Can You Make A High Acutance Developer Using Phenidone?

Snapshot · Sep 18, 2007

Hi All,

Has anyone has any success in developing a high actuance developer using phenidone? I've been experimenting with the following...

Water....................750ml
Sodium Sulphite.......20g
Sodium Carbonate....15g
Ascorbic Acid...........4g
Phenidone...............0.1g
Water to make.........1,000ml

I dilute for development using 1 part formula and 3 parts water. The results look good as the grain is quite moderate, low base fog and the development time is about 9 minutes for most 100 ISO films. It appears relatively sharp when compared to XTOL but I haven't had an opportunity to compare it against other acutance developers, like FX-37. However, I could use advice on how to improve or to avoid any problems that the above formulation will have.

It's my understanding that it's difficult to make a phenidone developer that's sharp. Anyone else had any sucess (or failure) in making a phenidone acutance developer?

Xmas · Sep 18, 2007

Try more dilution 1:10 or 1:20 more time, less agitation.

Phenidone is a Metol analogue so any high actuance Metol formula should work with a prorata P for M substitution - sort of.

Noel

jim appleyard · Sep 18, 2007

You may get some info from pg 24 of "The Film Dev. Cookbook". It has a paragraph that talks about the sharpness of PQ negs, FWIW.

Snapshot · Sep 18, 2007

jim appleyard said:
You may get some info from pg 24 of "The Film Dev. Cookbook". It has a paragraph that talks about the sharpness of PQ negs, FWIW.

Yes, I reviewed this section and other sections of the book. In summary, the consensus was that PQ developers are harder make into acutance developers due to their regenerative characteristics. I was looking for guidance to formulate a sucessful formula but if it's a rat hole, I rather devote my efforts to formulating MQ or straight Metol acutance developers.

Photo Engineer · Sep 18, 2007

There are far better methods, but I prefer not discussing it right now until I do some work of my own. The developer you have above is good enough for starters, but there are better.

PE

Snapshot · Sep 18, 2007

Photo Engineer said:
There are far better methods, but I prefer not discussing it right now until I do some work of my own. The developer you have above is good enough for starters, but there are better.

PE

Well, if I'm in the general neighborhood, I'll keep plugging away. Any advice, in the future or otherwise, will be appreciated. Thanks for your response.

Alan Johnson · Sep 18, 2007

PC developers without sulfite,eg, PC-TEA, P-sodium ascorbate-Borax will start working with reasonable development time at about pH 9. IMO, using the classification of acutance developers given in the tables on p55 of the Film Developing Cookbook,they can all be called acutance developers. Making them (without sulfite) more alkaline using metaborate or carbonate makes them more grainy.There is not much discussion if it increases the acutance.
Adding sulfite complicates it.

eclarke · Sep 18, 2007

I am a big fan of FX37, is there something you don't like about it??..Evan Clarke

gainer · Sep 18, 2007

I am looking at the frame of my monitor where it adjoins the lighter background and am seeing an edge effect such that the background immediately adjacent to the frame appears lighter than the background a little farther away. This is not a photograph. Would I want a photograph of this area to show even more pronounced edge effect? Why would it not be sufficient to have the photo show the most abrupt possible transition from edge to background?
When we test an audio amplifier, we want it to have the cleanest possible response to a square wave. We used to try to doctor up rounded leading and trailing edges by integration or differentiation through RC networks. It is generally not possible to remove both amplitude and phase errors, so we wound up with some pretty awful amplifiers. Both amplitude and phase errors are possible in lenses. Are we saying that we can correct them by the proper developer? I have seen some pretty bad photos about which the only good thing one could say was "My, what exemplary edge effects."

If we look only at the amplitude part of the Modulation Transfer Function, we might say we can make the curve flatter by certain development tricks. We are fond of saying that resolution and acutance are not necessarilly the same, but increasing acutance artificially can lead to reduced resolution, which you will see in things like fence pickets and the like.

It's a sign of advanced age, I suppose, but I cannot remember what got me on this rant. I'm getting off it now.

Snapshot · Sep 18, 2007

eclarke said:
I am a big fan of FX37, is there something you don't like about it??..Evan Clarke

Actually, I'm a big fan too. I've recently come to the conclusion that actuance developers are the way to go for my type of shooting. I mainly use FX-37 for my development needs as well own pyro developer formula. Occasionally, I soup APX in Rodinal for the special look it has.

