What is the necessity using Chemical Stop Baths?

[mtbbrian]

Ah ha! So you where talking about me. I wasn't sure.

So now you catch up with things!

Brian

[photophorous]

I don't know if fade is the correct term, I think it will show signs of discoloration, assuming it survives being exposed to light that long.
But you MIGHT, be able to fix and wash it again and it SHOULD be OK.
It's been a while since I have developed any film so I don't completely remember.
Brian

If it's not fixed properly, it will be cloudy. In this case, you can refix it later. I don't know how much later you can go, but I've heard of people refixing after weeks or a month. Assuming it was in the fixer for at least a minute or two, exposure to light shouldn't be a problem...unless you try to develop it again.

The problem The Wombat was describing sounds more like incomplete washing. Fixer is acidic and if it's not properly washed out it will slowly cause the plastic film base to deteriorate and become discolored, which can not be reversed.

[Jason Hopkins]

Immediately after draining the developer, I fill the tank with water and agitate for 30 seconds, about 1 inversion per second, then drain it. Then I do it again, but I'm not as careful to go for a full 30 seconds the second time.

Here's my logic (which could very well be wrong): As soon as you pour in the stop water, any developer that is on the outside of the film will be washed off and diluted to a point where it would take hours to actually effect the development. There is still developer that was absorbed into the emulsion, which will not wash off as easily. The time I spend agitating will remove most of it, but after 30 seconds or so, it's pointless, because that tiny amount of developer remaining inside the film emulsion will have exhausted itself by the time I'm through shaking the tank. So, I suspect a small amount of developing continues in the initial 30 second "stop" wash, but as long as I'm consistent with this process, it is factored in. I've never noticed any visible defects on my negatives, and I've never had a problem with premature death of my fixer. I hope there are no problems that I'm just overlooking.

Paul

Paul thats a very interesting and well thought out process. I am inclined to try this with the new developer I have coming in (DiXactol) as its a dye based developer. As previously mentioned I would be a little leary of not using a chemical stop bath with a vigirous developer like d-76 or ID-11. Not to say it wouldnt work just fine...it just gives me pause.

[photophorous]

So now you catch up with things!

Brian

Yeah, yeah...I know.

[SmartWombat]

I'll start a new thread on this.
Because I want to try to recover them.

[Asylum Steve]

Using a chemical stop bath for film is a bit of overkill. Water works fine. A chemical stop is better suited for print processing, especially when you're in for a long darkroom session and/or re-use your fix. It prolongs the life of the fix...

To each his own, but using an indicator stop bath for tank processing kind of defeats the purpose. You can't see the chemistry to note a color change, and even if you could, you really should be working with fresh chemicals each time you process film.

Again, it's much better suited to a long print session where you can note the color change.

Boy, I can see I'll probably be spending a lot of time here to set you guys straight on all this stuff...

[drg]

LF b/w films benefit from a stop bath to control contrast and negative density. The largest I shoot now is 4x5 and only a few dozen sheets a year. Water in sufficient enough quantity will 'stop' the development but over that large an area it can sometimes cause a difference in negative density from one side of the image to another.

You may not need to do more than a dip and dunk and then move to a flowing water tray before fixing. Lots of water is good, filtered or deionised or distilled or some such type depending upon you source. In this way sheet film is very similar to prints.

A key to doing color sheet film either positive or negative is temperature control and that is one place where distilled and deionized (most deionizer systems also distill unless they are an inferior filtration/osmotic unit) H20 works better. Water that is anionic/cationic -ly neutral maintains temperature better.

Asylum Steve mentioned fresh chemicals!! Yes, mix only what you need for a particular session if at all possible. If you trying to keep the cost down, one of the large charts for developing times gives numbers for dilute solutions and longer times. This will also provide much better control of the resulting negative.

One advantage to steel tanks is having several and, working in darkness of course, you can pull the spool and move it to another tank for each step that is prefilled with stop bath/water/fixer/water after the initial developer.

A tip/trick: If you have been working in very dirty conditions, use a steel tank and distilled water and rinse the film before developing. Yes, wet film! Dirt and dust can actually get stuck on the surface of your film and it will make on occasion make a 'murky' area. It will change your development times, so experiment and make notes based on you developer's molarity, temperature and agitation methods.

If you want to invest there are clean air systems that blow a flat stream of filtered air over film prior to developing but they can and do cause static without humidity control and then you are right back where you started with dust.

I've mixed some notes between b/w and color processes, but I believe they are clear. If not I won't be insulted if you ask or point out something I've twisted to and fro.

[Asylum Steve]

LF b/w films benefit from a stop bath to control contrast and negative density...

Good points. I should have mentioned my work was all b&w 35mm and 120 film. LF and color materials could well benefit from slightly different procedures.

I should also add that I always used a pre-soak of distilled water the same temperature as the developer. A good habit for anyone to get into. Even in normal conditions, developer coats the film more evenly when it's damp and softened a bit than completely dry...

[Xia_Ke]

From my limited experience, I don't see why reusing chemicals is such a bad thing provided that you keep an eye on them. I only reuse my stop bath and fixer. Developer, Hypo, and PhotoFlo are single use only. I test my fixer for exhaustion every other roll. When I mix a fresh batch, I stick in a cut piece of film and time it until it clears, usually about 1 minute. During developing, I do double what the test time was. When my test time reaches the 2 minute mark, I mix up a fresh batch of fixer and also mix up fresh stop bath. I suppose I could go even longer with my stop bath as I've never even gotten to the point the Indicator changes color.

[Greg McCary]

I use stop bath too. I have heard you could just wash it out. But it is probaly the cheapest part of the process so I really don't see a reason to stop unless I am just out of stop bath. But maybe I should rethink it and just use water???????
Thanks for pointing all of this out. At least I know for sure I can just use water.

[Asylum Steve]

Thanks for pointing all of this out. At least I know for sure I can just use water...

Again, it depends on the way you process. When I souped my own bw film, I almost always pulled it, meaning I overexposed the shot (exposing for shadow detail) and underdeveloped it to keep the highlights from blowing out.

I used a very simplified zone system method, and in keeping with that, used a high-dilution developer at a relatively cool temp for a long developing time (again, this helps keep a wide dynamic range with lower contrast).

My point is water was fine as a stop, as the develpoment was slow.

Now, if I was using a high concentrate developer at a higher temp and short develop time, it would be much more important to halt that developing action more quickly. In that case, yes, I probably would use a chemical stop...

[reverberation]

I always have used stopbath...somewhere in the process. I think it is important. My experience with large ortho negs from a graphic arts camera have instilled in me the need to ensure my chemicals are fresh and each process is insulated from the next. These are essentially line art, areas of clear film and black. I have had some of my exposures show areas of gray after developing because I did not mix new chemicals.

With 35mm negs I will be careful, unless its tri-x or plus-x, for some reason I will try anything with these films. I think because I bulk loaded them for most of my formative years, photographically speaking. I think Steve makes a good point, expose for the shadows and develop for the highlights. DRG also has a good point with the distilled/processed water. If you want to burn copper plates its the only way to go.

[MiraxGrp]

Sorry i'm newbie , plz help to create new topic