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robcruickshank
Joined: 25 Feb 2008
Posts: 19
Location: toronto, canada
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glennfromwy
Joined: 29 Nov 2001
Posts: 903
Location: S.W. Wyoming
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 Posted: Tue Dec 09, 2008 2:08 am Post subject: |
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A couple of things to ponder and possibly further confuse the issue. Blue bulbs need one stop larger aperture than clear bulbs. 'Twas always thus. Most guide numbers you will find are for Weston speeds. That doesn't help much. The ASA guide numbers you will find won't be accurate either. When speed ratings were updated around 1960 some time, film speed ratings were upped one to two stops, depending on the film, and called ISO ratings. Confused yet? I am. Oh, the 2B bulb is a different design than the 22B. The 2B is useable with focal plane shutters. Another thing I've noticed with blue bulbs and modern color negative film - you may, and probably will, get a definite blue cast to your pictures. Modern film has a different color balance than the old stuff, it seems. I would save the bulbs for B&W if color cast is a problem for you.
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Glenn
"Wyoming - Where everybody is somebody else's weirdo" |
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robcruickshank
Joined: 25 Feb 2008
Posts: 19
Location: toronto, canada
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| Posted: Tue Dec 09, 2008 2:32 am Post subject: |
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| glennfromwy wrote: | | Most guide numbers you will find are for Weston speeds. That doesn't help much. The ASA guide numbers you will find won't be accurate either. When speed ratings were updated around 1960 some time, film speed ratings were upped one to two stops, depending on the film, and called ISO ratings. Confused yet? I am. |
I don't think I've ever seen guide numbers in Weston units, most of the bulbs I have (and that's a rather stupid amount!) give GNs in ASA and feet. Do you have any packages that have Weston units on them?
Technically, ASA and ISO arithmetic speeds should be the same, although I wouldn't doubt that some brands of film have changed theirs. And yes, the colour balance can be quite strange. |
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glennfromwy
Joined: 29 Nov 2001
Posts: 903
Location: S.W. Wyoming
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| Posted: Tue Dec 09, 2008 3:53 am Post subject: |
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I probably do have some bulbs with Weston speed ratings. Those would be very old bulbs. I probably should have omitted the Weston speeds comment, though, as there are not likely to be many of those around. I have well over 1,000 bulbs. They are all stashed in the attic amongst various other vintage photography items and would be very difficult to get at. Please excuse me if I don't want to dig through all that stuff. In any event, if you have bulbs with ASA guide numbers, just give one stop less exposure than listed. That should put them on the ISO scale. Some old exposure tables I've seen do not always take the film speed into consideration, which seems very strange to me. I think the best way to go about it is to test and test again. If you use ISO 400 with some of these you could probably get a picture of Denver from Los Angeles. These things pack a wallop that no modern flash attachmnt can equal.
As an interesting historical note: The earliest bulbs had no guide numbers to work with and could not be synchronized. They were too erratic. They were used for open flash only and exposure was by testing and educated guess. Bulbs became available on the U.S. market in 1930. Earlier in the UK. They weren't reliable enough in speed to start using synchronizers until the late '30s. The synchronizer came about through the experiments of the photographers of the day and they were also responsible for the improvements to the bulbs.
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Glenn
"Wyoming - Where everybody is somebody else's weirdo" |
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mopar_guy
Joined: 07 Aug 2008
Posts: 126
Location: Washington, the State
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| Posted: Tue Dec 09, 2008 4:23 am Post subject: Old bulb and new film |
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OK,
Here's what I was thinking:
1) I acquired a couple of 3x4 speed graphics that nobody seems to think can be used (that is obsolete).
2) get some 8x10 T-Max and Portra and cut it into 3 1/4 x 4 1/4 (I get five out of an 8x10)
3) find a 4x5 enlarger (with a 135mm lens and 3x4 film holder)
4) use some old flashbulbs
5) make some photographs in B&W and color
You can all call me crazy. 
Dave |
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robcruickshank
Joined: 25 Feb 2008
Posts: 19
Location: toronto, canada
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| Posted: Tue Dec 09, 2008 4:26 am Post subject: |
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| glennfromwy wrote: | I probably do have some bulbs with Weston speed ratings. Those would be very old bulbs. I probably should have omitted the Weston speeds comment, though, as there are not likely to be many of those around. I have well over 1,000 bulbs. They are all stashed in the attic amongst various other vintage photography items and would be very difficult to get at. Please excuse me if I don't want to dig through all that stuff. In any event, if you have bulbs with ASA guide numbers, just give one stop less exposure than listed. That should put them on the ISO scale. Some old exposure tables I've seen do not always take the film speed into consideration, which seems very strange to me. I think the best way to go about it is to test and test again. If you use ISO 400 with some of these you could probably get a picture of Denver from Los Angeles. These things pack a wallop that no modern flash attachmnt can equal.
As an interesting historical note: The earliest bulbs had no guide numbers to work with and could not be synchronized. They were too erratic. They were used for open flash only and exposure was by testing and educated guess. Bulbs became available on the U.S. market in 1930. Earlier in the UK. They weren't reliable enough in speed to start using synchronizers until the late '30s. The synchronizer came about through the experiments of the photographers of the day and they were also responsible for the improvements to the bulbs. |
I've just been doing a bit of googling, and you are right about the speeds changing in 1960 or so. It seems that manufacturers eliminated a "safety factor" of a stop or so when the standard was revised. Interesting! |
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Les
Joined: 09 May 2001
Posts: 2682
Location: Detroit, MI
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| Posted: Tue Dec 09, 2008 4:35 am Post subject: |
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It seems even Kodak didn't completely believe in those box Brownies and Duaflexes afterall!
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"In order to invent, you need a good imagination and a lot of junk" Thomas Edison |
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robcruickshank
Joined: 25 Feb 2008
Posts: 19
Location: toronto, canada
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| Posted: Tue Dec 09, 2008 4:36 am Post subject: Re: Old bulb and new film |
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| mopar_guy wrote: | OK,
You can all call me crazy.
Dave |
Not me! |
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mopar_guy
Joined: 07 Aug 2008
Posts: 126
Location: Washington, the State
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| Posted: Tue Dec 09, 2008 4:54 am Post subject: |
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The boxes for my GE 22B bulbs are labeled in no particular order "Synchro-Press 22B-Class M(medium peak)-For use with daylight type color films" also listed is a guide number table labeled "Daylight film exposure index".
The packaging for the Sylvania 2B bulbs has the following markings in no particular order "No. 2B class M(medium peak)-Since the Kelvin temperature of blue Superflash approximates that of daylight (6,000 K.), filters need not be used with daylight type color films". Also listed is a guide number table for several old film types (Kodacolor, Anscocolor, etc.)
Regards,
Dave |
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