I'm not discontented with FX-37, I merely experimenting to see what I can come up with on my own. The pyro formula was a pleasant surprise but I'm trying to come up with an actuance developer that uses phenidone. If I fail miserably and I have to continue to use FX-37, then I won't be unhappy at all. I'm certainly not qualified to succeed at any rate.

Alan Johnson · Sep 19, 2007

FX-1 gives highest acutance, works well with old films,eg, Adox/Efke25. Here is an FX-1 copy using phenidone,I have tried the metol version of it only:
Phenidone 0.1g,Sodium Ascorbate 5g, Sodium Carbonate 2.5g, water to 1L (working solution).FX-1 gets its acutance from metol exhaustion, in the copy the phenidone is regenerated and does not exhaust,I believe.
It is possible to estimate the acutance effect of a developer by using Tri-X or Plus-X to photograph a gray card on top of a black card and making a 10x enlargement of the edge.A lighter line appears at the edge on the gray side of the print.
I have done this with Plus-X and half-strength FX-1 90min 68F and Plus-X and PC-TEA 1:200 120m 68F.The effect is much less with PC-TEA but still present.The FX-1 copy might be better.

gainer · Sep 19, 2007

Where did the idea originate that Phenidone regenerates but Metol does not? Metol was used in experiments reported in "The Theory of the Photographic Process" to show the power of ascorbic acid to regenerate Metol. Your developer, with the metol and ascorbate, is surely regenerating the matol.

Much less Phenidone is required to do the job of Metol, which is a good thing, since Phenidone is much less soluble in water than is Metol. Phenidone is less restrained by bromide, but I'm not sure if that applies when Phenidone is used in combination with another agent such as ascorbate, hydroquinone or catechol.

In order to dissolve Metol in glycol or TEA, one must remove the H2SO4 that makes the Metol base soluble in water. A simpler way to compare PC-TEA with a Metol analog would be to dissolve the ascorbic acid in TEA and add the solid Metol to the working solution.

The ascorbate itself change the nature of the edge effects from those of PQ or MQ because its oxidation product is acidic, whereas that of hydroquinone is basic. This local change in pH on one side of the light-dark boundary should affect the results obtained from minimal agitation techniques.

It would be well, while you are searching for the edge effect, to expose a resolution chart to see what happens to fine lines.

Photo Engineer · Sep 19, 2007

The actual development of silver halide produces enough protons to swamp a poorly buffered developer. A well buffered developer can overcome this effect. Remember that AgBr + Developer -> HBr and DOX. The hydrobromic acid ends up as NaBr in high alkali but not in weak unbuffered alkali.

So, dilute developers will work differently than concentrated developers as far as pH effects, but both HBr and NaBr will cause edge effects being retardants of development and they do it imagewise, or as a result of poor agitation (bromide drag).

For this reason, edge effects are often hard to assess as to source unless you measure the actual local concentration of development products as can be done with microprobes. I have done this with micro surface pH probes to detect pH during development for example.

As for phenidone, it is so complex in reaction that there is still dispute going on as to its reaction products. It is clear that it does not react with sulfite like Metol or HQ. It also is less base dependant and decomposes in sealed oxygen free alkali solutions.

It is also clear that it is not completely regenerated after oxidation. It can undergo a host of reactions, one of which regenerates a phenidone and an inert by product, others which generate inactive species and etc. So, I would hesitate to give an answer to any question on what phenidone does when oxidized.

As for other varieties of phenidone, they are just as poorly understood and less well reported in the literature.

BTW, this all comes from Mees and James but with my 'non chemical' translation for everyone out there.

PE

Snapshot · Sep 19, 2007

I think I'm in over my head for the time being. I guess it's FX-37 for me then.

Alan Johnson · Sep 19, 2007

Sorry for any lack of clarity.I meant metol in FX-1 is not regenerated,sulfite removes it. Phenidone in the copy is regenerated by ascorbate.
My explanation of edge effects is as follows:
The acidic reaction products of ascorbate change the 'fringe' effect due to diffusion of reaction products but not the 'border' effect due to diffusion of developer from unexposed areas of film.Mackie lines are white on the print, they are due to the film receiving extra development resulting from lateral diffusion of developer from unexposed areas of film,they are 'border' effects.
I dont see how the film can get extra development due to acidic reaction products,the 'fringe' effect may be present but has no detectable effect.

Photo Engineer · Sep 19, 2007

Alan;

Your explanation is incomplete.

An edge effect is caused by a pH drop in the center of a developed area, bromide release (or other halide) in that same center of development and exhaustion of developer (even if it is regenerated to some extent and somehow).

