Relayer
Member
My understanding is DDX is buffered (Borax-Boric acid).
EDIT 2: Looking into this some more, I see that the MSDS for DD-X specifies (1) Boric acid (Michael R mentioned this), (2) Dimezone S instead of Phenidone, and (3) DTPA instead of DAPTA. So I'd say the patent was for an early formula which the engineers improved later. Based on quantity-ranges in the MSDS, I'd say this is similar to DD-X. Given this patent-formula and the MSDS, it wouldn't be hard to reverse engineer the present formula. Anyone want to try it?
Mark Overton
Be careful with that statement. Most common sequestering agents buffer in the pH range and DTPA is no exception (see page 6). Choosing a different sequestering agent can give you a different pH and buffer strength! Also note that the patent lists DTPA, while the MSDS lists DTPA pentasodium salt, the first one is a strong acid while the latter one is caustic (and much easier to dissolve). If pH is suitably chosen there is a good chance that no restrainer is needed.Sequestering agent isn't so important part of formula from patent. More interesting that developer omit any antifoggant (KBr, BZT etc)
Be careful with that statement. Most common sequestering agents buffer in the pH range and DTPA is no exception (see page 6). Choosing a different sequestering agent can give you a different pH and buffer strength! Also note that the patent lists DTPA, while the MSDS lists DTPA pentasodium salt, the first one is a strong acid while the latter one is caustic (and much easier to dissolve). If pH is suitably chosen there is a good chance that no restrainer is needed.
Yes, you right. If we omit DTPA or change it to other agent we need correct (decrease) amount of borax for required pH=8.5. This isn't a provlem
hmm ... may be. but I think that amount of DTPA relatively low for change buffer capacity.It's not only about pH, it's also about buffer strength! DTPA is a buffer at pH 8.5, if if we use less Borax in order to compensate for omission of DTPA, we create a much weaklier buffered developer.
That dev isn't exactly loaded with Borax either ...hmm ... may be. but I think that amount of DTPA relatively low for change buffer capacity.
The Australian MSDS documents often contain more detail. For what it's worth, here is an extract from it:
2. COMPOSITION/INFORMATION ON INGREDIENTS:
NAME
CAS No.: EINECS Nr.:
2,2'-OXYBISETHANOL (Diethylene glycol)
111-46-6 203-872-2
5-10 %
HYDROQUINONE
123-31-9 204-617-8
1-5 %
1-PHENYL-4-METHYL-4-HYDROXYMETHYL-3-PYRAZOLIDONE (Dimezone-S)
13047-13-7 235-920-3
0-1 %
DIETHYLENETRIAMINE PENTAACETIC ACID NA5
67-43-6 200-652-8
1-5 %
SODIUM TETRABORATE
1330-43-4 215-540-4
1-5 %
BORIC ACID
10043-35-3 233-139-2
1-5 %
WATER
30-60 %
POTASSIUM SULPHITE
10117-38-1
30-60 %
DENSITY/SPECIFIC GRAVITY (g/ml): 1.31 Temperature (°C): 20
pH-VALUE, CONC. SOLUTION: 8.7
How can those percents can be translated in grams, as a formula?
If you want to do some minimal searching: DD-X is disclosed in a patent where its (claimed to be superior) properties are discussed vis-a-vis HC/ HC-110 type developers. The reasoning for potassium sulphite is also given.
Why are you trying to find it? Odds are that you cannot replicate it, because special manufacturing processes are involved. Just make up FX-37.
Well, because DDX is equivalent with TMax Dev. TMax dev. is not anymore produced and I really like its shelf life. I had a 1L bottle of 1+4 for two years and even diluted it was working and developing just right. Also, I like the grain of TMax ( or DDX) and the shadow detail delivered.
Tmax developer is very good with Delta 3200, I used this combination to take photos inside of some of the National Trust properties in the UK and the negatives printed nicely.
Probably a forerunner leading up to Ilfotec DD/DDX rather than the actual formula of the product sold by Ilford.
Just make up FX-37.
TMax dev. is not anymore produced and I really like its shelf life.
It appears that the new US based holder for the license to make and sell Kodak branded photo chemicals will be supplying T-Max developer again. They were actually, beginning in 2019, the ones doing the contract manufacturing of most of the Kodak black and white photo chemicals for Kodak Alaris (initially) and then Sino Promise.
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