Chemical age -- metol

[Ulophot]

I'm trying to isolate the cause for anemic density in high values on negatives.

Recent testing with a controlled target in controlled continuous lighting astonished me by producing a low Zone VIII density with my normal development where a Zone X was expected. Low zones were correctly placed and showed expected development, indicating that my exposure was on target, thus that my meter was fine, unless some wild non-linearity has infected it, which was not apparent from the way I set up the target and lighting.

This came about during what has unfortunately become an extended saga of getting an LED head made and working out kinks. Therefore, I also checked the contrast rendering from the RGB LED panel with my new 4x5 21-step Stouffer transmission tablet. If my notes on its use, from a thread here last Spring, are correct, I should disregard the darkest not-yet-black step and the lightest not-yet-white step, count the number of steps between them (ignoring, of course, one of the two Step 11s, which are identical), and multiply by 15 to get a number corresponding to contrast grade standards. I adjusted the GB balance to get a scant 7 steps, thus something around 100 (Grade 2) for the unfiltered light. My paper was fresh.

Therefore, I am turning to my Metol (I mix D23), which I am near finishing up before ordering more, wondering if it could have weakened. That's the question I'm asking, prior to running out, prior to ordering more. I probably bought it 18 months ago; I should have dated the container. It's stored in a brown glass jar with a silicate packet. It's the same batch I have used for reliable, consistent, good density previously. I didn't think it was in danger of losing activity, but if that's the problem, fine. I am otherwise stumped on this problem -- just when I thought I finally had the variables under control. Grrrr!

Any knowledgeable/experienced thoughts? Yes, I will be ordering more but don't want to throw away what I have if some other factor may be at work.

[Michael R]

Seems more likely there is something else in the system/methodology which would explain why you’re not getting what you expect, but since you asked about metol, when fresh it should be white/off-white. As it oxidizes it will darken gradually toward brown and might also develop little dark specs. If it is slightly darkened from white it is still ok but if it is brown or has purple in it that’s no good.

[Tin Can]

Is it moisture?

metol chemical aging (https://scholar.google.com/scholar?q=metol+chemical+aging&hl=en&as_sdt=0&as_vis=1&oi=scholart)

[Joe O'Hara]

You take better care of your Metol than I do, Philip. I assume that you are using the same batch of sulfite as before. There aren't too many variables here! Which is good. Are you developing in trays, or using a drum? If you are doing it in trays and without closed-loop time or temperature control, remember that lower humidity in the darkroom will result in more evaporative cooling of the developer solution. (I use a cheap temperature controller from A-zon and a seedling mat under the tray when I develop that way, but I prefer the Jobo tank as it is much simpler.)

If I understand you, it sounds like your results are a little bit low in contrast with your filtration set at Grade 2. That should be readily printable on multigrade paper, but I suppose you wonder if something has changed. That's all I can think of at the moment, but I hope it helps.

[mdarnton]

I have metol from about 35 years ago that I still use and it's fine. It's even picked up a light brown cast through time, but doesn't seem to matter. D23 is generally a flat developer anyway, which is why I use it.

[Drew Wiley]

Just like in flintlock warfare, keep your powder dry. If the metol powder is dark brown, it's probably over the hill. The metol I'm using has been out of the same bottle for over 20 years. So mere age doesn't have a lot to do with it. Storage conditions might.

[Mick Fagan]

Just checked my plastic container of Metol, I bought it in April 1992, so 30½ years ago, still running perfect. Colour is definitely off white, but not brown, the odd dark speck was found.

Mixed a fresh batch of D76 last week, very nice negatives two days later.

[Ulophot]

Thanks to all. My metol easily passes the color test.

Part of my problem is that I am switching to the LED from a coldlight, which I was using sans 40Y, so it tended to be a bit contrasty to start with. However, I estimated that it was probably around Gr. 2.5, not 3 or higher. I standardized my N development on that with a Gr. Ilford filter when I came back to photography several years ago, with an N development time of 9 min in 1:1 D-23 at 68 with the standard, one-the-minute agitation I had used for decades. It appears that I'll have to increase my development times by some percentage, but I'm surprised by the amount implied by the test result, which indicates that my N is N-2 -- that's huge, and not very encouraging relative to my previous results, grain-wise, in 35 and 120.

However, I've been waiting for months to get this new system's variables locked in, with various moving targets, so to speak, and right now I'll do what it takes to finally do so. Though the thought of yet more testing is hardly thrilling. For decades I had my printing pretty well under control and perhaps it's not tooting my own horn overly much to say I became a pretty capable printer.

