When is Film Light Safe?

Gerald C Koch said:

This second light is best used with a foot switch so it can be turned on for very brief periods to check the extent of development. Most of the time this second light is left off. Whenever I have developed by inspection this system has worked very well.

Click to expand...

IMO this is crucial. In fact, when I do use DBI, I do everything in complete darkness, and only switch on the inspection light for a very short time.

Yes, the green safe light is VERY dim, but if it's OFF until you do your inspection, your eyes are more than prepared for its low levels when you do use it.

Bob Carnie said:

I would recommend not using any inspection method but rather use time temp method of development. But this is my opinion only and there are may options for you to pursue.

Click to expand...

For me, this is a key point as well. I do understand that there are times that you may be dealing with a film for which you don't have a firm development time, but once you have that nailed down, that mystery should be solved. I have read many times here on APUG that processing film is the science and making prints is the art. If you are really that comfortable tweaking negatives, more power to you; if you have that skill, I don't doubt that you will be able to reap good results from it.

I used to have a boss who said "there is more than one way to skin a cat" - in his case, it meant to stop doing things my way and do them HIS way, but to me in the realm of the darkroom, it means that everyone finds their way of achieving the results that please them best. If DBI works for you, do it. Find ways to minimize fogging and get a negative you can place between your light source and your paper and have fun.

Cheers,
Tom

Photo Engineer said:

...don't resume development after a wash or stop as they alter the way development takes place.

Click to expand...

Then what's the methodology of "development by inspection"?

- Leigh

Leigh B said:

Then what's the methodology of "development by inspection"?

- Leigh

Click to expand...

It is like baking a cake: you keep peeking at it (in the original developer) until it appears done.
The references to stop and fixer came up because of discussions concerning when it was generally safe to expose the film to light.

Yep, what Matt said. You wait until you think it is almost done, and then peek at it to check it out. Keep going until it is done. However, I find it useless for most due to the dim light and the appearance of the unfixed image. Many are not sure what represents "doneness" and it takes a long time to learn. Most don't have the time and money to waste and would be better off using the correct time/temp for the film.

PE

MattKing said:

It is like baking a cake: you keep peeking at it (in the original developer) until it appears done.

Click to expand...

Oh, OK.; Seems kinda stupid.
I just use time and temperature, and properly expose the film in the first place.

But I've only been doing this for 65+ years, so what do I know?

- Leigh

Leigh B said:

Oh, OK.; Seems kinda stupid

Click to expand...

nope not stupid at all. HCB's film was DBI from what i understand. and plenty of people "used to" do it, and still do it. from what i remember karsh's film was DBI, but he used a different method.

if you follow the links to michaelandpaula.com that were posted earlier in the thread
you will be able to read exactly how to do it. as mentioned a few times, the light goes on for a few seconds, you look
for highlights and from experience you know if it is done or needs a little more time in the developer. you do it out of the developer
not out of anything else, maybe a water rinse, that won't do much but keep developer from dripping everywhere.
its like a lot of things in photography ... like not using a light meter but knowing the light and setting your camera's fstop/shutter speed
through your experience of the same or simliar situations. some people find that to be useful, others like using a meter. DBI is useful
as toffle said, if you don't have an idea of what your time might be, lets say, with expired film or some new bregger film you haven't used with
lets say pyro510 and you have a ballpark development time but you aren't sure. DBI will give you a better idea if you have the experience to know
what it looks like when it "looks right" and it takes some time and film and developer to figure that out.
if you ever use xray film or ortho+ film you can study how it looks when it is getting done, since you can process those film by red safelight,
and use your knowledge of that emulsion to help if you ever get a green light and DBI with pan film.

Time and temperature development assumes that the film was correctly exposed. Often this is not the case with simple cameras. Add to this film of unknown origin or age and unusual lighting situations where metering cannot be done. So it can be useful to know how to use inspection. As John pointed out it was popular in the not too distant past.

jnanian said:

nope not stupid at all. HCB's film was DBI from what i understand. and plenty of people "used to" do it, and still do it. from what i remember karsh's film was DBI, but he used a different method.

Click to expand...

Urgent Press Release...

This is the 21st Century.

I'm not really interested in what folks did decades ago.

