Boost film-speed with simple reversal process?

This sounds too good to be true. But the passage below is from Grant Haist's "Modern Photographic Processing", Vol II page 360-361. He is as reputable as they get. He describes a way to gain two stops of film-speed in B&W film by the following reversal monobath development:


Note that there is no fixer bath. This technique makes me ask several questions: If this does such a good job of boosting speed, why aren't people using it these days? What is the image-quality like? Will it work with t-grain films? If anyone has any experience or comments about this speed-up-by-reversal-monobath idea, I'd like to hear them.

Mark Overton

I can't answer your question Mark, but I will have to give this a crack tonight and see what I get.

Mark, I did a lot of workm on monobaths in the late 1970s there's something missing in this process.

A good vbasic monobath is Crawley's FX-6a

Crawley FX-6A Monobath

Sodium Sulphite (anhyd) 50.0 grams
Hydroquinone 12.9 grams
Phenidone 1.0 gram
Sodium Hydroxide 10.0 grams
Sodium Thiosulphate 90.0 grams
Water to 1 litre

Develop for 15-20 mins Monobaths in practice develop to completion of the fixing component after which no development can take place.

It's nomal to tweak a monobath by varying the Thiosulphate level from 70gm per litre to 125 gm per litre to suit the film.

Not so different, the fact that one's MQ and the other PQ has no real impact, Howell's monobath is more concentrated though hence the shorter development time. (Crawley's monobath uses normal Thiosulphate not anhyd)


Now the problem is that Howell's monobath will produce a negative image in 5 minutes, there's no reversal bleach, so even if the fixing component hasn't been completed before the reversal exposure to the photoflodd any positive image will be weak and alongside the existing negative image. So there's something missing here.

Ian

Ian Grant said:

Now the problem is that Howell's monobath will produce a negative image in 5 minutes, there's no reversal bleach, so even if the fixing component hasn't been completed before the reversal exposure to the photoflodd any positive image will be weak and alongside the existing negative image. So there's something missing here.
Ian

Click to expand...

Ian: Elsewhere (and sorry I didn't quote it), Haist explains the principle behind this. The thiosulfate is more active in areas of high development (ie, high exposure), and less active in areas of low exposure. So if the remaining silver halide is exposed after development, you get a positive image. The result is a weak negative image and a denser positive. Haist says that a process like this can produce high contrast images, with high minimum density due to the negative image. Note that some silver halide needs to remain, so the fixation in this monobath must be partial.

Mark Overton

That makes sense but then emulsions in 1954 were quite different to those we use today, they were thicker coatings and had a higher silver content.

My experience would suggest that the 5 minutes development time might well be too long for modern emulsions and the negative image too strong for subsequent reversal.

In addition the 4x the film speed is based on the old ASA/BS speed ratings before they were revised upwards in the early 1960's so in reality the claimed increase is just 2x or 1 stop.

Ian

I'm just starting to look into the idea of reversing B&W negative film (I want to project Adox CMS 20 and Neopan 1600) and reading through the instructions for reversing Tmax, it says you should expose at 50 instead of 100:

http://www.kodak.com/global/en/professional/support/techPubs/j87/j87.pdf

I've successfully used Crawley's MB to produce good quality negatives. Different films may need differing amounts of sodium thiosulfate in order to control excessive highlight density. I've used it with Lucky film, Efke 50, and good old Tri-X. I'm having trouble imagining how this will work, though. Maybe one day I'll give it a go.

The tone of that article makes it sound like supposition based on second-hand information.
In other words, the author never actually did the process but only read about it or spoke to somebody else who did. He's just reporting that information and adding his own commentary on top.

It's a lot like the way people who wrote opinions, back in the 1950's, and said things like, "In the year 2000, there will be a "flying car" in every garage."
There's no way to prove or disprove a prediction that can't come true for more than 50 years. Besides, who's going to be around to judge whether it is true? Still, people would read this kind of thing and take it as gospel.

I see a few red flags in the way that article that was written which tells me that the author is bullshitting his way through the subject.
I didn't say he always wrote bullshit. I'm just saying this particular article smells funny.

I have a long article in an old BJP Almanac on th e history etc of monobaths, one of the references is Grant Haist's 1966 "Monobath Manual". The important thing to remember is Haist is writing about someone elses claims, in this case probably published work by Hutson K. Howell rather than work HAist's done himself.

Having looked again at the formula and converted the Thiosulphate to the more usual Pentahydrated form which would be 84g/litre then it makes no sense as it's going to have stronger developing action than Crawleys FX-6a.

