When is Film Light Safe?

analog65 · Apr 7, 2017

I wanted to make sure I am thinking correctly before I develop some sheet films.

It is my understanding that film is relatively not sensitive to light after the development stage.

I ask this question because I am going to be developing some Ilford HP5 B&W sheet film in trays and I wanted to check the negative with a safelight for a few seconds before I put them in my stop bath and fixer.

Can I leave on my safe light on during the stop bath and fixer stages, or do I need to turn it off?

Thanks!

Leigh B · Apr 7, 2017

You cannot turn the safelight on at all until the STOP bath step is FINISHED.

- Leigh

jim appleyard · Apr 7, 2017

You can indeed use a safelight while developing. Google "development by inspection". There are useful articles by good photographers like Michael & Paula and Ed Buffaloe (Unblinking Eye).

Petraio Prime · Apr 7, 2017

analog65 said:
I wanted to make sure I am thinking correctly before I develop some sheet films.

It is my understanding that film is relatively not sensitive to light after the development stage.

I ask this question because I am going to be developing some Ilford HP5 B&W sheet film in trays and I wanted to check the negative with a safelight for a few seconds before I put them in my stop bath and fixer.

Can I leave on my safe light on during the stop bath and fixer stages, or do I need to turn it off?

Thanks!

When the film is out of the fixer and washing. Unless you are using ortho film, which can be inspected under a red light.

Gerald C Koch · Apr 7, 2017

Kodak once advised that film can be viewed with a dim green safelight for a few seconds when development is at least half completed. This depends on the self masking of the partially developed negative. You should conduct a few tests. Use a Kodak Brownie safelight model B or equivalent with a 7-1/2 watt bulb or less. Minimum distance would be three feet between the safelight and the film.

http://www.studiolighting.net/items...ew-in-Safelight-Vintage-D87_351920246358.html

Orthochromatic film can always be developed using a red safelight.

Mainecoonmaniac · Apr 7, 2017

Leigh B said:
You cannot turn the safelight on at all until the STOP bath step is FINISHED.

- Leigh

Nope. Film after the stop bath is still light sensitive. You'll need to put it in fixer which removes any unexposed silver halides. The rule for fix time is twice the time it takes the film to clear.

https://en.wikipedia.org/wiki/Photographic_fixer

Leigh B · Apr 7, 2017

Mainecoonmaniac said:
Nope. Film after the stop bath is still light sensitive.

Yes, it is still light sensitive.

But the fixer will remove all remaining halides regardless of whether they've been exposed or not.

- Leigh

analog65 · Apr 7, 2017

I really appreciate the responses, but I am confused. Isn't my question a matter of science and not opinion? How can there be different answers to the same question?

Mainecoonmaniac · Apr 7, 2017

analog65 said:
I really appreciate the responses, but I am confused. Isn't my question a matter of science and not opinion? How can there be different answers to the same question?

I hope this helps. But as you can see, your film is no longer light sensitive after the fixing bath.

bdial · Apr 7, 2017

It is relatively insensitive by the time the development is complete, but you are risking fogging it or "solarizing" it if it's exposed to white light before getting in the fixer.
Inspecting with a safelight is possible per the reference Gerald posted, Ilford may have instructions that are specific to their films.
I often turn on the lights after the film is in the fix for a minute or so when I'm doing sheet film in open tanks. There is no problem in doing that as long as the film gets fixed completely.

Photo Engineer · Apr 7, 2017

If you turn light on, in an amount or of the color(s) the film is sensitive to, you can indeed cause bad things to happen. This is mainly a printout of silver metal that forms in a positive image over the negative image. Use of DBI is determined to be safe only by running tests of your workflow beforehand with non-critical images.

The type of light that can be used depends on the sensitivity of the film, such as Ortho needs a dim red safelight while many PAN films can tolerate a dim green safelight. This is only for a short time as is noted in Kodak publications.

As film speed goes up, the time and intensity of any exposure to light goes down.

In my many years working in this field, I have found that DBI is not very useful, at least to me.

PE

Mainecoonmaniac · Apr 7, 2017

PE is the authority. I'm slowly learning how to develop with a film safelight. Reading the highlight density with the milky base take some getting used to. But I try to keep my dim green safelight about 2' away from the film. I've heard some old timers develop under a safelight pretty accurately. I have a ways to go. But here's an article on the process I read a couple of years ago when I started to learn.

http://www.michaelandpaula.com/mp/devinsp.html

Cheers!

MattKing · Apr 7, 2017

Clearly there aren't any devotees of BTZS on this thread.
Development by inspection is possible, but the safelight is very dim, and the technique requires practice.
But more importantly, the question isn't whether or not the film is still sensitive to light, but rather whether exposure to light will affect the results.
The film is sensitive to light when it is fully immersed in the stop bath and all the developer is neutralized, but even if that light affects any of the silver halides in the film, nothing will come of that affect unless you later introduce that film to another reducing agent - i.e. put it back into the developer.
Mostly, we don't put the film back into developer after stop bath. Instead, we put it into fixer, which happily removes all of those exposed but not developed silver halides. If we did decide to put the film back into the developer, it would be a good idea to have a two bath setup, because the residual stop bath in the film isn't good for the developer.

