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Thread: Chemical age -- metol

  1. #1

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    Chemical age -- metol

    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.
    Philip Ulanowsky

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  2. #2

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    Re: Chemical age -- metol

    Seems more likely there is something else in the system/methodology which would explain why youíre 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 thatís no good.

  3. #3
    Tin Can's Avatar
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    Re: Chemical age -- metol

    Is it moisture?

    metol chemical aging
    Tin Can

  4. #4
    Joe O'Hara's Avatar
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    Re: Chemical age -- metol

    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.
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  5. #5

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    Re: Chemical age -- metol

    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.
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  6. #6
    Drew Wiley
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    Re: Chemical age -- metol

    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.

  7. #7

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    Re: Chemical age -- metol

    Just checked my plastic container of Metol, I bought it in April 1992, so 30Ĺ 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.

  8. #8

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    Re: Chemical age -- metol

    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.
    Philip Ulanowsky

    Sine scientia ars nihil est. (Without science/knowledge, art is nothing.)
    https://www.flickr.com/photos/156933346@N07/

  9. #9

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    Re: Chemical age -- metol

    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.
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  10. #10

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    Re: Chemical age -- metol

    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

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