B&W Reversal Processing Controls

[vencahaus]

thank you, I knew about this book, but have no chance to get it in my hands

1. i'm surprised he recommend one universal concentration of potassium thiocyante ... I'd tune it for each film separately, low speed films need usually more

2. what does it mean " avoid white light " in clearing bath?

 

[johnielvis]

the silver solvant, as far as I can see, is only to add speed to the process---all of the reversal processes in that book were optimized formotion picture processing---MILES of film=develop it FAST....

d-19 straight as I outlined above will do good for tmy400 at ei50 and also for hp5 @ ei400

you can do the SAME THING that the the silver solvant in the 1st dev does and BETTER by POST BLEACHING---this does the highlight clearing AND it's controlled--you do it by inspection--as many treatments as you want till it's right---and no mussing around with the developer properties

 

[holmburgers]

#2... I dont' know, that's what Wall & Jordan's book says. Basically just don't expose the film during the clearingtime. But it seems like a useless suggestion, right?

#1... You could be entirely right. I guess a could place to start would be between 2 & 5 g/L, encompassing both author's suggestions.

I looked into D-19 a bit (new to me), and it's a high-contrast, high-grain, scientific type developer. It has high capacity and relatively good shelf-life. It makes sense that this would be a 1st developer, since it's creating a pretty hard negative image, thus the positive should be nice and punchy, with low grain.

I can take another look this evening and try to clarify some of these recommendations.

edit: The impression I get about the silver solvent is not that its only purpose is speed of processing, however that is a concern for movie film as noted by Haist. The real reason is for physical development. Here, check out this (there was a url link here which no longer exists) Not to mention, the solvent acts differentially, and complentary within the image, that is, it works where it needs to and not where it doesn't. I'm afraid that a farmer's-type reducer would decrease overall density, as opposed to preferentially in the highlights. That seems like a lot more fuss to me. Additionally, it isn't mentioned in either text, though that's not to de-validate it by any means. I am just curious where you learned or discovered it.

 

[johnielvis]

I've done it--post bleaching--quite a lot of it--there's usually some extra dmax that you can strip away and it will not make a difference at all--and the very dilute farmer's reducer DOES preferrentially take away from the highlights only--try and you will see

you may want to do str8 d-19 vs d-19 with hypo or cyanate in it to compare---I also considered doing phyysical development with silver intensifier as an AFTER treatmetn AFTER bleaching--I haven't gotten around to that yet, but it looks promising--particularly for pushing film---I mean--you can't get better than being able to basically develop by roomlight inspection via bleaching/intensifying, can you? perfectly tailored development each time--that's what I'm shooting for eventually....

OH--where did I learn about it? nowhere--just thought it all up on my own---OH----a while AFTER I started doing the post-bleaching, I learned that Steiglitz used to do his lantern slides that way---it was from some artsy article on steiglitz's lantern slides---Apparently Steiglitz would use post bleaching as a PART of his process---he went from second developer to hypo...THEN...straight to STRAIGHT ferricyanide--very dilute---for the bleaching---since the hypo was still impregnated in the emjulsion---he got the best dramatic scenes of snow that way----and he'd also bleach locally afterwards for effect-re-touching for artistic intent

 

[holmburgers]

OK, I can definitely see the appeal in that.

I think I will have to go consult some older texts on screen-plates, because I know that they did all sorts of intensifying treatments, and what not.

I understand how the approaches would be completely different if working with a single image as compared to a thousand feet of motion picture footage.

Makes you wonder what dr5 does, doesn't it?!

 

[johnielvis]

well....after my intial failures using the kodak kit....then I was about to give up thinking that the books were right about modern emulsions being not suitable...then I saw that mr dr5 was doing it, so i decided to keep trying and now I can control things pretty good and am getting better and better results---the more things I try the more tools I have available

 

[dr5chrome]

..there is useful info in this book regarding this subject, but personally I find many of the conclusions flawed. I had not picked up this book, almost 9yrs after the creation of dr5.

btw, useful dmax stats @ 3.00. only in some cases can a low dmax film be useful, and that depends on the film.

dw

Wondering if anyone found this summary useful, and if so, what might you be doing differently in your next process?

I'm gonna switch to one of the thiocyanates for silver solvent, and obvserve some of the more esoteric rules listed, particularly the emphasis on 1st rinse.

Also, are there any other developers that come to mind that fit the above requirements? I could post a more comprehensive set of requirements for the developer if anyone is interested, or I could post the 2-part as well.

I find it interesting that D-19 is so highly recommended, Ilford's "equivalent" being Phenisol, and yet in Ilford's RP pdf they don't recommend it. Additionally, they recommend hypo, by all accounts an inferior solvent. But perhaps they are trying to make it as easy as possible, without the need to buy more obscure things.

 

[holmburgers]

..there is useful info in this book regarding this subject, but personally I find many of the conclusions flawed.

Which conclusions might you be referring to? I won't tell anyone...

 

[willrea]

Alkaline thiourea accomplishes the same thing as sodium sulfide, but with almost none of the smell.

