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DK-25R with teaspoon method

BetterSense

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Aug 16, 2008
Messages
3,151
Location
North Caroli
Format
35mm
Does anyone have a volume-based recipe for DK-25R?

I just mixed up some D23 using 2 level teaspoons of metol and 4 level tablespoons of Sodium Sulfite in a liter of water. I

I can't find a recipe for DK-25R, however, and I don't know how dense sodium metaborate is.
 
!0 gms metol, same sodium sulfite, 15 gms Kodalk. I use 1 TBS metol (10.5 gms) and 1 TBS - 1/8 tsp of Kodalk to make my DK25R. Been doing it for years. As we say here in Northern Virginia, "Close 'nuff fur gummint work."

I am down to my last jar of Kodalk before going to Sodium Metaborate.
 
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By the way, the old darkroom rats would make up "D23" by just mixing an ounce of metol to a pound of sodium sulfite in a gallon of water.

It's a couple ounces heavy on the sulfite, but for souping with D23 1:1 or 1:3 I can't imagine it would make much difference.
 
Remember that the volume / weight values can vary by +/- 10% depending on batch of chemistry due to crystal type. This means that you may get powder from one company and large crystals from another. So, to be a "real" photographer scratch mixing chemistry, volumetric measure is the worst way to get good results.

PE
 
I didn't want to mix up a whole gallon, though. I actually only had wine bottles so I mixed up 750mL, which made the math a bit tricky.

1.5tsp. metol, 3tbsp. SS. to make 750mL D-23

Then I mixed up 333mL of DK-25R

1 tsp metol, 1.5 tsp kodalk, 4tsp SS to make 333mL DK-25r.

I should really get a scale, but all the electronic kitchen scales only go to +/- 1g.
 
If you wish to do scratch mixes, you need a scale or balance accurate to 0.1 gram. I suggest you use that to damp out your variability from batch to batch or to use off the shelf chemistry.

PE
 
Anyone suggest a starting time for Tri-X at 250? It's hard to find data for D-23; there's only one entry in the MDC and I don't trust the MDC.
 
BetterSense said:
Anyone suggest a starting time for Tri-X at 250? It's hard to find data for D-23; there's only one entry in the MDC and I don't trust the MDC.
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I have long used eight minutes at 68 F at EI 200. It gives a good, gutsy neg with loads of shadow detail, good highlight separation, and still printable highlights. In a very contrasty light--if high tones are important, you might wish to cut back a bit--otherwise, let 'em fall where they may. I use standard ASA agitation.

Regarding P.E.s comments. I agree with him. But I mostly use all the same few chemicals and, just for kicks, I check my spoon measurements against a scale once in a while. I have a powder scale for reloading ammunition: it is accurate to 1/10 grain. Biggest problem for this math-challenged former history major is converting those @#$ grains to grams (groan).
 
I used eight minutes for my first roll. The negs look pretty good so far; plenty of density. I mis-spooled them on the reel again though and lost the last foot of my roll. I have the hardest time with 35mm film.
 
Anscojohn;826431 Biggest problem for this math-challenged former history major is converting those @#$ grains to grams (groan).[/QUOTE said:
Use Google!

You can type conversions into the search engine and let Google do the conversion for you. For example, type "convert 50 grains to grams" and click on search and Google will return with "50 grains = 3.2399455 grams". Easy!
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Simply go here pick the from and too measures, punch in the amount, and get your results, lets you go both ways.....
 
Wolfram Alpha is better now for complex unit conversions. You can ask insane things from Wolfram Alpha and it will just tell you.
 
[I mis-spooled them on the reel again though and lost the last foot of my roll. I have the hardest time with 35mm film.[/QUOTE]
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Give it time. You'll get the hang of it. Most do.

One thing about temp control with D23: Since it has just one developing ingredient, and since metol is very linear, time temp/charts work fine. I copied mine from an old Ilford Encylopedia of Photography.

And be sure to put the replenisher in your jug whilst the film is developing. Then pour the D23 back in when development is finished. Discard any excess D23.

If the D23 gets too gunky-looking for your taste, filter it through a coffee filter. I have heard of people using a liter of D23 for more than a year or so and it got to looking like swamp water with no apparent effect. But with 3/4 liter and just 1/3 liter of DK-25R, you should be o.k in that.
 
Go to a gun store and buy a cheap powder scale or balance. They come in at under $50 and can weigh in grams or grains.

PE
 
Photo Engineer said:
Go to a gun store and buy a cheap powder scale or balance. They come in at under $50 and can weigh in grams or grains.

PE
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Just don't mistake your metol for Bullseye
 
I'm sure it's fine. I just mixed up a new batch tonight using the fancy electronic scales at work; I'll just put 5 more grams in.
 
If Google was being properly correct, it would have said "50.000000 grains = 3.2300455 grams". We can use one fewer significant figures in the grains.
In 1973 when I wrote "Kitchen Tested Soups" for Petersen's, I showed eamples of the kind of variation one might expect in volumetric measurements, both by weighing 10 samoles of each of the chemicals I used, and by demonstrating photographically the effects that variations very much greater than those I measured might have on volumetrically measured D-76. I went through the arguments that PE voiced much later. Being very precise in measurements won't eliminate most of our failures, and even 10% measurement errors won't cause most of those failures. Common sense should prevail over uncommon nonsense. If you don't know which of your measurements are critical for accuracy, it's time to do some experiments or at least some study. Even if you weigh everything to the milligram, that is useful knowledge.
 
gainer said:
If you don't know which of your measurements are critical for accuracy....that is useful knowledge.
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After 30+ years as a construction contractor, I think this is one of the (many) universal general truths I learned. Just about anyone can make a very good home-handyman job. A true craftsman can do it with amazing speed. One of the reasons why is he inherently knows what level of precision & accuracy is needed for every component, and not everything has to be NASA ready to do a perfect job.

On the teaspoon method, I'm limited by my primitive precision scale and something like Phenidone (used in small quantities ususally) is 53 "nip" teaspoons per 2.5grams. Coinage makes for cheap precise counterweights. (yes, I could buy a scale, but that's too easy)
robert
 
I read Gadget Gainer's article years ago and I believe I still have the mag in a box downstairs. When ye olde darkroom rats would say the formula for D23 is an ounce of elon and a pound of sodium sulfite in a gallon of water, the sulfite was a coupla hounces heavy. I guess if they used D23 1:1 or 1:3 it didn't matter much. I, however, have used spoon measures for years and get my D23 and DK25R "close enough for gummint work, it seems to me." In several ways, I think D23 is very forgiving of we poor mortals. But I do have scales and I do check every now and then.
 
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