Another, in my series of stupid noob questions.

[Tim k]

Stupid, if you know the answer, but its making me nuts trying to figure this out.

Part 1,
I was just reading (well, watching u-tube) that you can expose a negative to light as soon as the developing stage is over, just as it goes into the stop bath. This was a video on using btzs tubes.

If this is true, is it also true when developing prints?

Part 2,
When I open my brand new package of paper (ilford rc) in the dark, how do I know what side is up? The only thing I can find was to lick your fingers and see what side sticks? really?

The good news is, that I am making a little progress.

Thanks guys

[Ash]

1.

I'd not recommend you allow anything light-sensitive to see light until during/after fix. With some papers it will fog. With film you might get uneven development. I usually take the top from daylight dev tanks after a few minutes of fix.


2.

You use a safelight

[photographs42]

I suppose you could but why would you want to? You have a large investment in time with those negatives. Why risk degrading them by turning the light on a minute or two sooner?

You will learn to “feel” the emulsion side of the paper. It has a different texture.

Jerome

[Glenn Thoreson]

Don't expose your film to light until it's been in the fixer for at least a minute. In the olden days, developing was done by inspection using a dim dark green or red safelight. It takes a lot of experience to do that and you only have a few seconds to do it. With modern films and methods it's not only hazardous to your film, it's totally unnecessary. Under a safelight, RC paper has a distinctive mottled look on the emulsion side. The sticky finger test works, too. After a while, you'll get used to seeing it. Once you figure out which side is up you can mark the package so you know.

[Vaughn]

1. What Ash wrote.

2. Some RC surfaces are difficult to visually see the difference between front and back. Do the wet finger test...noting how the paper was orientated in the bag you took it out of. All the sheets will be orientated the same way (judge by the way the flap of the bag opens.)

Once you know which surface is which, another test is running your dry finger lightly over the surface of the paper. I know that the "N" surface of Kodak's RA4 paper (RC) will make a slightly different note than the other non-emulsion side (a slightly higher note if my memory serves me.). Won't work if you have music blasting away!:p

Vaughn

[Ole Tjugen]

1: Within certain limits, yes you can. As long as the light it's exposed to is very weak compared to the exposures in the deepest shadows (thinnest parts), both negatives and prints can take surprisingly much light before fixing. If you've been sitting in safelights/nolights for the better part of an hour, your eyes will be a lot more sensitive than any film yet made.

2: They just look different. Also the paper tends to be packed paper side out, so that it curls opposite in the middle of the pack. The "inside" is the emulsion side.

[SAShruby]

2. RC paper curls inwards on emulsion side. Same for FB.

Added: I guess Ole was faster than me.

[sanking]

In BTZS workshops taught by Phil Davis it was common practice to remove the caps from the tubes in room light, and plop them directly into the stop bath. This results in exposure of a few seconds. I have done this myself numerous times without any damage to the negative in terms of extra fog. In fact, it is my standard operating procedure for developing negatives in BTZS type tubes.

But please note the operating principles. Room light, and only a few seconds of exposure to room light.

Sandy King

[jeroldharter]

I use 4x5 BTZS tubes. when I open the tube to dump developer, I have a dim safelight on. I place the open tube into a tray of stop bath and give it a few spins and then leave the open end adjacent to the edge of the tray so it gets minimal light. In theory, I could use room light but sometimes the open tube sits in the tray for several minutes while the other tubes finish development so I use a safelight which is adequate.

When all tubes are in the stop bath, I pull the sheets of film out with safelight on and place each sheet into a slosher tray of fixer and then turn on the room lights. Have never had any problems with fogging which can be confirmed by densitometer.

[Jim Galli]

I'm surprised at what I'm seeing here. Just because you've poured off the developer doesn't mean it's all gone or that developing has stopped. If you flip lights on you are adding exposure with developer still present in some diminished form. I usually do not consider myself conservative but, I wouldn't do it. Once the stop bath has completely eliminated developer it is OK, but I still prefer to count to about 30 after it is in the fixer before the lights go on.