Photo Engineer · Apr 7, 2017

Here is a hint that might work for you if you use DBI.

Look at the back of the film. It is not completely developed until you see an image on the back of the film. This assumes the AH dyes wash out well. I test this part in the light sometimes.

Following Matt's suggestion, you can stop development with a stop, then inspect, then WASH and resume development, but remember, the film can still be fogged when inspecting, so the light restrictions still apply. It is just that you are "safer".

PE

removed account4 · Apr 7, 2017

Mainecoonmaniac said:
Reading the highlight density with the milky base take some getting used to. But I try to keep my dim green safelight about 2' away from the film. I've heard some old timers develop under a safelight pretty accurately. I have a ways to go. But here's an article on the process I read a couple of years ago when I started to learn.

http://www.michaelandpaula.com/mp/devinsp.html

Cheers!

that link is the best
and as mentioned reading the highlights takes a bit of getting used to.
unless you are using ortho or xray film, or liquid emulsion on plastic or glass
you don't want to be using a safelight, except for the green one, for short amounts of time.
i've read ( i would like to say that it is wrong, but who knows maybe they know best ? )
that some people have used a regular red safelight to look at tmax film, but to me it sounded like
a great way to ruin film to me.

good luck !

analog65 · Apr 7, 2017

Just wanted to say thank you to everyone for helping out. I appreciate it.

jim appleyard · Apr 7, 2017

Maybe you can use red, IDK, but green is recommended because it's the color we can see in low light levels.

Toffle · Apr 7, 2017

I have, in the past developed by inspection as per the Kodak recommendations with a green safe light without problems. Once I had my process down to the point that I knew I could trust the results without "peeking", I tended to rely more on time and temperature to judge development. Tray development in absolute darkness has its own meditative Zen vibe to it which I found quite pleasing. Since then, though I hve switched from tray development to a Combiplan tank, so inspection is not really practical. I have good intentions of shooting some 8x10 again later this spring, so we'll see if I'm tempted to peek at my results.

Gerald C Koch · Apr 7, 2017

I started in photography using a Kodak ABC Darkroom kit. Because I had no timer development of Verichrome was by inspection. It does require a bit of practice evaluating the negatives.

Photo Engineer · Apr 7, 2017

Do not ever ever use a red safelight with pan film!

PE

removed account4 · Apr 7, 2017

jim appleyard said:
Maybe you can use red, IDK, but green is recommended because it's the color we can see in low light levels.

i have always been told that a red safelight, no matter the panchromatic film is a no-no,
and when people have suggested its use i have mentioned this ( but for a weird reason
they insisted with certain films it was OK, ( i still don't get it or know if they just said this stuff, or they did it and it was OK )
.. i'd errr on the side of caution, as you said the green WE can see from all reports the red the FILM can see ..

Leigh B · Apr 7, 2017

jnanian said:
i have always been told that a red safelight, no matter the panchromatic film is a no-no, and when people have suggested its use i have mentioned this ( but for a weird reasonthey insisted with certain films it was OK, i still don't get it or know if they just said it or they did it and it was OK )

Red should be fine with ortho film, but not with panchromatic.

Silver halide photographic emulsion is naturally sensitive to blue and ultraviolet.

It requires chemical modification to enhance sensitivity to longer wavelengths (toward red).
Lacking that modification it's ortho. (I don't know the proper terminology.)

- Leigh

Arklatexian · Apr 7, 2017

analog65 said:
I really appreciate the responses, but I am confused. Isn't my question a matter of science and not opinion? How can there be different answers to the same question?

Science or opinion? Science (and experience) tells me to develop the panchromatic films in total darkness until AFTER fixing. I tried the Kodak way with a dark green safelight filter. It was so dark in the darkroom that I could not see the film though I could feel it in my hand. I moved the film closer and closer to the safelight until I could see the film go completely dark. This was not opinion as when I stopped, fixed and washed the film, sure enough, it was completely fogged. But don't listen to me. Try the same thing with your film and see what happens. I never tried it again and I doubt you will either. Now Ortho film under a red safelight is another matter.......Regards!

Ricardo Miranda · Apr 8, 2017

analog65 said:
I wanted to make sure I am thinking correctly before I develop some sheet films.

It is my understanding that film is relatively not sensitive to light after the development stage.

I ask this question because I am going to be developing some Ilford HP5 B&W sheet film in trays and I wanted to check the negative with a safelight for a few seconds before I put them in my stop bath and fixer.

Can I leave on my safe light on during the stop bath and fixer stages, or do I need to turn it off?

Thanks!

This is what Ilford says about HP5+:

Safelight recommendations
Handle HP5 Plus film in total darkness. For very brief inspections during processing, use the ILFORD 908 (very dark green) safelight filter, with a 15W
bulb, fitted in a darkroom lamp (such as the ILFORD DL10 or DL20). Do not allow direct lighting from the safelight to fall on the film.

revdoc · Apr 8, 2017

My experience: I take developed film out of the tube in room light and slide it into the fixer. I don't get fogged negatives.

It would be totally different if I put the neg back into the developer after exposing it to room light. I would expect a black negative from that.

When is Film Light Safe?

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