[Roberto Nania]

I have no direct experience with aged metol. Anyhow I was in for buying one kilo of old Metol few time ago; it was like more than 20 years old in a plastic container at half the standard price. I have a friend who runs one of the latest commercial darkrooms in northern Italy and he suggested me to refrain of buying it since storage conditions were unknown and he himself got issues of powder chemicals that crystallized in few years and changed their chemical properties.
We all know also what happened to D76 and Xtol powder being unusable for a wrong quality of Kodak packets that lead oxygen to react with the chemicals in normal storing conditions.
What is the price of Metol in US? In Italy it is at around 30€ for 0.100 kilo.

[Doremus Scudder]

Philip,

I'd be looking elsewhere for your problem and not at the Metol (I, too, have 30+-year-old bottles of Metol, hydroquinone and phenidone that all work just fine).

Although it's hard to believe that your same "normal" time from earlier would give you an effective N-2 just by changing light sources, that's still worth checking out, especially if your negatives are contrasty and show similar densities to earlier negatives. Maybe a comparison from negs you know printed well with the older light source would be in order. Also look for any mistakes you might have made with your filtration/color mix when printing. Something may be up with the new light source that you haven't taken into consideration.

However, if the cause is underdevelopment, i.e., if your negative look less contrasty than earlier ones, then look at developer dilution (mistake maybe?), temp/time combination, or developer exhaustion (not enough developer volume for the amount of film).

I'd likely be re-running my test and developing several negatives for different times, starting at your old "normal" time and then adding 20% or so to each successive negative from the previous one.

Keep us posted,

Doremus

[Ulophot]

Hi, Doremus. I'm still a bit stumped, after another couple of tests, but still working on it. I just mixed a fresh batch of developer, in case I did make a mistake in the last batch. Not sure how I could have miscounted 4 teaspoons of Metol but I've done more foolish things before.

I think I will pull an old neg for which I have printing data recorded and see how that fares; I probably have a proof print of as well as contact sheet. I just processed another neg in the fresh developer, using my same test set-up illuminated and exposed to give me Zones 0-VIII with most included. Development time was 11 min 1:1 @ 68, 25% more than my previous 9-minute N, and I also increased the agitation to every 30 seconds. That's already more than should be necessary; I'm quietly fending off feelings of utter incompetence. My meter seems to be on target , as tested in sunlight this morning, and I haven't been throwing my thermometer at cement walls or baking it in a hot oven... The latest neg may have gotten me a good Zone VIII. I'll know as soon as it dries. I'm using my spot meter as a densitometer.

The new LED color is certainly less blue. I had to replace the first LED panel after getting some wires in the "prototype" caught in the enlarger superstructure. The new one requires closer balance of green and blue, although I tested the last one with a borrowed Stouffer and this one with my own, new one, just arrived. But I doubt the old one was faded, for various reasons. I feel as if I have been swimming in a sea of changing variables since I returned to photography.

Stay tuned.

[Tin Can]

Your OLD head had a channel out?

and you compensated...

good luck




I mean that

[xkaes]

I have metol from about 35 years ago that I still use and it's fine. It's even picked up a light brown cast through time, but doesn't seem to matter. D23 is generally a flat developer anyway, which is why I use it.

Same here. I got a 5 pound jar way back when. Still as good as new.

[Michael R]

I’m betting on something with the DIY blue/green LED head as they are not necessarily that simple to design/make. That would seem to be the most likely place to look, but that’s just a guess really as I had a hard time following the end-to-end procedure/test methodology which led to the unexpected contrast results. I really doubt it’s the D-23, which can stand a fair bit of slop (amounts, metol quality, sulfite quality) before failing materially. If Philip has access to a pH meter, just to “cross the Ts and dot the Is”, D-23 should be around pH 8.

[Ulophot]

Well, I have found part of the issue, but not all. By projecting the Stouffer scale, rather than contact printing it, my green-blue balance has changed significantly, even though I have been using diffusion enlarging for many years and my Componon glass is immaculate. I dialed back the green to near where it was with the previous panel, to get 7 steps of gray (not including the two closest to black and white, respectively) in a ~5x7. print. The balance is now 150G, 255B, with R150. I suspect the imbalance of G-B is due to the green tendency of LEDs generally and the less-than-ideal blue from the cheap 16x16 LED panel -- I have noted that those using single green and blue LEDs specify Royal Blue as opposed to other blue LEDs as necessary to achieve a true Gr. 5.