For finding the emulsion side of film in the dark, when the tall part of the film is going up and down the notch is on the right side. For paper you have to learn to 'see' the emulsion side with the dark light on.

[h2oman]

Glad someone is helping me out in the "noob questions" department!:D

[jeroldharter]

I'm surprised at what I'm seeing here. Just because you've poured off the developer doesn't mean it's all gone or that developing has stopped. If you flip lights on you are adding exposure with developer still present in some diminished form. I usually do not consider myself conservative but, I wouldn't do it. Once the stop bath has completely eliminated developer it is OK, but I still prefer to count to about 30 after it is in the fixer before the lights go on.

For finding the emulsion side of film in the dark, when the tall part of the film is going up and down the notch is on the right side. For paper you have to learn to 'see' the emulsion side with the dark light on.

I had the same concerns and some disbelief. But it really makes no difference.

[Tim k]

Thanks guys for the quick help.

I think I actually understand now, I thought perhaps I was missing something obvious. I usually make things harder than need be.

[Nathan Potter]

I agree completely with Jim above. I use only safelights near the end of the stop bath if the film is exposed to the room; that is non drum development.

I always remove one sheet of paper from a new packet then examine for the emulsion side under room light. Then I mark the envelope as to which side the emulsion is on. Thus I sacrifice 1/50 the cost of the paper (for a 50 sheet pack) to be sure I have it correct.

Nate Potter, Austin TX.

[sanking]

The OP question was about processing with BTZS tubes. There is a wide body of experience that comes out of BTZS workshops, and from the common practice of many photographers who develop film in tubes, including myself, that subjecting the film to several seconds of room exposure by removing the cap of the tube and then moving the tube to an acetic stop bath, does not result in any additional B+F.

I know that this flies in the face of much historical wisdom, but it is nonetheless true. It really does not matter who believed what. Anyone who has a working transmission densitometer can easily verify this for himself/herself.


Sandy King






I'm surprised at what I'm seeing here. Just because you've poured off the developer doesn't mean it's all gone or that developing has stopped. If you flip lights on you are adding exposure with developer still present in some diminished form. I usually do not consider myself conservative but, I wouldn't do it. Once the stop bath has completely eliminated developer it is OK, but I still prefer to count to about 30 after it is in the fixer before the lights go on.

For finding the emulsion side of film in the dark, when the tall part of the film is going up and down the notch is on the right side. For paper you have to learn to 'see' the emulsion side with the dark light on.

[Brian Ellis]

Those who told you that you have to stay in the dark until film is in the fix are wrong. You can turn on the lights with the film in the stop bath. Guess why they call it STOP bath? That's right - it STOPS development, like instantaneously. And developed film is far less sensitive to light than raw film. So if you move reasonably quickly, and don't shine a spot light directly on the film, you'll be fine with the lights on in the stop bath. That's how Phil Davis taught it in his workshops and that's how I've been doing it for about 14 years, through a few thousand negatives, and never had the first problem.

I've always assumed that the emulsion side of paper is facing up when you open a box. But there are a couple ways to double-check. The ends of the emulsion side tend to curl up. So unless the paper is perfectly flat, which it seldom if ever is, that's another way to tell. And unless you're using matte paper, the emulsion side will be smoother than the back. That's another way.

[Jim Graves]

Man ... I learn something new every day here ... thanks for asking the "stupid noob question."

[Allen in Montreal]

edit: on reading Sandy King..... I have never used BTZS tubes...statement withdrawn.


........

Part 1,
I was just reading (well, watching u-tube) that you can expose a negative to light as soon as the developing stage is over, just as it goes into the stop bath. This was a video on using btzs tubes........

[Tim k]

Man ... I learn something new every day here ... thanks for asking the "stupid noob question."

Hey, it just comes natural to me.

[Nathan Potter]

This is an interesting thread. As I read most comments it appears that there is a vague consensus about when it is possible to expose a film to light during the processing stage. I believe some seem to think that it is wise not to do this during development; some may believe it's OK just after development if the light is of short duration or is dim; and finally some believe the film should be in the stop bath prior to exposure to any light. I had thought that exposure to any light might best be left to post development at least after immersion into a stop bath.

