using blue flashbulbs with black & white film...?

[adam_n.1]

<p>do i need to make any exposure compensation? i was just reading a website that said using blue bulbs with b&w film necessitated making an adjustment of 2 stops. buuuut i looked around here and didn't really see anyone saying the same thing. any advice? TIA</p>

[tim_ludwig2]

<p>I used these back in my earliest days of shooting weddings in the mid sixties. I shot both color negative and black and white film and I don't recall having to make any compensation what ever. Some black and white films may have a slight increased blue sensitivity (why blue skies look nearly white without filtration), but I do not remember ever seeing any over exposure with blue bulbs unless I miscalculated the distance and simply goofed.</p>

<p>Tim</p>

[Ed_Ingold]

<p>Blue bulbs give less light than clear versions - that's why filters are called FILTERS. The effect is small, and probably well within other tolerances for B&W film. They were more expensive, which is why we didn't use them in "the day". In fact, I would dip clear bulbs in a special blue dye in order to save a little money when shooting slides.</p>

<p>Flash bulbs of any sort have to be pretty scarce these days. Aren't they considered antiques? I still have a bunch I squirreled away, in the original cartons no less.</p>

[craig_shearman1]

<p>The blue coating on flash bulbs reduces flash output compared with a clear bulb. Modern panchromatic B&W film probably doesn't much care whether the light source is daylight balanced (blue flashbulbs) or tungsten (clear). There should be a guide number on the package where you can calculate the exposure manually, or you could check with a flash meter.</p>

[marc_batters]

<p>Adam. Could you provide a link to the web article you refer. Maybe there is discussion, (or omission), as to the different classes of flash bulbs, ie: "M", "F", and "FP" class bulbs, which all had different characteristics, clear or blue. Thanx!</p>

[BrianS1664879711]

<p>Blue bulb is about one (1) stop less light than an equivelent clear bulb.</p>

[adam_n.1]

<p>thanks for all the responses. i'll see if i can find that website again. i guess maybe i'll shoot some with a 1 stop adjustment and some with none and see if it matters. when i shoot with vintage gear i like to go all the way, hah (well except for the film i suppose?)</p>

[Alan Marcus]

<p >The clear flash bulb # 5 - # 6 - # 11 - # 22 - # 25 # 31 - # 40 all outputted 3800K.</p>

<p >The blue flash bulb received a B such as # 5B - # 22B - #25B - 50B the color aim point was 6000K. We often dipped the clear bulbs in a dye called Jen-Dip. This dyed the predictive clear plastic overcoat that was factory applied to all these bulbs.</p>

<p >Now the factory applied blue dye induced a shift in the color temperate of the lamp 3800K to 6000K. This requires the acton of a Wratten Series 80 filter. In this case, the filter value of the blue dye corresponded to the Wratten 80B which has a filter factor 1/3 f/stop. </p>

[BrianS1664879711]

<p>Adam, shoot at 1 stop and 2 less. Don't bother with no correction for the blue. There definitely is a loss of light and all you'll do is waste flashbulbs, and if you are like me you are paying good money for them.</p>

<p>But why is this even a question. The blue bulbs have a GN that takes into account the blue coating. Use that, or find one of the old (1970's era) Kodak PhotoGuides and use the dial calculator they provide. In fact, that is the best thing to do. Knowing filter adjustments is good, knowing lumen output and color temperatures is interesting... but there are other factors to consider also. Have you thought about distance and shutter efficiency? That is included in the Kodak Photoguide calculator to make the computation of shutter settings a LOT easier</p>

[kelly_flanigan1]

<p>The box the blue bulbs come in have the Guide Number versus asa and reflector type. It is what you use with Pan B&W or color daylight films. It has the same Guide Number for asa 100 B&W or color daylight films.<br>

The offset for B&W was for Ortho films; so one would have to be using Verichrome in 1952 to worry about this. </p>

 

[BrianS1664879711]

<p>... and if the box is no longer with the bulbs, the Cress web site has the data for every bulb ever made.</p>

[kelly_flanigan1]

<p>eons ago Kodachrome came in a variant balanced for clear bulbs; it was Kodachrome type F.<br>

With this type F variant one needed *NO* filter with clear bulbs;<br>

but a filter for daylight and a filter for type A 3400K; and a filter for Type B 3200K .</p>

<p>That was about 50 years ago.</p>

[adam_n.1]

<p>actually now that i look at it, the cress photo site was where i read " Blue bulbs may also be used with B&W film but they are less powerful because of the blue coating so you lose approximately 2 stops of light."<br>

i guess i should have said i am using press 25Bs, but i dont have the packaging, just a large box of bulbs. i have (just a few) clear press 25s in their packaging so i was going to use the values there and adjust for the blue coating. i'm also using flashcubes, which are really AG-1B. the packaging for these doesn't have separate values for b&w or color.</p>