Replace PPD by CD-3

Gerald C Koch

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No, you need to divide the MW of the CD-3 by 2 in your calculation. What developer are you trying to modify? There are other things to consider besides MW. There are two base units considered in their MW. Usually the MW of such things as CD-3 are given as the sesquisulfate.
 
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Alan Johnson

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Thanks,

I would like to make Sease no1 superfine grain developer equivalent.

paraphenylenediamine (base).............10g
Sodium Sulfite (anh).........................90g
Water to..........................................1L

I don't think Photoformulary.com can ship PPD outside the US any more so in many countries it will now be unobtainable.
 

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Yes, I agree with Ian. Good choice and less toxic and less subject to aerial oxidation. However, as CD-2 comes as an acid salt, you will have to adjust the pH to the correct value. In this case I have no idea what that would mean. Maybe the Crawley formula would suggest something.

PE
 

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What if you tried to replace it with Paracetamol instead its sold at the local pharmacy as Tylene or Paracet I think.

I've been eyeing Sease #1 myself, a treue superfine grain develolper is good for modern-day film in oldtime cameras, to get ISO down from todays 100 - 200 ISI to yeesterdays 25 - 50 ISO, and the superfine grain is free!

Erik
 

Ian Grant

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Activity is not in step with Molecular weight, also Sease 1 is the worst of the series, the commercial out come was ND-3 which is a variant of Sease 3.

Ian
 

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Whatabout a replacement of PPD with Vitamin C?
To turn Vit C into Ascorbate I'd offer the following :

water 100ml
5 gram Soda
15gram ascorbic acid

Add 700ml water
90gram sodium sulphate
top up to one litre

The first step will see to it that the soda reacts and turns the Vit-C into ascorbic
the rest mimics Sease.

Just a suggestion, ascorbate is a known finegrain developer that dissolves silver, just as it should, but maybe too active?
 

Keith Tapscott.

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Not CD2 or 3, but there is a formula I posted a while back which uses CD4.
(there was a url link here which no longer exists)
 

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You call PPD a color-developer?

Not a word spelled about that in my copy of Die Neue Foto-schule I, Die Technik, Hans Windisch, 1954!
But Hans has this pegged down firmly as a fine grain developer and quotes Sease III formula which is a little different from Sease I....

Erik
 
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Photo Engineer said:
Ascorbic acid is not in any way similar to PPD or CD-2.

PE
Click to expand...

Granted but now PPD, CD-2, 3 and 4 are already floating in this thread, what are the similarities & dis-similarities between those already?

A little rundown on developing agents, and not just links, please!
 
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Alan Johnson

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From Anchell & Troop p 67 "The amount of glycin in Sease 1,2,3 & 4 was respectively,none,1g,6g,and 12g.As glycin is increased,speed goes up,but fine grain goes down."

To get the finest possible grain I would like to make the equivalent to Sease no 1 but I would like to know if to use 214.7 parts CD-2 or only half that,to replace 108.1 parts PPD.

In Sease 1 both sulfite and PPD are grain solvents ,it seems to me that other additions like glycin or hydroquinone are not and are mainly there to speed things up a bit.
 

Ian Grant

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Don't dismiss CD-3 too quickly, it's a weak developing agent but Kodak did publish a Super Fine Grain Developer using it in a Patent in 1940. They overcome the weaker activity by using Carbonate as well as Sulphite.

The 1940's Kodak Patents for developers are quite interesting as they show some rather interesting avenues of research, Kodak had a set portfolio of developers etc it was harder for them to change the line up than smaller companies, so we only see gradual new introductions or replacements.

Ian
 

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Ok, Ascorbic Acid is a normal rather benign B&W developing agent. It has no special properties, but does often decompose unexpectedly and so the developers should be tested before use for potency.

PPD is a very slow acting developer that gives fine grain and often low speeds, depending on formula. It is rather toxic and not too soluble. It tends to oil out and form black tars.

CD2, 3, 4, and 6 are faster acting than PPD but similar in some regards. CD4 is the most soluble and CD6 and CD4 are the most active. CD2 is more toxic than 3, 4, or 6 and less soluble. But it is less toxic than PPD. I would pick CD2, CD4 or CD6 to design a new B&W developer but would not use any of the existing formulas. There were several improvements on the books at EK that never saw the light of day. Go for it!

