Fogging during stop wash

[narigas2006]

Dear All,

when I am developing paper (ilford rc, or whatever), I can see the paper fogs if I wash between the developer and fixer (but no fogging is seen if I go straight to the fixer). Any water drop in fact fogs the white borders of the paper. I was suspecting that it could be the pH of my region. Does it make sense? Cheers

richardson

 

[Svenedin]

What are you using as your stop bath?

 

[narigas2006]

just washing in water.

 

[Svenedin]

I'd suggest using an acidic stop bath. You can buy stop bath (either acetic acid or citric acid with or without an indicator to tell you when it's exhausted). You dilute the concentrate in water. Or you can use distilled vinegar from the supermarket ("white vinegar") watered down.

 

[bdial]

You should also do a safelight test. Is the paper old?

 

[narigas2006]

thanks and thanks! yes, the paper is old, very old, but its strange that it does not fog during development. It develops very nice. Just when I put it in the tap water

 

[MattKing]

thanks and thanks! yes, the paper is old, very old, but its strange that it does not fog during development. It develops very nice. Just when I put it in the tap water

The tap water just dilutes the developer on the surface of the paper, while leaving the developer that is soaked into the gelatin, which subsequently has to diffuse out of that gelatin.
As it is old paper, who knows how much that affects diffusion rates.
If your fixer is acidic, it will be much more effective than tap water at stopping development. Unfortunately, that will also markedly reduce the longevity of the fixer.
Even if stop bath isn't your friend, it is the fixer's friend.

 

[Doremus Scudder]

I don't understand why a print should "fog" in the stop bath... You are doing everything under safelight, aren't you? Don't turn on the white light till at least halfway through the fix step. And, what are you using for stop bath? Any commercial acid stop should not fog paper. Fogging happens when unfixed paper is exposed to light, with or without carried-over developer. Developer in the mix makes the fogging faster. Something is not quite right here...

Best,

Doremus

 

[glbeas]

Any sulfur smell to the water? I had a friend once whose well water came from a pyrite bearing strata, smelled bad but kept the mosquitos away quite well! Any sulfide content would do that though I would wonder how well the sulfites in the developer are neutralizing that. I wonder how a high iron content would react as well.

 

[pentaxuser]

To add to Doremus' point. I have used old age-fogged paper under safe safelight conditions and while the development was taking place under safelight conditions it was not all all obvious that the paper was fogged. Not until I was more than half way through the fixer stage and had turned on the room-light, safely, was it clear that the paper was age-fogged.

A water wash may not stop development instantly so the paper continues to develop for a while in the water but water cannot fog paper, nor unfortunately can an acid stop bath prevent age-fogging either.

If you cannot be sure your safelight is safe then here's what to try. In total darkness, expose normally(i.e. under an enlarger light) then simply fix the piece of paper then put the light on to get your bearings if you need to. Leave paper to one side. Then again in total darkness expose under enlarger, develop, water wash and fix another piece of paper. Turn on the room-light and compare. The only fixed piece should be white and the developed, water stopped and fixed piece will be a shade of grey in the border area if there is age-fogging. If there is no signs of fogging then your safelight that you haven't used for this experiment but had used when processing, isn't safe. If there is greyness then this is age-fogging and how grey will depend on the extent of the age-fogging. Badly age-fogged paper will be quite grey and may lack contrast as well, making the print look flat and a bit insipid.

If the borders are only a very light grey and you appear to have good blacks and white, with a range of correct greys in the print such that contrast is still reasonable then get some benzotriazole and add to the developer. This is a rescue plan only and the print compared to fresh paper may not be as good but might be good enough.

pentaxuser

 

[RauschenOderKorn]

I assume you are using an acid fixer which will also work as an effiicient stop bath.
The water will only wash away the developer, and that occurs quite slowly. So if you have a safelight or fogged paper problem, the development will continue much longer through your "stop"-wash until you put the print in the acid fixer.

A proper acid stop bath (I am using 2% citric acid, but any other product will do, too) should fix your problem.

 

[Sirius Glass]

just washing in water.

And there is your problem. Either leave the lights off until the print is in fixer for a short period of time or use real stop bath, not water.

 

[pentaxuser]

And there is your problem. Either leave the lights off until the print is in fixer for a short period of time or use real stop bath, not water.

The way I interpret your comment is that once a print is in a real( acid?) stop-bath you are safe turning on the light and you do not have to wait until the fixer takes effect, is this the case or have I misunderstood what you are saying? Thanks

pentaxuser

 

[MattKing]

The way I interpret your comment is that once a print is in a real( acid?) stop-bath you are safe turning on the light and you do not have to wait until the fixer takes effect, is this the case or have I misunderstood what you are saying? Thanks

pentaxuser

One will only see fogging/additional development if the exposed but not yet fixed out silver halides come in contact with a reducing agent (developer).
So if the acidic stop bath neutralizes any remaining trace of developer on the print, there should be no further development in the print, and whether or not the silver halides in the printing paper are exposed to light, they should still be removed by the fixer without affecting the image.
If you have ever investigated Phil Davis' Beyond the Zone System, you may recall that he advocates turning on the light when the film is in the stop bath.