- Leigh

it has nothing to do with decades ago, people do this today ( i might be doing this tonight )

jnanian said:

it has nothing to do with decades ago, people do this today ( i might be doing this tonight )

Click to expand...

It's all a matter of perspective.

Some folks like to shoot barrel lenses and 19th Century gear.

- Leigh

not really a matter of perspective, its a matter of knowing the time and temperature for processing your film ... if it isn't documented

jnanian said:

not really a matter of perspective, its a matter of knowing the time and temperature for processing your film ... if it isn't documented

Click to expand...

If you don't know what film you're developing, use Diafine.

5 minutes each in Part A and Part B regardless of what the film is (B&W obviously).
And it doesn't care about temperature (within 72 to 85 or so degrees F).

- Leigh

Decades ago, film had an ISO (or ASA) of about 10 - 80. Today we are talking over 100 ISO.

Have fun and do what works for you.

PE

Leigh B said:

If you don't know what film you're developing, use Diafine.

5 minutes each in Part A and Part B regardless of what the film is (B&W obviously).
And it doesn't care about temperature (within 72 to 85 or so degrees F).

- Leigh

Click to expand...

glad it works for you
i've never used it
and never plan on it ...

It appears you find coffee to be better than a real developer.

It probably tastes better.

- Leigh

It is also possible desensitize the film before development. Various dyes have the ability to substantially lower the light sensitivity of films allowing the use of much greater illumination. At one time Kodak sold a desensitizer concentrate. The stock was diluted and used as a prebath before development. Dyes mentioned are pinacryptol green, safranine, phenosafanine and basic scarlet N. The following article contains a large amount of information.

http://atelierelealbe.eu/proiecte/bw-formula/articles/desensitizing-of-photographic-emulsions/

Leigh B said:

It appears you find coffee to be better than a real developer.

It probably tastes better.

- Leigh

Click to expand...

yes i do, coffee based developer are very real and work very well,
i have been using them for over 10 years, and have processed thousands of sheets/rolls of film/paper using it.
i don't usually drink the coffee i roast for developer, i get the coffee i drink off of amazon and it is
shipped to me 5# at a time every 2 or 3 months. i have had it thought, its not bad for sumatran coffee, but
i find indonesian coffee to be too earthy for my tastes and would rather drink something brighter and more acidic.

best of luck with your photography

Gerald C Koch said:

Dyes mentioned are pinakryptol green

Click to expand...

i believe that is the dye i was talking about that karsh's lab used... i could be wrong though.

Photo Engineer, can you tell the pinacryptol white chemical formula is? Raoul Dupont had made reversal analysis and prove that is 1,7-antraquinone disulfonate Na-salt, but there are opinions that its trisulfonate or smth else. Is there more effective desensitizer? Is there such chemical compound as "pinacryptol pink"?

http://delibra.bg.polsl.pl/Content/21477/BCPS_22995_1942_Chemisches-hb2-nr24.pdf (last page)

I mainly use BTZS tubes. I have a 25W tungsten bulb on when the film goes into the stop. The light hangs about a metre from the stop bath. I pull the film from the tube after the stop is complete, and slide it into the fix. I've never had a problem.

dE fENDER said:

Photo Engineer, can you tell the pinacryptol white chemical formula is? Raoul Dupont had made reversal analysis and prove that is 1,7-antraquinone disulfonate Na-salt, but there are opinions that its trisulfonate or smth else. Is there more effective desensitizer? Is there such chemical compound as "pinacryptol pink"?

http://delibra.bg.polsl.pl/Content/21477/BCPS_22995_1942_Chemisches-hb2-nr24.pdf (last page)

Click to expand...

There are pinacryptol white, yellow (CAS 25910-85-4), and green (19220-17-8). Never heard of a pink. The green seems to be less effective than the yellow.

The pathetic Bing search engine seems more interested in selling me white paint rather than supplying information on pinacryptol white!

I am not familiar with any of these. They were mentioned in several lectures at EK along with admonishment not to use them for reasons given before.

Sorry.

PE

Ok, thanks for answers.

How about never. Is never good for you?

Petraio Prime said:

How about never. Is never good for you?

Click to expand...

that would be good, if it was true, but it isn't
( and never has been )

jnanian said:

that would be good, if it was true, but it isn't
( and never has been )

Click to expand...

Panchromatic film? Never.