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Keith Tapscott. submitted a new resource:
Kodak D-25. - Kodak D-25.
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Yes, I tested it over Easter, it's not bad at all,very fine grain, lowish contrast negatives though which weren't really ideal as it rained nearly every day I was back in the UK !! The weather made it difficult to tell how it really behaved tonally, but I felt it wasn't worth taking it any further.
I think it's wrong for modern films, I tested Foma 100 & Delta 100, they both have good inherent fine grain anyway.
This is similar to a diluted form of Patrick Gainer's Metolol or Rodinal using Metol.
It's not really similar at all, (well not to any form of Rodinal)
The Sulphite content is more than ten times higher and the pH is close to 7 whereas old Classic/Rodinal must be nearer 9-10 (that's a very quick guess, but it should be roughly 11.8 before dilution).
It does show quite nicely how Kodak switched techniques though to high sulphite levels for fine grain
Similar only Ian.
It is, of course, lower in pH and higher in sulfite, but it is basically Metol and Sulfite which is an analog of Rodinal and Patrick's formula in substance and probably somewhat in function.
Actually Ron, it's a lessson on the extremes of a simple developer, one end is higher pH and acutance, the other with a low pH is very fine grain.
In the case of Metol the middle ground, as in most practical is D23. But the there are good reasons it's not used by many.
I'm nearly ready to do a flow chart of how some Kodak developers evolve. If we co-ordinate, I think the magic Triangle will make sense.
After all of those years in the lab, I can say that "I know that!" and mean it. And that I know what was being done to lay the grounds for a more effective compromise.
If you view the "triangle" of developer properties as flat, then by applying some new technology it can become effectively a "pyramid" bringing the points of the triangle closer in and making a developer that improves all 3 properties at once.
Hey, applying 3 dimensions on a 2 dimensional object will get you kicked right out of Flatland. And don't go talking nonsense about that ficticious Spaceland place. I'm never going to believe it exists!
Well, if you don't believe me, then I guess you will just have to wait and read about it somewhere else.
Buckaroo Banzai forever!
I hear they have a 2 for 1 sale on that book at K-mart.
If you act quickly, you might still be able to pick up a couple.
My tongue is now plugged in!
Having long been addicted to replenished D23, I tried D25 several times but it was just too soft, and mushy for my taste. Kodak does suggest using half the bisulphite; but I never tried it. D25's replenisher, DK-25R, however, is what I use to replenish my D23.
I'm interested in replenished developers, D23 being one of them. How do you ripen a new batch of D23? and how much replenisher do you use for each 80 square inches of film developed in D23?
The formula I posted shows bisulphite, while a Kodak formulary that I have shows metabisulphite. Kodak also suggest that D-25 is used at 25*C (77*F) and to use the development times for undiluted Microdol-X for 20*C (68*F).
I don`t want to make it, I was simply curious how it performs with modern B&W films, hence my question if anyone has used it.
Sorry Ron, but I don`t see the connection between D-23, D-25 and Rodinal.
Bisulphite is mainly Metabisulphite, US ambiguity.
Kodak in Europe seem to have had to adjust between the mixed Bisulphite/Metabisuphite sold as Bisulphite in the US and the pure Metabisulphite sold in Europe, it may really be differences in manufacture.
I let the ripening take care of itself. I replenish with 24 ml DK-25R per 80 square inches.
I should have added D-76 with only Metol.
I only mentioned from your OP, Rodinal and Patrick Gainers attempts at a Metol equivalent.
These are sulfite developers with alkali and Metol. They represent the gamut of what can be achieved by this combination by varying basically 3 ingredients to optimize for either 2 of the 3 properties we want from a film. Vary the pH to a higher value and you approach Rodinal or Patricks formula and etc, especially if you use it very dilute as Rodinal is. Ian caught my analogy right off in another post. No need to repeat it here.
My bottom line is that with a few basic ingredients and a small set of experiments you can play with the developer and get it to do most anything you want. When you add other, more exotic ingredients, a point I have made elsewhere, you push outside this "triangle" and can get some vastly improved properties.
But you can also increase the complexity of finding a combination that works well or better.
The answer to that is yes and no, depending on what you have done in the past with these new compounds. In fact, some of them would be new to you but not to me.
And there's the catch!
Thanks for the replies, I wont bother trying D-25.
Kodak DK-25R is used to replenish D-23.
Water 125F or 52C - 750.0 cc
Metol (Kodak Elon Dev Agent) - 10.0 g
Sodium Sulfite, dessicated - 100.0 g
Sodium Metaborate (Kodalk) - 20.0 g
Add cold water to make 1.0 litre
Use 3/4 ounce of replenisher for every 80 square inches, discarding some developer if necessary.
(Taken from Amphoto's 1972 Black/White Processing DATA BOOK)