer over multiple sessions, storing it in tightly capped amber glass bottles between sessions.

On the occasions I've tried to keep an unreplenished working solution over the course of multiple sessions, I ran into trouble comparable to yours. Activity drops gradually or sometimes even precipitously. These days I use my developer (ID62 currently), then top off/replenish with fresh concentrate and a little water so the bottle is entirely full and store away. I've been doing this for a few years now (ID78 initially, now ID62) and it works well. Replenishment introduces fresh sulfite to protect the developer from oxidizing. If you don't replenish, the sulfite oxidizes into sulfate (causing pH drift), ultimately leaving the developing agents unprotected and they'll start to die. Maybe that's what you're running into.

 

[logan2z]

Ok, so I may have been seduced by the 'Long Lasting' marketing of Ethol In my defense, there's a ton of threads online that say it lasts forever, has long tray life etc. etc. Maybe those are all implicitly referring to using it in a replenishment regimen.

As a little experiment, when it started to go off during a printing session a couple of nights ago I decided to mix up 300ml of a 1:2 dilution of the liquid developer and add it to the tray. The activity seemed to immediately come back to the levels of fresh developer and the print looked virtually identical to one I made with fresh developer. The earlier quote I posted from an old Ethol PDF did mention mixing replenisher 1:2 from the concentrate and topping up the tray after 20 prints. I never print that much in a single session.so will probably rarely need to do that. But I think I will start to top up my developer with the 1:2 replenisher at the end of printing sessions. Will that provide enough protection for the developer to keep it from going off between sessions?

 

[koraks]

I'd give it a try and see how it goes, yeah.

 

[logan2z]

I'd give it a try and see how it goes, yeah.

Thanks. Is it better to mix a gallon of replenisher from the start as suggested by Ethol and use it as needed, or to mix it in smaller quantities from concentrate as I go? I assume the developer would have longer shelf life in the more concentrated form but I could be wrong.

 

[MattKing]

The suggestions from Ethol seem to mostly or entirely be based on the powder version, where mixing the entire amount is necessary for consistency.

 

[logan2z]

The suggestions from Ethol seem to mostly or entirely be based on the powder version, where mixing the entire amount is necessary for consistency.

Thanks Matt, that makes sense.

 

[albada]

Here are Ethol's claims about LPD, taken from https://www.digitaltruth.com/products/ethol_tech/ethol.pdf :

@Milpool is correct: It appears that the "L" in LPD assumes you are replenishing. That's misleading because all developers last longer when replenished.
In the second paragraph, they claim that the stock solution (concentrate) lasts a long time. But that's also true of other developers.
I'm not impressed.

I've found that the tray lives of Liquidol and ID62 are about the same: two or three sessions. I prefer ID62 because I found that Liquidol gives blacks a slight greenish hue visible in bright light, whereas ID62 yields neutral blacks. Long ago, somebody posted a formula that's supposedly similar to LPD. It's close enough to ID62 (also PQ-based) that I doubt anyone could see the difference.

I like ID62. The OP is in the USA, so he can buy the ingredients from photoformulary.com and artcraftchemicals.com .

Mark

 

[gijsbert]

I use the liquid LPD 1:2 and add some 1:1 when I start a session usually 50ml (so 25ml from the liquid lpd + 25ml distilled water).
I rarely do more than 8 8x10 per session so I think 50ml is even more than required, but it's so cheap compared to paper that I don't bother to optimize.
I'm a little jealous you can do 12 11x14!
The LPD diagram from the other thread suggest replenishing after 30 prints in half a gallon, which you get pretty close with 12 11x14, and that's with 1:2 strength (probably, the manual is not awesome). So I'd try to replenish a bit half way your session.

I've reused the 'same' developer with replenishment for several years, the dev gets pretty dark but keeps working. Only once did it die on me, in that I couldn't get a good black any more. I am not sure what happened, maybe I contaminated it somehow or the heat in summer made it go bad.

I think LPD can only be cheaper if you reuse+replenish otherwise it's hard to compete 1:4 with say Ilford multigrade 1:9 - or even 1:14!