High Acutance Develper

[Ian Grant]

In his book "Photographic Processing Chemistry" (1974 Focal Press), L.F.A. Mason lists a typical High Acutance Developer.

This may possibly be the formula for Hyfin, which was Ilford's High Acutance developer, available from 1961 until the early 1970's. Mason calls it a typical formula:


High Acutance Developer

Metol 0.5g
Sodium Sulphite (anhyd) 5g
Sodium Carbonate (anhyd) 5g
Water to 1 litre

Development times 15-25 minutes
Requires a minimum of 600ml of chemistry per 35mm or 120 film.

Mason notes that additions to the formula have been proposed, either 0.1g/litre Potassium Bromide or 5ml of 0.0001% Potassium Iodide solution. (He may be referring to other similar formulae like FX-1 etc)


Hyfin was sold in packets containing 5 sachets of developer each one making up 600ml of solution. I have two packets of Hyfin & will weigh the contents of a scchet next time I'm in the UK.

Hyfin instructions were:

Pan F & FP3 - 18 minutes @ 20°C
Continuous agitation for the first 10 seconds then 5 seconds every minute.
Gives 1 stop more effective film speed



In the early 60's there were 3 High Definition devopers availabe in the UK, lford's Hyfin, Kodak's High-Definition Developer & Johnson's Definol.

It's no co-incidence that Hyfin & HDD are very similar to Beutler's High Definition developer, sold as Neofin Blue, and another similar developer is Crawley's FX-1 formula.

The major differences are that Beutler has 1g Metol/litre & Crawley's FX-1 only 2.5g Carbonate + 15ml 0.0001% KI, compared to the formula above. The decrease in the Metol level compared to Beutler is likely to increase the edge effects & acutance further.

The addition of Potassium Iodide is likely to have little or no effect now as most modern films contain far higher levels in their emulsions, particularly Tmax & Delta films. It may have been more important with certain films Crawley speculates that it was needed in HDD for Pan-X

Mason would have known Crawley and his work, Ilford began manufacturing his chemistry for Paterson around 1963.

Ian

[Tom Kershaw]

Pan F & FP3 - 18 minutes @ 20°C
Continuous agitation for the first 10 seconds then 5 seconds every minute.
Gives 1 stop more effective film speed

Information about ILFORD Perceptol tends to suggest film speed is lowered so it is interesting that this developer apparently gives a 1 stop increase in effective film speed. At first consideration, I'd have thought exposing Pan F Plus at E.I. 100 would result in rather high contrast.

Tom

[Ian Grant]

The high level of Sodium Chloride used as a restrainer & silver solvent in Perceptol & Microdold-X greatly reduces the effective film speed.

Ilford claimed a speed increase for Hyfin, but the 1 stop is more likely with FP3 or FP4, I'd have to agree that it might not be as much with Pan-F. The solvent effect of Sulphite in D76/ID-11 does drop the effective speed, so a developer like Adox Borax MQ with less Sulphite give half a stop more speed.

With such a low level of Metol these Beutler type developers are compensation so shouldn't be over contrasty they were designed to be used with films like Pan-F & FP-3/4, and Kodak tailored its HDD for Pan-X etc. The low level of Sulphite allows greater effective film speed, remember we use high sulphite developers like ID-11/D76 as our benchmark.

Ian

[Tom Kershaw]

Originally Posted by Ian Grant

The high level of Sodium Chloride used as a restrainer & silver solvent in Perceptol & Microdold-X greatly reduces the effective film speed.

Ian

If I recall correctly there was some debate here on APUG as to whether the formula given in the 'Film Developing Cookbook' as Microdol is correct. Has a Perceptol or Microdol-X type formula actually been published?

Tom

[Ian Grant]

There's no debate on the three main constituent parts in Microdol-X or Perceptol but we don't know the trace additives for sure. They are known to be based on D23 with Sodium chloride, as the MSDS sheets clearly used to show Metol, Sulphite & Sodium Chloride - mistakenly listed a Bromide for a while on the Perceptol sheet.

D23 with 25g Sodium Chloride behaves like Perceptol.

Ian

[Photo Engineer]

Interestingly, the formula in the OP is rather ancient compared to the HDD formulas being worked on in the latter days of B&W R&D at EK. It is also interesting to add here that according to a note I made to myself over 30 years ago, and which I just found yesterday, there are two ingredients in Microdol X that are not listed in the MSDS. I assume that is due to the trade secrets law or whatever. Perhaps they are omitted due to low concentration. I do not have the formula, just that old notation.

PE

[Ian Grant]

You could enlighten us Ron, what routes were being used for HDD ?

Ian

[Photo Engineer]

Originally Posted by Ian Grant

You could enlighten us Ron, what routes were being used for HDD ?

Ian

Well, to clarify something I posted earlier, A&T do describe the extra ingredient(s) in Microdol X, as described in the patent by Henn. I wanted to dispel that mystery.

Now, on to HDD developers. As I have explained before, electron pump or electron transfer agents were at the top of the list for investigation. I have already implemented that in Liquidol for papers. They give long lived developers with good activity and high capacity. For films, they can give High Definition by alteration of the basic formulas.

Iodide was seen to be an inhibitor of edge effects kind of like a buffer against them taking place. With higher iodide levels this became more apparent, and therefore HDDs with iodide were viewed as being somewhat passe.

In fact, on the triad of Sharpness, Speed and Grain, it was found that at best you could strike a happy medium getting 2 out of 3, but getting a slight optimum of #3 by the right formula and this is what an HDD tries to do. It gets Sharpness at its best and then gets the best of the other 2. This is achieved by moderation in the activity of ingredients that control the other two. For example, Sulfite controls grain, is a simple statement but can serve as an example. At high concentration, you lose sharpness but improve grain.

I believe that Kodak has this triad mapped out in a graph on their web site along with developers placed on the chart to show how they affect these three characteristics of film. If you look at the chart, and compare with formulations, you will see what I mean in the above.

In the final analysis though, there is no magic bullet and we cannot go backwards in time and expect improved results, especially with modern films. This was the bottom line with our R&D.

PE

[Tom Kershaw]

PE,

Are there any general principles that might dictate whether more modern films such as TMY-2 or Delta 100 may respond to a greater or lesser extent to changing developer compared to conventional grain films?

A&T makes a statement that new technology films are only really for the benefit of the manufacturer; but as the vast majority of my film usage has been with designer grain films, I don't really have anything to compare their statement to.

Tom

[Lee L]

Originally Posted by Photo Engineer

I believe that Kodak has this triad mapped out in a graph on their web site along with developers placed on the chart to show how they affect these three characteristics of film. If you look at the chart, and compare with formulations, you will see what I mean in the above.

PE

http://www.kodak.com/global/en/profe...?pq-path=14053

Lee