Stop and fixing in daylight?

[Davesw]

I just watched the youtube clip on using the BTZS 4x5 deveoping tubes, and in this video the cap is removed from the tube after the developer and put in to a stop bath in the tube in room light,then the film is removed from the tube and tray fixed in room light! I was trained not to expose the film to light untill after fixing. any thoughts on this ?

 

[Michel Hardy-Vallée]

It was probably for the sake of demonstration only.

You don't want to expose your film to light before the stop bath! When the film is soaked with developer, it's at its most sensitive to light. One light leak, and your photos are done for.

When I print B&W, I sometimes turn on the light AFTER my print is in the stop bath, especially when it's unimportant stuff I need to see quickly. Under any light, an unfixed print will eventually print-out and darken, but under tungsten it's pretty slow, so you may have a window of a few minutes.

At any rate, this is not a shortcut you want to take when you're printing fine stuff.

 

[Photo Engineer]

I would not turn on the lights until the film was in the fixer for about 1 minute. I would leave the lights off longer if the fix was alkaline and I had not used a stop.

PE

 

[bobwysiwyg]

That's news to me and not the way I learned. No light until fixed, but my experience has been with 35mm in daylight tanks so no advantage really anyway.

 

[Les McLean]

I just watched the youtube clip on using the BTZS 4x5 deveoping tubes, and in this video the cap is removed from the tube after the developer and put in to a stop bath in the tube in room light,then the film is removed from the tube and tray fixed in room light! I was trained not to expose the film to light untill after fixing. any thoughts on this ?

I've used the BTZS tubes for the past 10 years after watching a demonstration by Fred Newman who did as you describe in your post. I have to say that I was extremely dubious about the outcome when Fred told me what he was about to do but was satisfied that it had no affect on the film when I inspected it after drying. I have used this method when developing my 5 x 4 film ever since and can confirm that there is no sign of fogging and deterioration at all on the film.

 

[jeroldharter]

I use BTZS tubes and I was squeamish about that. Once you put the film in the stop, exposing it to light does not matter because you will be putting the film into fixer which will remove any undeveloped silver whether it was exposed to light or not. Nevertheless, I would not hot dog and flip on the flood lights.

What I do is work under dim safelight. I process the tubes (up to 6 at a time) in a tempered water bath. Typically, each sheet of film will have a different development time individualized to the exposure if you are using the BTZS system. When the shortest development time is finished, I open the tube, dump the developer, and put the tube into a tray of stop bath (with the safelight on). I continue processing the other tubes until the longest development time is finished. In the meantime, I give the tubes floating in the stop bath tray an occasional spin. Some tubes soak in the stop for several minutes with the safelight on until the full run is finished.

Once all of the tubes are into the stop, I transfer them to the fixer. Some leave the film in the tubes, but I remove the film from tubes and finish the processing in a slosher tray. So I put up to 6 sheets of film in an 11x14 slosher tray of fixer, still under safelight. Not that the light is "safe" but just dim. After a bit of time in the fixer, I turn on the room lights and watch the film clear which is kind of fun. I have not had any problems with this and BTZS is a great system. I recommend doing the film test service from the View Camera Store which will give you all the data you need for the film of your choice for about $50. Saves a lot of time vs. DIY testing.

 

[bobwysiwyg]

Nice to know since I will be doing some (my first) 4x5 sheet film developing shortly. Thanks.

 

[David A. Goldfarb]

I can't see any good reason for turning the lights on before the film has cleared. Given the precision that BTZS claims in measuring densities to two significant figures, I found that video astonishing. What is the point of all that measurement and calculation, if one is going to risk an increase in base fog and even slight solarization, and for what benefit?

 

[Photo Engineer]

Well, there is another thing. Any silver halide in a light sensitive material will print out (turn to some form of silver metal) upon exposure to light. That is why you fix it. So, even if you could do what the example shows, you would be creating actual metallic silver from silver halide due to light exposure, and it cannot be removed by fixation in most cases.

As an example of this, take a small sheet of film or paper, and set it out in the darkroom light for a few minutes with a cardboard covering it. The uncovered part will darken. Fixing the film or paper will leave a small amount of colloidal silver behind which would have distorted the image if you indeed exposed film before proper stop and fix.

PE

 

[tim_bessell]

Doesn't the emulsion become desensitized somewhat during/after development?

I viewed the same video, made me curious! I don't use tubes, but rather open trays, so I just had to experiment. After several test negs went into the acid stop bath, I flipped on the safelight (7 watts) and finished processing. I could not detect and difference with my eyes. I should have measured density, but alas, I did not.

 

[pwitkop]

I had a professor at Brooks who demonstrated this in the zone system class, much to the astonishment of the class; I'd heard of it before so I got to look smart. I did ask about the silver printing out, it seems that under normal to dim artificial light, no noticable silver would print out in the time in the stop before. He said there was no difference in base fog, and I'm assuming since this was a long time Brooks faculty member, he'd read the negs on a densitometer not just by eye.

PE, I was under the impression that the particular silver created by printing out was subject to bleaching in hypo much more readily than silver created by developing out (more 'fragile' IIRC, is how I've heard it refered). First is this acctually the case (to any degree)? And second, if there's some truth to it would this help counteract any density formed by printing out?

Peter

 

[jeroldharter]

I can't see any good reason for turning the lights on before the film has cleared. Given the precision that BTZS claims in measuring densities to two significant figures, I found that video astonishing. What is the point of all that measurement and calculation, if one is going to risk an increase in base fog and even slight solarization, and for what benefit?

The point of testing and calibration is to make repetitive tasks easier the next time. Working with a dim safelight is much more pleasant than working in the dark (for me at least). And using the safelight in that manner really has no effect on the negative. The point of testing is to confirm that.