 

[Arklatexian]

Suppose your "tap" water is alkaline. So is most developer. Many municipal water sources are either alkaline or acidic and this can affect both developing film and paper. Neutral Ph is 7 so check with your municipal water supplier and ask what your water Ph is. Much over or under 7 can definitely affect your results. Acidic stop removes all doubt and gets the film or paper ready for the fix. I usually fix for ten minutes and don't turn the lights on until after five minutes. Yes, I am old fashioned, why I even wash for an hour. after fixing, haven't had a print fade yet except when I screwed up. If you are in a big hurry, I would suggest staying out of a darkroom............Regards!

 

[Arklatexian]

One will only see fogging/additional development if the exposed but not yet fixed out silver halides come in contact with a reducing agent (developer).
So if the acidic stop bath neutralizes any remaining trace of developer on the print, there should be no further development in the print, and whether or not the silver halides in the printing paper are exposed to light, they should still be removed by the fixer without affecting the image.
If you have ever investigated Phil Davis' Beyond the Zone System, you may recall that he advocates turning on the light when the film is in the stop bath.

Does Phil Davis give a reason for turning on the light when the film is in the stop bath. Is there an advantage? I think not........Regards!

 

[MattKing]

Does Phil Davis give a reason for turning on the light when the film is in the stop bath. Is there an advantage? I think not........Regards!

IIRC the BTZS tubes he designed didn't have a light trap. Turning on the light meant that you could see what you were doing when you poured out the stop and poured in the fixer.

 

[RalphLambrecht]

Dear All,

when I am developing paper (ilford rc, or whatever), I can see the paper fogs if I wash between the developer and fixer (but no fogging is seen if I go straight to the fixer). Any water drop in fact fogs the white borders of the paper. I was suspecting that it could be the pH of my region. Does it make sense? Cheers

richardson

there must be white light getting to the paper during the wash!

 

[pentaxuser]

If you have ever investigated Phil Davis' Beyond the Zone System, you may recall that he advocates turning on the light when the film is in the stop bath.

Thanks Matt. I haven't read the BTZS book but useful to know that once in acid stop, everything stops so to speak and it is then safe to turn on the room-light.
Not part of this thread really and I hope this doesn't constitute a "highjack" but extending what you said in your reply, can I assume that the same reasoning applies to film development as well i.e. once acid-stopped it would be safe if exposed to white light before fixer? If this is the case then you may guess what I am going to ask now. Namely is there a way from this to do a form of development by inspection as in stop, examine, then fix if OK and if not remove acid by some means( water dumps?, alkali solution?) then replace with fresh developer or has the stop permanently changed the film such that there is no going back with further developer? I strongly suspect the latter otherwise it is likely that if this was a viable method of development by inspection this would have received a lot more publicity.

Thanks

pentaxuser

 

[RauschenOderKorn]

An acid stop is not permanent, it can be washed away. But exposing the film/paper to light after the stop before the additional development will fog it.

 

[Saganich]

Is it fog or staining? Same water for mixing developer and fix? The way this is presented the water (even as a drop) discolors paper but not fix. The fix then is neutralizing the effect? You'll have to try fresh paper to start with. I agree with Ralph, look closely for local white light leak or reflection.

 

[lantau]

When you look at various process documentation, like the ECN2 cinefilm process, you'll see that they say room light is OK after the stop.

Obviously there will be latent fogging, which means you cannot restart development. And thinking about it I'd expect printing out to occur if you left the material out for extended periods of time before fixing. With photo paper I see that it 'fogs' within minutes when taking a sheet of of the package and switch on the light. I didn't check if the fix will eat that up, though.

 

[Svenedin]

When you look at various process documentation, like the ECN2 cinefilm process, you'll see that they say room light is OK after the stop.

Obviously there will be latent fogging, which means you cannot restart development. And thinking about it I'd expect printing out to occur if you left the material out for extended periods of time before fixing. With photo paper I see that it 'fogs' within minutes when taking a sheet of of the package and switch on the light. I didn't check if the fix will eat that up, though.

Actually I tried this recently. I had messed up an exposure on a sheet of Ilford MGIV. It wasn't worth developing so I put the paper on the table and then turned the lights on. At some point a pair of scissors was accidentally placed on the paper and there was quite a nice ghostly image when I moved the scissors. I put the paper straight in fix and the image disappeared leaving paper that didn't look like it had ever been exposed at all.

 

[pentaxuser]

. I put the paper straight in fix and the image disappeared leaving paper that didn't look like it had ever been exposed at all.

Pity this doesn't work with film If I have understood lantau's comment properly and that's not certain, it would appear that the film is fine in roomlight and won't change but if it isn't how you want it, then any redevelopment results in latent fogging appearing in the film post further development thus preventing adjustment by further development post inspection.

If there is a relatively non technical explanation of this I'd appreciate it.

pentaxuser

 

[Svenedin]

Pity this doesn't work with film If I have understood lantau's comment properly and that's not certain, it would appear that the film is fine in roomlight and won't change but if it isn't how you want it, then any redevelopment results in latent fogging appearing in the film post further development thus preventing adjustment by further development post inspection.

If there is a relatively non technical explanation of this I'd appreciate it.

pentaxuser

It does work with film. If you expose film to light but don't develop it first and put it straight in fix then the result is clear film. Nothing. The only rule in photography. Don't fix film first!!