It's more of a chocolate toned slide than sepia if you ask me.

 

[holmburgers]

Something I'm curious about is the extent to which a reversal processed film can be pushed. For instance, if you can get 1600 out of HP5, is it possible to get even remotely close to that speed by RP??

 

[johnielvis]

pushing pulling changes dmax if you compensate with development---however--I'm now experimenting with a chromium intensifier---just got the fixins for it.....so, now I'm in a position to develop to get the highlights where I want them or shoot at the speed I want AND be able to darken things back the way they should be

I've already had nice success with shooting at higher speeds--but using the SAME deveopment (not increassing it) as for normal--this gets you dark transparencies..but then ferricyanide bleach pulls out the highlights nicely---if you push too much, then the bleach takes away dmax....intensifier should rectif y that....next is experiment--then bamek anice table of times....it's my opinion that each film/developer combindation has a SINGLE development that will result in max blacks..after that you lose dmax..any less deveopment and you end up with things being darker than they otherwise can be...so I'll come out of this thing with a list of film, deveoper times/temps for THAT FILM, and a list of speeds and the required post processing for that speed--so many minutes ferricyanide...so many minutes intensifier...etc...what I've found that works ...or at least a ranking of the times from best blacks to worst blacks...from darkest to nicest hightlights....I'll have to think it up...FIRST have to DO it though.

 

[holmburgers]

Thanks John, I'm excited to hear how your intensifier works out. If one could get a transparency that looks as good as a print from 1600 pushed film... we'll be in business.

So, I guess the problem with increasing 1st development is that you start developing lots of silver and this gets bleached, resulting in a very thin poz. 2 thoughts; adding a restrainer and/or reducing solvent concentration. I know nothing about restrainers, but wouldn't/couldn't reducing fog help out with the low dmax?

Although I respect your pursuits with intensification & reduction, at the moment I'm wanting to keep it simple and see how much I can get with the basic processing steps.

 

[johnielvis]

I know--mee too--wanted to make it simple...if that's the case, then you'll have to just shoot at the lower speeds so that your exposing at the portion of the film curve that you want--it's purely physical brute force then--jsut find the dev times (longest possible) that give the lightest blacks you can toleragte--then find the right exposure for that and that's optimum for no other processing---restrainer don't help--you want to find the developer that gives max dmax period (after bleach/re-deveop, that is)...restrainer will only lower your contrast==this means DARKER---you want as MUCH contrast as possible--to break into that top of the film curve to make sure it all gets bleached out. SO---max blacks is judgeemetn---do a 1st deveopment time test...till it gets unacceptabley low dmax..this is your max dev point...then find your speed from exposure and always deveop there---THEN..try differ ent deveopers and repeat--some deveoper s work better with different films...in general, you want hight contrast as possible.

 

[Mike Wilde]

I have not done a ton of reversal processing, but what I have done I find is most easily controlled by shooting a step wedge, and plotting the denisty of the steps after processing . Take careful notes, and repeat, carefully trying to only vary one variable at a time.

Yes, thoicyanate and time/temp in first developer is most important. Exposure is also important. The second developer is usually done to completion, unless it gives you too high a Dmax, which is typically not a problem if you are trying to get a high EI for the exposure. I do multiple identical serquences when doing the first run of test exposures, and snip notches in them as being exposed (35mm camera back on polariod copy camera). Then when processing I will pull off the first five of so step wedges up to the first notch after first development and stop/rinse. I toss them into the fix to see what I get before reversal. Then the rest of the film goes in to the rest of the reversal process. Just first developer run will show you the best speed you will get with the first developer. The number of steps and thier density will tell you waht you are proceeding with to go on with on the subsequent steps.

 

[holmburgers]

Mike, I am fond of your methodology, particularly only changing one variable at a time.

Now, I have a question for you sensitometrists out there.

Let's assume the desired d-max in a positive is ≈2.4 (>2, as high as 3 according to dw). Now, I don't know if anyone has been following my 'autochrome' thread, but basically I'm using a sheet of 4x5" slide film with a close-up picture of a television screen on it and placing this in contact with b&w film to produce a primitive color photograph.

Long story short, the screen takes away 2 stops of light and will be in front of the b&w positive for viewing. Sooo, that means my d-max in the silver positive can be the equivelant of 2-stops lighter and still be perceived to have good density.

If using a dmax of 2.4 as our baseline, a 2-stop filter + a density of 1.8 would appear just as dark, would it not? 0.3 = a doubling or halving, right? (I'm new to logs)

 

[Mike Wilde]

To get the hand of logs, look to DIN film speeds. They are like logs x10. EI 100 is DIN21, EI 200, twice as sensitive as EI100 is DIN 24.

Your math on the density of the transparency plus screen makes sense. I would recommend that you see what lets you vary the dMax, in case the sceen is not quite 2 full stops in all colours of original scene lighting.

 

[holmburgers]

Thanks Mike,

If anything, perhaps it tells me that having a lower-than-is-generally-considered-satisfactory density will be ok in my case.