However it's likely this was a specialist monobath for a specialist application as Hutson K. Howell was manager of Itek's Photo Science and Photogrammetry. It's unlikely it was designed to give high quality reversal transparencies.

Ian

It's all supposing until given the old college try. I'm glad Andy C. is going to take a stab at it.

This certainly sounds like a bizarre process though.

I've been excited by a few processes that, when brought up to APUG, have been shot down for similar reasons; old films are different, it doesn't work, etc. Not saying that I don't believe these claims, but I guess we'll never really be convinced until we give them a shot for ourselves. For instance, I thought 'physical development' sounded like a panacea, but apparently it doesn't work(?).

Ok, but what I don't get is... if this is a monobath, the thio will be dissolving away the positive image while the negative one is developing. When the re-exposure comes, presumably the negative image will be done developing, and in turn the reciprocal silver-halide in those negatives areas will have been more thoroughly dissolved out (since "high dev = higher thio action") than say the silver-halide in wholly unexposed regions. But as the positive image develops, how can it ever exceed the density of the negative image? I guess the re-exposure is so intense that this is possible...

This sounds like photographic tight-rope walking!

While in college in the 60s part of our course work involved mixing chemistry and we tired several monbath developers, the idea was to have a very fast acting monbath that with a short wash and forced air dry could be ready for the "special editions" for newpapers in short order. I dont recall which monbaths we worked on, but all had high contrast and very grainey. I also used the old black and white ide film that Poloraid sold in the 80's which I think was a monbath. I liked the Polorid process.

holmburgers said:

It's all supposing until given the old college try. I'm glad Andy C. is going to take a stab at it.

Click to expand...

I'm not saying it won't work or, at least, didn't work for a particular application at a particular time. I am simply saying that the author seems to be reporting what others have told him without ever having done it himself.

It would be like me saying, "There's a guy who can develop Kodachrome in his home lab."
We all know it has been done. We know how it was done. There are a few who can even do it themselves but I've never done it myself.

The article is logically the same as me telling you how to develop Kodachrome in your home lab without ever having done it myself.

If I told you how it was done (and recounted the process correctly) would I be wrong in reporting that? No.
If I gave commentary and made suppositions on how one might do it in his own darkroom, would I be wrong? No, with caveats. That caveat would be that I didn't relate opinion as if it was fact.

The difference is that, at the time that article was written, one could give opinions and the reader would probably understand that. After all, he was an expert in the field. Other readers would likely understand that. However, in this day and age, we don't write with the same style and it's easy to misinterpret that style to mean that he is telling us facts.

Not saying the guy is wrong. Not saying the article is bad.
He is probably right. The article is probably very good for the time it was written.
I'm simply saying that we need to read critically and account for things like that.

Yes Randy, I'm sure you're right about this; I didn't mean to sound like I was countering what you said.

What I was hoping to say, ultimately, is that someone's gotta test it; we need to revisit it in present day and make our conclusions based off that, because like you say Haist probably didn't do it himself and is just kind of passing it on "for what it's worth".

The monobath formula itself isn't exceptional it's close enough to some of Haist's own and Crawley's FX-6a, it was published in 1954 and is MQ based, Phenidone was only just becoming commercially available, and Haist, Crawley & others used Phenidone in the late 50's/early 60's, PQ monobaths are less afffected by bromides than MQ.

It's going to develop faster than FX-6a and Haist's own quite similar monobaths, the rate of fixing is depenant on the percentage of Sodium Thiosulphate which is usually somewhere between 7-12%.

The question that needs to be asked is why is this Monobath being used to reversal process film, what was the application, we know now that Haist writes that there is a weaker negative imge alongside the strong positive image.

From a practical point of view it'd be useless for producing reversal B&W slides where you need clean highlights etc, but it may have been useful for an industrial/scientific applied use of photography to process a recording material.

I used similar monobaths with a film type orthochromatic emulsion and also normal photographic papers and the development is quite fast, you need the longer times recommended for FX-6a to ensure fixing is complete.

So the question to Mark is does Haist say what application Howell was using this monobath as a reversal developer with ?

Ian

I just tried it and this has to be the crappiest developer on record [do anything to get out of writing a final report].

Exposed Arista 100 EDU at 400, developed it as per instructions for 4 minutes.

The result is an underexposed, underdeveloped negative with blown highlights. Or, I suppose you could look at it as an overexposed, overdeveloped negative with no shadow detail - shadows starting at Zone IX or so.