Now given the variables involved, that is the multitude of developer types and film emulsions as well as the dose of original exposing light it may be difficult to quantify exactly what is safe except by doing an actual test using the materials under question.

But some sense can be made of this by recalling how an image is recorded in the emulsion and how the developer works to form a visible image during development.

B & W emulsions are made from silver halide crystals imbedded in gelatin. Other chemistry may be added but the simplest implementation consists of a halide and silver nitrate infused into the gelatin binder. Through a heat ripening process, tiny, say 0.2 um. to few um. sized crystals of silver halide are formed. When this emulsion is exposed to light photolysis occurs wherein metallic silver is formed generally at the surfaces of the tiny halide crystals. However there is not much silver formed and no readily visible image is in the film. Now when the latent image consisting of that very small amount of metallic silver is immersed into developer a very large part of the remaining silver halide crystal is reduced to metallic silver and if we could see this we would see density building before our eyes first in those areas that received more light during exposure.

Microscopically the latent image (the small amount of silver formed during the initial exposure) catalyzes the reaction with the developer as the developer becomes absorbed into the gelatin. Thus the action of the developer increases drastically the formation of metallic silver in what might be called a galvanometric reaction. The silver amplification can be 10^6 to 10^8.

Well how might this view of the development process impact the comments in this thread? It seems clear that as long as there is developer present in the emulsion it could be risky to let any amount of light hit the film unless the original exposure was so minimal that all of the silver that could be formed during development was brought to completion (maximum density was achieved). This is generally not the case but could be depending where on the sensitometric curve one was operating.

If the film is removed from the developer but not placed in the stop bath the only remaining volume of developer that could catalyze more silver would be that remaining in the emulsion. I believe that this volume is pretty small and would become exhausted quickly so the amount of additional silver produced would be the sum of the parasitic exposing light and the residual developer available before exhaustion.

Lastly once the film is plunged into the stop bath all additional silver buildup will cease as soon as the stop has neutralized the remaining developer in the gelatin emulsion. I'm not certain of the time required for this but may be almost instantaneous to several seconds.

Given the variables of a wide range of emulsions and developers and original exposue doses (W/sq.cm.) I'd say do a test to determine the light tolerance for your particular process. IMHO I've no reason to doubt most of the comments so far in this thread - and some are based on real experience.

Nate Potter, Austin TX.

[sanking]

It should again be noted that the issue of subjecting the film to room light has been advocated only by those familiar with developing in BTZS type tubes. With this method we remove the cap, and immediately plop the tube with the film in it, into the stop bath. The film would receive no more than a few seconds exposure before it hits the stop bath, and then only from one end of the tube.

One assumes that we are talking about an acetic stop bath, not a water stop bath. It is the highly acidic stop bath that stops development immediately. With a water bath there will continue to be development for up to a minute or so after the film is placed in the water bath. If you are working with a water stop bath I would caution that subjecting the film to any light before it goes into the fixer will probably result in some fogging.

Finally, bear in mind that by the end of the development cycle film is much less sensitive to light than it was at the beginning, and less sensitive yet if you are using a pyro staining developer.

Sandy King







Lastly once the film is plunged into the stop bath all additional silver buildup will cease as soon as the stop has neutralized the remaining developer in the gelatin emulsion. I'm not certain of the time required for this but may be almost instantaneous to several seconds.

Given the variables of a wide range of emulsions and developers and original exposue doses (W/sq.cm.) I'd say do a test to determine the light tolerance for your particular process. IMHO I've no reason to doubt most of the comments so far in this thread - and some are based on real experience.

Nate Potter, Austin TX.

[Nathan Potter]

Well said Sandy. I had been assuming an acetic acid stop bath for general use. The BTZS tube will significantly protect the film from incident light during a short transfer to the stop bath but never realized it would be essentially safe to leave a cap off and avoid minimum fogging of the neg.

Nate Potter, Austin TX.