These 3 causes will decrease development in the center of a developing area, while development at the edge is increased due to inward diffusion of fresh developer. Outward diffusion of development byproducts inhibit development on one side of the edge and inward diffiusion accelerates development, causing the well known and typical 'ears' in a slit exposure.

My point about phenidone is that it is less sensitive to pH effects and therefore would, on average, give less edge effect due to pH changes. Other than that, phenidone is no different than other developers.

As for ascorbic acid, Mees and James are silent on the oxidation products, but since it is an acid itself, then if the solution is well buffered it should have no serious effects.

In addition, these edge effects must be adjusted to differ according to size so that the developer is optimum at any magnification by altering not the edge effects, but rather the contrast of the image. In other words, the micro vs macro contrast must be made to vary as a function of the edge effects produced at different sizes of images.

I have a rather lengthy post here somewhere on the topic and it includes curves for this from an article by M. Kriss.

PE

nworth · Sep 19, 2007

Photo Engineer said:
... As for phenidone, it is so complex in reaction that there is still dispute going on as to its reaction products. It is clear that it does not react with sulfite like Metol or HQ. It also is less base dependant and decomposes in sealed oxygen free alkali solutions.

It is also clear that it is not completely regenerated after oxidation. It can undergo a host of reactions, one of which regenerates a phenidone and an inter by product, others which generate inactive species and etc. So, I would hesitate to give an answer to any question on what phenidone does when oxidized. ....

PE

These facts seem to argue that a high acutance phenidone developer is certainly possible and may work very well, indeed. But formulating it may not quite follow the usual rules; we need to be guided by the principles for forming the Mackie line. Phenidone, by itself, is a very powerful but low contrast developer. To me, that argues against it. After all, the Mackie line is a contrast effect. But the lack of full regeneration means that local exhaustion will be more complete during development, which is a plus. I'm not sure how sensitive phenidone is to bromide concentration, but that could also affect the acutance, since development may not be inhibited where it needs to be. I'm not sure what part physical development plays in an acutance developer, but sulfite concentration can have a large effect on just how much happens. Physical development will preferentially take place onto the denser parts of the negative, while sulfite dissolves silver (a little) all over. It could either enhance or detract from acutance. Phenidone's different sensitivity to sulfite may have an effect here, although the plating effect of physical development is different than the chemical development caused by phenidone. A co-developing agent may be valuable, but what and in what concentration is a question.

The formula given at the top looks like a decent start. My thinking runs toward a bit less sulfite and dilutions of 1+5 to 1+9. A buffer for somewhere in pH 9 - 9.5 range may help, but may not be necessary. You can work out the buffering capacity of the dilute carbonate vs. the expected acid from development, which is very small. The buffering will probably be more important for the ascorbic acid than the phenidone, as long as the pH remains high enough for the developing agents to be active. (That introduces an interesting possibility: development releasing HBr, reducing the local pH as well as increasing bromide concentration, reducing local developer activity, and thus increasing local contrast???)

Photo Engineer · Sep 19, 2007

Nworth;

You are essentially correct.

I would note one thing. Since phenidone is not as sensitive to pH changes, the high dilution will probably not cause the same magnitude of edge effects as it would in an MQ developer for example, at least that portion related to pH effects.

As for halide effects, I can't really say.

I think that your guesses might work, but I would start with another formulation more like what I have seen worked on at EK by Lee, Haist and others. There are so many novel ways of getting HA that have never been mentioned. Basically though, I stay away from ascorbic acid.

One other thing to remember is that there is an induction period in MQ developers, but none with phenidone. This is also an important point because development with phenidone follows the diffusion front and development starts instantly, whereas MQs follow the front, but don't start developing until the induction period is over.

This changes the fundamental behavior of any phenidone type developer vs an MQ developer. In what sense, I really cannot say. I know there are effects, but this is one I have not studied or read up on.

PE

gainer · Sep 19, 2007

I agree. The subject has so many ins and outs that I am reminded of an old stand-up comedian who pretended to be a professor. He came on stage wearing a tuxedo and sneakers. When asked "Why do you wear sneaker?" he said "That is a two part question. The first part, Why, has been asked by philosophers throughout the ages and none has found the answer, so I will not try. The second part is "Do you wear sneakers?" and the answer is obviously "Yes."

Why are there edge effects?