Exactly how much of the problem my previous setting represented, I have not measured precisely. Another bizarre anomaly popped up last night, in which the 12 minute neg had less density than the one developed just before it for 11 -- same dev batch, same temp, same agitation. The only variable I can think of was slight temp loss during the course of development, but that would not account for the difference. Sometimes I wonder if I've gone senile. Anyway, I have another 12-min neg, carefully temp-controlled, drying now, so I'll soon see what that yields. I'm agitating every 30 sec now, something I have never done since I started developing film in 1968; always on the minute when not using my rotating tank (small batch 4x5 is now in my Stearman tank). I'll be so glad when this episode is over!

[Ulophot]

I breathe a public sigh of relief, that the latest neg is right on target, though I'm still surprised that I needed 33% more development plus additional agitation to get it. Now I'll have to adjust and confirm the rest of my times, at least a "spot check" to indicate that the new times are in line with this. With luck, I'll get that done today and be done with all this testing, for now at least.

As always, thanks to the valuable contributions of others in this thread. Just to know that someone else is ready to assist, helps to get through such confusing moments.

[Ulophot]

Just a note to say that I'll sleep better tonight: N+1 and N-1 followed suit with the N adjustment, so, besides a tweak to be made here or there, I'm feel myself back on solid ground. Phew! I told that to my wife tonight, and she replied, "It's an illusion." (Forty-five years of marriage, for that?)

Now I can get back to figuring out times with DD23, which is how this all got started to begin with, when my N development looked like N-2. Perhaps this will go a bit more easily. I won't repeat my reasons for trying it, given in my OP. I'll post when I have some useful results.

[koraks]

Ulophot in not sure when you talk about balancing blue and green, you expect to be able to somehow copy ratios from e.g. old-style cold light sources over to LED or that a 1:1 ratio in your particular LED setup means the same as a 1:1 ratio in any other kind of light source. If so, forget about it, because it doesnt work that way. Unless you are measuring intensities on an absolute scale like uW/cm2, color ratios are completely idiosyncratic to the light source used. For instance, you use LED and so do I, but I can guarantee you that my 1:1 blue:green ratio prints totally different from yours and that's not only due to differences in peak wavelength of the LEDs used.
So I'm not sure if you're trying to use your blue/green ratio in your LED head as some kind of benchmark for your film development, but if so, keep in mind you're chasing ghosts (and irrelevant ones at that!)

[Ulophot]

Hi, koraks. Thanks for your comments. Allow me clarify my thinking and procedures here.

If one uses a 211 or 212 bulb in a condenser enlarger, as I did for years, the unfiltered light gives the same, or virtually the same, contrast print as yielded by the same source with a #2 filter. At least, that was my experience, with both Kodak and Ilford filters years ago. When I got a coldlight, I took the advice to put 40Y in the path to get back to Grade 2 from the bluer, more contrasty light. However, after 13 years away from enlarging, I returned about 5 years ago, and, after some experimentation and consideration, decided to use the cold head without the 40Y, just the Ilford filters. My tests at the time indicated it was about Gr. 2 1/2 unfiltered, and I tended toward gentle negs anyway.

As indicated above, the LED head, which uses a cheap 16x16 RGB panel, was an open question when I began using it. I eventually borrowed a friend's Stouffer 21-step scale and used it for contact prints so that I could dial in an unfiiltered Gr 2. It end up at around 150G, 240 B. Through various "adventures" between then and recently, including replacing the LED panel -- long story short -- I got my own Stouffer and made projection prints this time, retesting to get the same contrast whether I used no filter or a Gr. 2 Ilford one (this time, 160G, 255B), and found that with a Gr. 2 coming from the head, my Normal film development was yielding a neg with grossly inadequate density. My exposure was just slightly less than it should have been for the test (bellows comp), but the 9 min development was landing Zone X on Zone VIII. A new set of tests has brought my N development to 11 1/2 or 12 minutes, with appropriate additions to my N-1 and N+1, which is as far as I have gotten.

Thus, all I have been doing with the balance adjustment is striving for a resulting Gr. 2 proximate to a densitometric standard. That gives me an anchor for my film development as well as for making contrast adjustments in printing.

[koraks]

As indicated above, the LED head, which uses a cheap 16x16 RGB panel, was an open question when I began using it. I eventually borrowed a friend's Stouffer 21-step scale and used it for contact prints so that I could dial in an unfiiltered Gr 2. It end up at around 150G, 240 B. Through various "adventures" between then and recently, including replacing the LED panel -- long story short -- I got my own Stouffer and made projection prints this time, retesting to get the same contrast whether I used no filter or a Gr. 2 Ilford one (this time, 160G, 255B), and found that with a Gr. 2 coming from the head, my Normal film development was yielding a neg with grossly inadequate density. My exposure was just slightly less than it should have been for the test (bellows comp), but the 9 min development was landing Zone X on Zone VIII. A new set of tests has brought my N development to 11 1/2 or 12 minutes, with appropriate additions to my N-1 and N+1, which is as far as I have gotten.


