Note to those who may not know: The GN table images, above, are for TUNGSTEN film speeds. Daylight film speeds may differ. Also, the tables that reference fim brands/types are likely not the same speed as the same film/type made today. So don't forget to factor in all of the changes between the film of the flashbulb era and today; check your GN calculations carefully.
Note to those who may not know: The GN table images, above, are for TUNGSTEN film speeds.
“b” bulbs are, if any, only a smidgen slower than the non-blue ones.
That was my only point about TUNGSTEN film speeds. It has nothing to do with the color of the bulb as insinuated in post #27. In this discussion, we don't know what film was being used, although one can assume that it was B&W since a clear bulb was used.But for speed of course the spectral sensitivity of the film must be taken into account.
25% less emission (Philips data)
But for speed of course the spectral sensitivity of the film must be taken into account.
That was my only point about TUNGSTEN film speeds. It has nothing to do with the color of the bulb as insinuated in post #27. In this discussion, we don't know what film was being used, although one can assume that it was B&W since a clear bulb was used.
The difference between tungsten and daylight film speeds is generally slight so it doesn't make a huge difference. As I'm sure that you will agree, even slight it could be one of many valid considerations when trying to adapt old data guides to modern film.
A few random examples:
- KODAK PLUS-X Reversal film, 7276. Daylight, EI 50, Tungsten, EI 40 B&W.
- KODAK TRI-X Reversal film, 7278. Daylight, EI 200, Tungsten, EI 160 B&W.
- PLUS-X Panchromatic Negative film, 4231 35mm. Later changed to 5231. Daylight, EI 80, Tungsten, EI 64.
- EASTMAN RP Negative film, 7229. Daylight, EI 250. Tungsten, EI 200.
- EASTMAN XT-Pan Negative film, 5220 Daylight, EI 25. Tungsten, EI 20.
- etc
So according to this the output is nigh on halved. Can’t be right. The filtering doesn’t look that strong.
Fortunately it’s relatively easy to remove the film with a sharp knife should you want it.
The speed of the film, daylight and/or tungsten, is independent of the color of the bulb. You are talking about matching the light source to the film type. I am talking about the speed rating of the film. Different discussions.
If you doubt the data, bring some different data to the table. About 1 stop difference has been my experience as a flash bulb user.
Most of us discarded our flash guns and flash bulbs along with button-up boots and wing collars. If you have either, sell them on Ebay for a small fortune, and go on a world cruise with the proceeds...
Flash in this day and age is, as I see it, 99.999% electronic. You can do so much more with it. Those old Graphic/Graflex flash guns used bulbs the size of Edison light globes, and they (the former) tended to explode at times, with dramatic responses from your (live) subjects. They nowadays also cost the price of a small car. They are now entirely museum pieces, not easily used photo accessories.
With a little effort with electronic flash you can quite easily duplicate the Vampire White face gloss and Scared Rabbit (aka Deer In The Headlights) Look, like in those 1940s news photographs. (= Weegee.)
Fortunately it’s relatively easy to remove the blue plastic film with a sharp knife should you want it.
But by this you also remove the safety feature of the small, more modern bulbs.
It does, since the “b” bulbs are tuned for daylight film.
Of course they are… blue filtered to accommodate tungsten light with daylight-balanced film; we all agree on that.
We’re talking past each other, it seems. I’m talking about FILM speed (ASA/ISO). You keep talking about BULB speed (GN or other measure of light output).
My point is rather simple. The tables generally show tungsten film speed. Modern film is identified with DAYLIGHT SPEED rather than identifying both daylight and tungsten speeds as they did in the past and examples shown in my earlier post, above.
Deep sigh. This really doesn't help @backseatpilot at all... talking nits so I'll leave the conversation. Bye.
I've never used flash bulbs, except as a joke in a light fixture, but you need to think of exposure differently when dealing with flash, whether it is bulbs or electronic. The aperture is what gives the correct exposure with the flash output. The shutter speed determines the ambient exposure. The only reason to shoot with a flash at 1/500 is if you are outside and that is your only option. Of course with bulb flash the shutter speed is a factor, but the aperture/shutter speed effect is the general rule.
Not correct for bulbs. There you can control flash strength with shutter speed too.
Not correct for bulbs. There you can control flash strength with shutter speed too. And ambient fill will always be about the same until you get below 1/30 or so.
That’s both a strength and a drawback with bulbs.
Bulbs remote radio triggered is where they really start to sing.
Technically speaking, you can't control flash strength with shutter speed, but can elect to use only a portion of the light energy put out by the flash by choosing a faster shutter speed/shorter exposure time than the duration of light output.
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