So when someone says such and such is a fine grain, semi-compensating, high resolution, high acutance developer, I might take his word for it long enough to test it, but when he claims to know that it is so because of some theory, I might take his word for it long enough to test its properties, but would not know how to test the theory. After all, before Copernicus, Galileo, and Newton we did fairly well predicting the motions of the heavenly bodies by theories that were completely wrong. Now we find that Newton didn't have the whole story, but was good enough to get us to the Moon and back. Actually, I would know philosophically how to test the theory of a developer, but it's a lot more involved than anything I can do with my equipment. It's easier to be a chef who throws out the dishes that don't suit his taste than one who unerringly predicts how they will taste.

I have read that the first oxidation product of ascorbic acid is dehydroascorbic acid which is slightly more acidic and is not regenerated by any of our photographic chemical processes, even though the body knows how to do so. That doesn't give me a license to say what the effect on edge definition might be, but only that there might be an effect that might be different from that which a sulfite antioxidant might have.

Enough, already.

Alan Johnson · Sep 19, 2007

Suppose metol diffusing in from the bulk solution is not regenerated at the exposed emulsion but becomes exhausted.Then metol diffusing laterally from unexposed film would have a disproportinately large effect in developing the edges of exposed emulsion.
Suppose phenidone diffusing in from the bulk solution is regenerated at the exposed emulsion.In that case,phenidone diffusing laterally would have proportionately less effect in developing the edges of the exposed emulsion and the edge effects would be less.
This might distinguish eg FX-1 from a PC type,only testing would tell.

Photo Engineer · Sep 19, 2007

According to the way I read it, Metol(ox) can regenerat to Metol with sulfite, but HQ(ox) with sulifte gives HQ-Sulfonate, a less powerful developer. Phenidone(ox) can go 2 ways. It can react with ingredients in the developer to regenerate Phenidone or an inert substance thereby reducing the quantity of Phenidone present.

Again, this is too complex to answer. You can sit and theorize all day long, but in the end, you must mix the developer and thoroughly test it. After testing, you go back and design experiments to discover the methods by which each observation was produced.

Independantly of all of this, you can develop the math which describes how each type of effect will appear, but that is what Kriss did, and then he showed why you had to have certain effects which are a combination of edges vs contrast and etc...

The math proofs of Kriss are 60 pages long!

Just do the experiment and hope for the best.

PE

gainer · Sep 19, 2007

Except that we cannot prove the truth of a proposition, I agree, if that means anything. We must design our experiments to disprove a proposition, and if they fail at that, we can say we have not yet disproved the proposition. That's a bit far out for photography, and I have used developer formulas without knowing the theory on which they were based, and not really caring, as long as they worked. Like the chef.

My biggest gripe about the whole acutance, or should I say, the holy acutance grail, is that it amounts to looking for the wrong thing, unless it is to be used as an artistic effect, like a halo.

A process that produces just the right halo for, say, 8x10 film will not be suitable for the small formats, because the process does not know what size you're working on. Maybe the reason I'm happy with the least edge effect I can muster is because my 80 year old body will no longer allow me to tote the 4x5 or the 5x7. Sacro ileitis is a real pain in the ass.

Photo Engineer · Sep 19, 2007

Patrick;

I'll repost this here. It is a depiction of edge effects and how micro contrast goes up as the image size decreases. This is the ideal developer film combination in which smaller formats have higher micro contrast.

It is how a 35mm negative can have the same relative edges as a 4x5 image and the same relative appearance at an equivalent magnification and viewing distance.

The higher contrast with smaller objects in smaller frame sizes is magnified to give roughly equivalent image quality to the larger objects in a larger frame size. In effect, a telephone wire on a pole might be 10 microns in 35mm and 100 microns in 4x5.

This is a real example using a film / developer combination that was optimum for each other. It is also why we all seem to get different results with different film / developer combinations. These types of effects do not work together unless the optimum is used. Kodak works these out and makes suggestions for every film and developer to achieve this type of result.

These figures were taken from Kriss' article with his permission.

PE

gainer · Sep 20, 2007

I presume you are showing microdensitometer traces across silver images of lines of different widths. We are lacking information about the widths of the lines that were photographed. It seems that the narrowest line would look even narrower.

I still do not know why we should be searching for more and more pronounced edge defects. They will in any case be added to those that the eye of the beholder supplies.

Photo Engineer · Sep 20, 2007

Patrick, the line widths are as indicated on the traces. They were exposed at exactly that width. They are made to roughly simulate a given object at 35mm, 120 and 4x5 format sizes.

PE

Can You Make A High Acutance Developer Using Phenidone?

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