Alright, thanks for explaining, although I'm not sure I can follow. I don't mind if you want to keep it at this without answering my questions, which are more out of curiosity - although also some concern if your LED source is doing what you think it may be doing.


>retesting to get the same contrast whether I used no filter or a Gr. 2 Ilford one (this time, 160G, 255B)
Does this mean you need a different blue/green ratio since replacing the led panel?
Is it correct you're using a grade 2 filter in combination with your led panel? If so, why?

> with a Gr. 2 coming from the head, my Normal film development was yielding a neg with grossly inadequate density
Inadequate density, or insufficient gamma?

If your light is 'grade 2', then it will be so regardless of the negative used. If your negatives that printed with the desired tonal scale on grade 2 don't print the same with a new light source, it means the new light source isn't "putting out grade 2" so to speak.
If you mean that your negatives have insufficient overall density, i.e. your Zone X ends up VIII but your zones I through III all drop into dmax, then you don't have a problem with your negative, but you're just overexposing the print. Dial back light output, stop down etc.

I have a feeling you're trying to fix a misunderstanding about how a LED light source works by changing negative development, which would be tricky proposition to say the least. But perhaps it's just my misunderstanding your explanation that needs fixing ;)

[Ulophot]

I'm happy to answer your questions. I used to think I was an able writer and communicator.

I use a Gr 2 filter with the new LED head, typically, because going from no filter to, say, 2 1/2 or 3 changes the exposure more than from 2 to another such filter (save the extremes).

I used the Stouffer tablet to calibrate the contrast of the LED light (G-B balance) to output Gr. 2. I will not be changing that balance to change contrast; rather, I use the Ilford filters in the usual manner. As a result of the calibration, a print made with no filter is identical in contrast to one made with the 2 filter in place, once the time is compensated.

I should have said gamma, rather than density.

I do not have a problem with over-exposing my test prints. I test a clear area of the film for virtual D-max first. I say virtual, because I learned long ago that I had been overprinting in quest for deep black. As Bruce Barnbaum and others point out, the eye is not necessarily a good densitometer when comparing total black to near total. Since I selenium tone my prints, my "virtual" D-max is deepened adequately. When testing for exposure, I use good light to examine dry test strips if I'm making important prints.

For proofing negs, I fall into the camp that prefers a somewhat lower contrast proof in order to see details at both ends a bit better. I standardize proofing with Gr. 1 1/2 and occasionally confirm my times with processed blank film of the relevant format.

I hope this responds clearly to your questions. Let me know if I have failed again.

[Alan Townsend]

I'm still using out of a one pound jar of Kodak Elon, also known as metol, that I purchased in 1972. That makes it 51 years old. I wasn't especially careful with storage conditions for many years time. It is now a light tank color instead of white, but works just fine.

I know this thread is old but had to chime in since I have an Elon older than Musk, or so I thought. Actually, he was born in 1971, so is a year older.

[xkaes]

I'm still using Kodak Elon from a five pound plastic jug. I had no idea that Kodak packaged it for sale in such large quantities, but it was too good a price -- I don't recall, but I assume so close to free I couldn't pass it up. I have no idea how old it is because I bought it "used" a LONG time ago -- when it was half empty. There is no date or year on the Kodak label, but the selling price was $85. I've never weighed it, and it's still close to half-full, and still works fine. It's still pretty white, only very slightly eggshell white, but I live in a dry climate.

So my conclusion is that Kodak's Elon is infinitely more stable than Musk's Elon -- but, of course, that's not saying much.

[David Lindquist]

I wonder for how many of us the Kodak product is the first thing we think of when we see Musk's first name.

David

[LabRat]

Elon was around a lot longer than when Musk started to wiggle...
And so was Musk... ;)

But with these older plastic Kodak jars, I have had a few start to crack/disintegrate and eggshell-like chips of the jars were nearby or inside, so it's wise to transfer the chems to sealed glass jars (like canning jars) before failure...

Also the steel lids can rust severely contaminating chems, so catch that early also...

Steve K

[j.e.simmons]

Gerald Koch told me that the glass Mason jars were good for chemicals, but to keep them in a dark cabinet as they are clear glass. He agreed with Steve that the caps should be watched.