 

[Photo Engineer]

I had a professor at Brooks who demonstrated this in the zone system class, much to the astonishment of the class; I'd heard of it before so I got to look smart. I did ask about the silver printing out, it seems that under normal to dim artificial light, no noticable silver would print out in the time in the stop before. He said there was no difference in base fog, and I'm assuming since this was a long time Brooks faculty member, he'd read the negs on a densitometer not just by eye.

PE, I was under the impression that the particular silver created by printing out was subject to bleaching in hypo much more readily than silver created by developing out (more 'fragile' IIRC, is how I've heard it refered). First is this acctually the case (to any degree)? And second, if there's some truth to it would this help counteract any density formed by printing out?

Peter

Every emulsion reacts differently during development with respect to printout. Some become more sensitive to printout and some become less so. The point is that printout ""can" occur.

It is also true that the colloidal silver(s) (plural because they vary with respect to crystal type (bromide, cl/br, br/i and etc)) will be very sensitive to removal by hypo. But, this removal is depenant on the pH of the hypo and is more apt to take place in an acidic hypo than an alkaline hypo.

I have personally seen prints become yellow in hypo if the hypo is nearing exhaustion, a water rinse was used, and the lights were turned on early. Printout and development began anew when the lights went on.

So, your professor was right. Under ideal conditions of fresh stop and fresh acid fix, this should not be a problem, but under other conditions such as a fast developing paper, a strong developer, a water rinse and alkaline fix or weak fix, you get printout or the actual resumption of development.

If you don't believe this, there is another thread here about prints yellowing in the fix if the lights went on too early. It was within the last week.

There is lots more to be said on this subject, but you will not see it if you exercise prudence in use of solutions. (and lights)

PE

 

[pwitkop]

PE, you make a good point about fresh solutions, in much less than ideal circumstances I'm sure things could go wrong quickly. And I've seen printing out myself in the form of yellowing prints from turning on the lights too soon printing with a water bath and an alkaline fix, it's a very real phenomenon!

Peter

 

[sanking]

Doesn't the emulsion become desensitized somewhat during/after development?

I viewed the same video, made me curious! I don't use tubes, but rather open trays, so I just had to experiment. After several test negs went into the acid stop bath, I flipped on the safelight (7 watts) and finished processing. I could not detect and difference with my eyes. I should have measured density, but alas, I did not.

Yes, and that is in part why the BTZS procedures, which were first promoted by Phil Davis and now by Fred Newman, work. The BTZS procedures call for taking the cap from the tube and immediately placing it in an acid stop bath, in subdued room light. Any further development stops immediately when the film hits the stop bath. I then take the film from the tube and place it in the fixer, again in subdued room light. This procedure does not result in any increase B+F or maximum density over keeping the film in the dark through the fixer.

Sandy King

 

[Photo Engineer]

Sandy;

You are one of the people I would trust to do it correctly. As you see from my posts above, there are points at which things can go wrong and I have had it go wrong when I rushed things.

PE

 

[sanking]

PE,

I have made about every mistake you can make in the darkroom. About the best I can say is that so far those mistakes have not resulted in any permanent injuries.


Sandy

Sandy;

You are one of the people I would trust to do it correctly. As you see from my posts above, there are points at which things can go wrong and I have had it go wrong when I rushed things.

PE

 

[Marco B]

It is also true that the colloidal silver(s) (plural because they vary with respect to crystal type (bromide, cl/br, br/i and etc)) will be very sensitive to removal by hypo. But, this removal is depenant on the pH of the hypo and is more apt to take place in an acidic hypo than an alkaline hypo.

PE, I don't get your remark about the different forms of colloidal silver. The "crystal" types you describe (bromide, cl/br, br/i and etc) are actually the silverhalides? :confused:

These should be fixed out?

Or are you suggesting/explaining that during the print-out of the silver halide, the silverhalide actually decomposes in two components:

- Metallic silver
- Combined with a crystal form of bromide / chloride (shouldn't that be a gas?) / iodide

and maybe deposited in some sort of complex of the two.

Actually, this would make some sense, since the electrons are swapped between the silver and the halide. Although I still have some difficulty imagining it precisely.

Am I right to assume that the complex of metallic silver and neutral halides crystals (no electron charge) will NOT fix out in hypo? Meaning both the silver and the halides will remain in the image, probably slowly returning to some sort of equilibrium with their silver halide counterpart (at least when the halide doesn't escape in some sort of gas form (e.g. chloride gas as used on the WWI battlefields...)

 

[Photo Engineer]

Marko;

You have a fundamental misunderstanding of what is going on. No offence is intended but I apologize for that blunt statement in advance.

A developed silver image consists of filaments, tablets, rods, irregular clumps and etc. These result from different methods of development and different halide mixtures and give some degree of tone to the final silver image. They are fairly stable and consist of thousands or millions of silver atoms.

Colloidal silver can also be present. It consists of three to hundreds of atoms of silver (no one has counted them in this case or even in the case above) and they are finely divided. These form as printout when silver halide is exposed to light.

There is a third type formed from development which continues in the fix if the fix is exhausted, is alkaline, or the wash is poor and allows carry over of developing agent. This is a mixture of the two forms of silver above, and also is highly colored due to the formation of dichroic silver which is a near solid phase coating or mirror of silver in the emulsion. It comes from a high level of silver halide solvent redepositing silver in the presence of light and a reducing agent (light is not needed for this).

All of the above can be bleached by heavy fixation, especially the colloidal form.

There is no complex of metallic silver and neutral halides. The only complexes are charged.

I hope this helps a bit.

PE