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  1. #1
    vanspaendonck's Avatar
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    Multiple flashbulb exposure of a room (how to -)

    I occasionally use Westinghouse #11 flashbulbs with my Crown Graphic, just for the heck of it, and I have more bulbs left than I could use up in the next years. So, I thought I might be interesting to replace most of the (screw base) light bulbs in my living room with #11 bulbs, mount the camera on a tripod and set the shutter on B or T, throw the main switch and...... Kabang!!!! Painting with light the quick and dirty way, you could say.
    This however raises a couple of questions:

    1. The bulbs are rated for 3-30 Volts. I wonder how they will react to 230 V AC.

    2. I wonder whether the lamp shades (all more than 10 inch diameter with an open top) can cope with the heat.

    (I guess I should sacrifice at least one flash bulb and an old lamp cum shade to find the answer to questions 1 and 2, but maybe someone has experience with this kind of setup.)

    3. This is the difficult bit: How do I calculate the exposure? I would like to avoid having to do a lot of bracketing at six flashbulbs per shot......

  2. #2
    David H. Bebbington's Avatar
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    Quote Originally Posted by vanspaendonck View Post
    I occasionally use Westinghouse #11 flashbulbs with my Crown Graphic, just for the heck of it, and I have more bulbs left than I could use up in the next years. So, I thought I might be interesting to replace most of the (screw base) light bulbs in my living room with #11 bulbs, mount the camera on a tripod and set the shutter on B or T, throw the main switch and...... Kabang!!!! Painting with light the quick and dirty way, you could say.
    This however raises a couple of questions:

    1. The bulbs are rated for 3-30 Volts. I wonder how they will react to 230 V AC.

    2. I wonder whether the lamp shades (all more than 10 inch diameter with an open top) can cope with the heat.

    (I guess I should sacrifice at least one flash bulb and an old lamp cum shade to find the answer to questions 1 and 2, but maybe someone has experience with this kind of setup.)

    3. This is the difficult bit: How do I calculate the exposure? I would like to avoid having to do a lot of bracketing at six flashbulbs per shot......
    1. They will explode with a bloody great bang and blow all your fuses! Bulbs are rated for 3 to 120 volts but not 230.

    2. Probably OK, as heat is of short duration only.

    3. Calculate exposure with guide number (allow 1/2 to 2/3 stop more if shooting neg film) and use tape measure to ensure all bulbs are the same distance from the objects they are illuminating. You could use a small camera or rangefinder to measure the distance.

    I have never used flashbulbs in the way you describe but had a lecturer at college who did. He was particularly graphic in describing the bloody great bang!

    Regards,

    David

  3. #3
    vanspaendonck's Avatar
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    Well I tried a bulb in a normal shaded lamp. No big bang, just the usual pop. The glass support for the electrodes broke off inside the bulb though and the fuse blew. I have automatic fuses, so I just had to reset the switch.
    I guess I could use these flashbulbs in normal lamp fittings without setting fire to the house (which is all wood, incidentally).

    Thank you for your thoughts about the exposure, but I am still not sure. The GN assumes that the bulb is in a polished 7" reflector next to the camera, which is very different from having about six bulbs at various distances in front of the camera.

  4. #4
    David H. Bebbington's Avatar
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    Quote Originally Posted by vanspaendonck View Post
    Well I tried a bulb in a normal shaded lamp. No big bang, just the usual pop. The glass support for the electrodes broke off inside the bulb though and the fuse blew. I have automatic fuses, so I just had to reset the switch.
    I guess I could use these flashbulbs in normal lamp fittings without setting fire to the house (which is all wood, incidentally).

    Thank you for your thoughts about the exposure, but I am still not sure. The GN assumes that the bulb is in a polished 7" reflector next to the camera, which is very different from having about six bulbs at various distances in front of the camera.
    What I should have added was that, as you say, the GN assumes a reflector. If you are not using a reflector, you probably need to give approx. 1 1/2 stops more exposure. Don't worry about working out exposure, this is ONLY a function of the distance from the flash to the subject, wherever this is - the distance from the subject to the camera makes no difference. When Philips sold a lot of flashbulbs, they used to have a display team which photographed buildings like the pyramids in Egypt at night with dozens of big flash bulbs (they used the pictures in their advertisements). All the bulbs were placed the same distance from the subject and gave perfectly even exposure.

    I am glad you are not getting a bang! My lecturer was talking about 50 years ago, before automatic fuses (circuit breakers) and when British circuits were protected by wire fuses of 30 or 40 amps or so. These took longer to blow!

    Regards,

    David

  5. #5
    dmr
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    My dad used to use those screw-in flashbulbs, the ones about the size of a refrigerator bulb. One of my brothers used to play pranks by putting one in a regular light socket, and, other than scaring the {expletive} out of whoever turned on the light, I just remember them as flashing more or less normally.

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    Quote Originally Posted by dmr View Post
    My dad used to use those screw-in flashbulbs, the ones about the size of a refrigerator bulb. One of my brothers used to play pranks by putting one in a regular light socket, and, other than scaring the {expletive} out of whoever turned on the light, I just remember them as flashing more or less normally.
    Yes, but are you in the USA, where the voltage is half the normal international standard? I suspect you must be, because when I was a boy, UK (and I believe, other European) bulbs were almost all bayonet cap (BC) not ES.
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    Quote Originally Posted by Roger Hicks View Post
    Yes, but are you in the USA, where the voltage is half the normal international standard?
    Huh? Are you certain there is a single international standard for household supply? See IEC 60038:1983.

    Does a flashbulb really burn any brighter at higher ignition voltages than at lower ignition voltages?

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    Quote Originally Posted by BrianShaw View Post
    Huh? Are you certain there is a single international standard for household supply? See IEC 60038:1983.

    Does a flashbulb really burn any brighter at higher ignition voltages than at lower ignition voltages?
    No, I said normal international standard, as found in most of the civilized world. The US and a few other countries use 110/120V but most use 220 to 240V. I say 'civilized world' because I'm not counting for example 80v DC as found in some of the Gilbert and Ellice (Ellis?) Island when I considered applying for a job there some 35 years ago.

    Nor did I say they burned brighter -- it would be odd if they did, as the light comes from combustion -- but merely that ES bulbs were rare in the UK and in those parts of Europe with which I was familiar as a boy, which led me to suspect that DMR lived in the US.

    I have never tried putting flashbulbs in household sockets, but as two people suggest that fuses blew/circuit breakers tripped on 230V and you seemed to imply that they did not when DMR's brother tried it, it does seem that they may blow/trip if you insert flash bulbs at higher voltages than 120.
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  9. #9
    dmr
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    Quote Originally Posted by Roger Hicks View Post
    which led me to suspect that DMR lived in the US.
    Yes, US, plain old AC house electricity. They would flash when turned on and I don't remember any blown fuses at the time. This would be late 50s and early 60s and I know the place we lived had screw-in fuses and not breakers back then.

    The bulbs I am talking about had a regular screw-in base the same size as a regular light bulb. These were smaller than any regular light bulb.

    He also had an adapter which would screw into the flash and accept and hold a bayonet bulb right in the center of the reflector as well.

  10. #10

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    Quote Originally Posted by dmr View Post
    Yes, US, plain old AC house electricity. They would flash when turned on and I don't remember any blown fuses at the time.
    Thanks for the confirmation -- and of course 'screw in fuses' are also indicative of the US.

    I was just interested in the idea that US fuses didn't blow and 220-240v fuses did.

    Cheers,

    Roger
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