Ian's post above is quite correct and I am aware of work in that regard and some that went beyond the patents.

PE
 

Ian Grant

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PPD is a weak colour developing agent, even weaker is p-aminophenol

My "The New Photo School" is in English 1938 First 1- 10,000 Edition, although I also have a German 1944 edition.

Ian
 

nworth

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Ian Grant said:
Activity is not in step with Molecular weight, also Sease 1 is the worst of the series, the commercial out come was ND-3 which is a variant of Sease 3.

Ian
Click to expand...

DuPont ND-3, and Defender 15-D (also Sease NH-3) are similar developers falling somewhere between Sease No.2 and Sease No. 3. They contain more sulfite than the regular Sease formulas and 2 grams of glycin (compared to 1 or 6 for Sease 2 and 3). These developers have a good reputation for a compromise between ultra-fine grain and good sharpness. I understand that Sease No. 1, aside from drastically reducing film speed, produces rather mushy results. I've had good success substituting CD-2 for PPD in a couple of formulas, although not these. CD-2 seems give somewhat more film speed than PPD. CD-3 sounds like an expensive option.

DuPont ND-3 Fine Grain developer
For 35 mm film, sheet film, and similar negative material
Water (52C) 750 ml
Sodium sulfite (anh) 80 g
Paraphenylene diamine base 10 g
Glycin 2 g
WTM 1 l
Give negative 2 to 3 times normal exposure. Develop old film 10 to 17 minutes at 20C.
 

Ian Grant

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A big issue with developers is that manufacturers like Ilford, Agfa and Kodak could only sell so many types otherwise the sales & marketing was self defeating.

So there's a vast number that never made the cut archived away. Sometimes other companies beat them to it with Patents, I'm fairly sure that's what delayed Xtol (or an Xtol type developer) as there was an early 60's US Patent held by a Swedish company and Xtol only appeared after that had expired.

Sandy King's Pyrocat HD (and MC) are close variations of earlier Ilford Patent & a commercial developers, although used at much higher dilution and arrived at entirely independently. Kodak patented a similar Pyrocatechin/Ascorbic developer in the 40's but again ratios differ. There's only so many combinations ratios etc but many have been neglected or pushed back.

Kodak spent years after it's introduction trying to improve D76, but as it had become a standard it was near impossible, they had to stick to close variants, that's still the case today with both D76 & ID-11 only th buffering differs from the original. Others did improve it - Agfa/Agfa Ansco and Adox (Dupont) but then they were entirely different dvelopers.

Ian
 

Ian Grant

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All the same company ultimately as Dupont took over Defender and Dr Sease designed them all

There was a pre WWII link with Ilford, Dupont supplied them film base but there was also some shared research, and Dupont's first Varigram was based on Ilford Multigrade, although actual production of Ilford's product was delayed because the UK was already at war unlike the US.

Ian

 

eclarke

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Are you in the US? I just got 2 pounds of ppd from Formulary (as an aside, I use a lot of this and the stuff I just got from them is the best I ever bought, finely milled and dissolves very well)...Evan Clarke
 

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As has been noted, these developing agents vary so much in activity that there is no molar equivalency. Also, some formulas call for the free base and some of you are discussing the acid salts which will give a much lower pH than the free base. So, please be careful.

Activity is roughly CD4, CD6, CD2, CD3 with PPD somewhere in the middle of that, all things being equal. They are ranked roughly highest to lowest in activity from my own personal experiments of the 4 Color Developers. I have done no process work with PPD.

PPD's silver halide solvent ability is weak if it even has any. I have really forgotten the data, but it did not stand out as did Sodium Sulfite. In fact, PPD must be used with Sulfite to get much activity at all, even if you adjust for pH. It achieves the fine grained nature by being so slow and gentle. In fact, HQMS (Hydroquinone MonoSulfonate) is similar in that it is a fine grain developing agent by virtue of being slow. It is used in E6. Those that mistakenly use HQ in E6 first developer thereby lose this property.

Going off on a tangent is not bad or good when designing a developer and can be very rewarding, but it is often complex and filled with trial and error. It is an art.

PE
 
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