Foma papers have incorporated developers.
Originally Posted by Ian Grant
I will also try a normally exposed print, to see if this is fog or development. I hadn't read any of these threads before and was very surprised when the water+soda had such a strong effect. ( I was hoping to soak a pure white sheet in it, and then slowly add in coffee until I saw some development.... the soda+water all by itself went much further and much much faster than I wanted. )
A simple test will prove + or -
First, I should have said thank you for that response. I'm not a chemist so I had no idea at all, but that answer was not "futility", so I was encouraged to explore further. After tonight's work, I am greatly encouraged and think this might work, but still need to do a lot more testing.
Originally Posted by Photo Engineer
You are absolutely correct: a simple test was all that was needed. The answer is "yes", and that fixing is a further consideration. By reducing the concentration of sodium carbonate, or adding sodium bicarbonate, the effect is reduced and it happens in a very systematic and controllable way.
I started a little further back in my tests tonight, just to be sure:
1) No effect whatsoever in plain water. ( had to check )
2) No effect in water with increasing amounts of sodium bicarbonate.
2a) Left to explore further and very intriguing: test strips that went into the bicarbonate solution would not develop later even in strong sodium carbonate solution. It has "disabled" the active agent.
3) Dark grey as observed yesterday with 1/4 t "washing soda" per 2oz water. Several tests confirmed that the tone changes with concentration of sodium carbonate. I don't know enough about this but I think the ph will max out as the solution gets saturated, but I don't know where that point would be, and for what I'm doing it doesn't matter: I'm trying to reduce the effect. ( I'm not assuming this is ph, but it is related to concentration. )
4) Lighter grey after adding 1/4 t bicarbonate
5, 6, 7...) each addition of 1/4 t made the grey lighter, by an amount that was very noticeable and looks a lot like a step card.. it is easy to judge. I did not time the reaction carefully, but my impression was that it did not take longer. All of these tests ended after about 15 or 20 seconds with no further "development". Presumably the agent was exhausted.
Now things get a little interesting when I tried fixing the test strips ( after wash )
I got various shades of tan and brown in the "lighter versions". Most of the grey bleaches right away in the fixer ( doe this mean that it is not reduced silver? ) The darkest ones still retained some grey ( so I think that means there really is silver and this isn't all about dyes or staining. ) The very darkest ones look like a flat somewhat underexposed print. The darker ones have an unpleasant drab greenish tinge to them.
These were strips from a lumen print and some of the intermediate ones fixed to a light chocolate color with hints of pink in the highlights. Some have hints of yellow in the light brown.
Now very interesting:
In the same intermediate ones, contrast increased dramatically in fixing and especially during dry-down. I could actually see details emerge and subtle color shifts as it dried. I have the impression that there is a "sweet spot" that will maximize contrast and have nice colors. I have one snippet that I think might contain *more* detail than the original lumen print ( but the contrast is low. )
The fixed images from two hours ago have been sitting directly under a fluorescent lamp since and have not changed. I think the images are fixed but I need to test that idea by leaving them out longer.
I've got quite a lot more I want to test but this is pretty fun.
If you have a Carbonate solution, it will have a given pH based on the amount of Carbonate. As you add Bicarb, the pH becomes more acidic and the activity of any incorporated developer goes down.
Of course, the amount of solution and agitation also allow the developing agent, if any, to decrease.
In some cases, the developing agent is blocked to prevent spoilage. Base activates it, and less base means less activity due to less unblocking.
These are guesses, not having run the tests myself, but they are based on sound chemistry.
As for the changes on fixing, well, in many cases that depends on how finely divided the silver is and how acidic the fixer is. In this case, I would suggest a neutral or basic fix that is rather dilute. IDK. Just keep us posted.
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Not the ones I've used but then I don't use RC papers and it's these that might.
Originally Posted by Alessandro Serrao
Very quick update. After confirming that what I was observing was development and not just fogging, I also confirmed that "regular" caffenol ( coffee + sodium carbonate ) used after initial development with just sodium carbonate and incorporated chemicals completed, does continue development further and does reach black.
Development with "normal caffenol" for MGIV consists of two things: the development induced by the alkaline solution and incorporated chemicals which happens very quickly, followed by slower development by the caffenol itself. The first part is strongly modulated by the pH.
My next steps will be to make "standard photograms" and then systematically vary temperature and pH. Probably next weekend!
Edit: I'm also planning to follow up on PE's suggestion of a neutral or basic fixer, well diluted. Need to make an order for that.
Last edited by NedL; 01-21-2013 at 03:22 PM. Click to view previous post history.
Reason: forgot to mention
Paper made by traditional methods needs to be aged before sale. Addition of developer means this step can be skipped thus lowering costs. the downside is the shelf life of the paper is considerably shortened.
The Ilford rep told me this decades ago, when they had reps, but Ilford is playing the deny game now.
This is very new to me! We coated and sold paper as fast as we could coat it. There was no keeping needed. That is, since the new hardeners came into use in the 60s. Incorporated developers had nothing to do with any Kodak keeping situation.
Do you know what qualified the Ilford rep to state this? How close to the "people in the know" at Mobberley was he/she? If it was decades ago maybe it was even pre-Mobberley. How long ago was it? Might it be that long ago that what he/she had to say bears no relation to Harman's manufacturing method today?
Originally Posted by Ronald Moravec
Any idea why paper needs to be aged before sale or was this some thing that the rep said and it sounded correct?
Did you notice any reduction in shelf life in your own case after the alleged addition of developer?
I'd like to get the bottom of what sounds like an intriguing explanation of an alleged change