Not even the faintest trace of any reversal of anything.

There may exist a film/developer-tweak/time&temperature combination that works, but the results I had are so far out of the ballpark that it is hard for me to imagine this ever going anywhere.

YMMV and all that.

In Haist's defense he did attribute it to a FOAF [to put it in modern English].

Sometims Monobaths were used for very strange applications, it would appear that Hutson K. Howell was a highly respected photo chemist.

Without knowing what the true application of this Reversal monobath was we could go round and round in circles.

Ian

Nicholas has beaten me to it by the looks of it. I waited until the sun came up this morning to shoot a bracketed roll which will be souped after I take the kids to swimming classes.

Not expecting anything spectacular, but glad I have waited to read Ian's suggestions.

Will try to post examples by the end of the day.

Thanks Nicholas for doing some real tests!

But the underlying question, "Can reversal processes improve film speed?," might not have been given a whole lot of thought back in the day when it was kind of hard to print from positives.

You have to nail the exposure, because instead of all that latitude now you are working with slides. But think of all the threads that teach us how to do that.

I used to shoot Panatomic-X at 80 for reversal and its rated speed is 32 for regular process.

There are situations when you might need a positive to print from; where any kind of excess fog or density (which would render a poor slide) could easily be printed through.

Just a thought..

Paul Gilman showed that ISO 400 emulsions could be boosted to ISO 25,000 by appropriate reversal processing using heat. Grant found the same thing with negative heat processes.

PE

Photo Engineer said:

Paul Gilman showed that ISO 400 emulsions could be boosted to ISO 25,000 by appropriate reversal processing using heat. Grant found the same thing with negative heat processes.

PE

Click to expand...

Wow, I thought that kind of speed boost required liquid nitrogen... like astrophotography work...

Reading Grant Haist's paragraphs again, he does not state the purpose of these reversal monobaths. He does state that "after light flashing and development, the final image consists of a contrasty positive image and a low-contrast negative image. The contrast of the positive is so high that for most purposes it is unnecessary to remove the negative silver."

With modern films, I suspect we would need to experiment with the amount of thiosulfate. Too much, and you get an ordinary negative because too much halide was removed. Too little, and you get near-solid black. Also, I'd probably start with normal exposure, as boosting speed would probably make the whole process more unstable. Finally, development time will matter. Too long, and you get an ordinary negative. Too little, and you get black. Did somebody mention a tightrope?

PE: Do you know why heat-reversal or heat-development boosts speed so much? 400 to 25000 is an enormous speed-up. Do you think this reversal monobath would (1) work at all, and (2) boost speed?

Mark Overton

I have too have had no success with this. Have run Foma 400 and ORWO UN54 both were bracketed -2, -1, 0, +1, +2. Processed at 22degC for 90sec, then increased development time by 30sec for each subsequent test strip of film until I got to 6mins. I got results similar to Nicholas - all frames looked underexposed/under developed no matter what the development time was. Does Metol or hydroquinone go off even when stored with silica gel to keep out moisture? What puzzled me was I cannot even see the effects of the bracketing.

To be sure I had not stuffed up exposing the film in camera I developed in HC110 for 7mins at 20degC and all fine.

Other point was try as I might, I could not get a hint of reversal/fogging. Not even going to try to post sample images.

Well I had a good day playing in the darkroom.

More cogitations as a result of my one unsuccessful experiment:

As Mark Overton stated, the formula may have much too much thiosulfate. The formula given in Haist specifies 3-5 minutes for devloping time; my finding is that 4 minutes developing time is too long for ordinary B&W films and results in a negative image.

Rating at 1/2 to 1/4 box speed may be a more appropriate starting point for bracketing.

This technique will not produce pictoral results. I think the best one can hope for is a very high contrast positive with lots of fog. Haist even gives formula for using a bleach to get rid of the fog.

I fear reversal monobaths may be a candidate for the first serious submission to the Journal of Irreproducible Results.

This isn't a special developer, it looks just like regular reversal just about.

If you're not getting results, b&w bleach, wash, re-expose and develop and fix etc.

Assuming your fixing in first bath is roughly more or less balanced.

A weaker/underexposed image will give you a denser slide. Perhaps the right amount of fixing may balance that to a normal density range (as a positive), rather than overly dense.

Photo Engineer said:

Paul Gilman showed that ISO 400 emulsions could be boosted to ISO 25,000 by appropriate reversal processing using heat. Grant found the same thing with negative heat processes.

PE

Click to expand...

Is the description of the process in a book or online or somewhere available to read?