Care to explain? There shouldn't be much difference whether a film is insensitive to red light or a filter absorbs it, yes?
Up until now I saw the main motivation for orthochromatic film in the fact that it can be manipulated while dark room safe lights are on, but I'm ready to learn ....
Using a 44 or 44A filter will give the same look as traditional ortho film. Traditional ortho stops recording at approximately 580nm, and at that wavelength the 44 transmits o% and the 44a transmits .1% of the light hitting the filter. That's from the Transmission of Wratten Filters pub by Kodak. It means you'll need to increase your exposure by 1-2 stops, depending on the wavelengths being photographed.
That will give you a more traditional look when developed for your style than if you try a new film and have to relearn its properties, wasting several shots in the process.
The silver structure is different for ortho films because it does not need to be sensitized to red spectrum light. The contrast filter may simulate some of the tonality (which, even then, is up for debate) but will do nothing to change the grain structure.
And the results you obtain when you try to develop the film under a red safe-light would most likely also disappoint.:whistling:
Safelights other than a very very dim green, and then for short times are still not good for pan films.
As far as the filter for the effect, if I recall correctly, Ansel Adams recommended the 44A to simulate the old ortho film look and feel with most pan films and the 47 for blue only in his book The Negative. It would seem, at least to me, that his recommendation would be valid. Even though the sensitivity to red exists, if the light doesn't, then nothing would be recorded where it was red. As the red sensitizing is accomplished by adding an agent to the emulsion, the grains remain unchanged either way. At least, that's my understanding.
I apologize if I'm misleading anyone, and if I'm wrong, I hope that someone can set me straight.
Michael R. apparently uses a dim red safelight with success.
Jesus, what a thread ...
I thought I said for pan films, but it turns out I only mentioned it not being good for them. Sorry for not being clear, I often have that habit.Quote:
Did you mean orthochromatic films? And why would you use green safelights for orthochromatic film?
Actually, using an incredibly dim green light allows for short adjustment times for the eye, which allows for rapid inspection of pan films to check development. Green light for ortho would be bad indeed.
For ortho, red is good, and for the old blue only films, a green light was used as the eye adapts quicker to green. Of course, for pan films, the distance, time, and brightness are all factors. Developing by inspection is definitely not worth the effort except for the most difficult of negatives, at least for me. Accurately judging densities in the dark is too tricky for me.
Plus, the heightened sense of anticipation in the dark is quite rewarding when you finish without peeking!