Color temperature and Black and White film

[kelly_flanigan1]

William; no problem.<BR><BR>Art summed it up that is almost never a problem the panchromatic films<BR><BR>Many times someone that is almost 80 may have alot better memory of the old times; versus the current year. My belief is that the old guy is thinking of is speed graphic; film packs; and flashbulbs; and thinking of the 2 to 1 speed difference between daylight to tungsten film speeds. With some of the prewar household 15w and 25 watt bulbs used in houses; the speed difference was about 3 to 1 ..ie tungsten was 1/3 the weston speed.<BR><BR>My prewar and early post war Kodak books cover this color temperature effect of film speed on ortho films in several paragraphs. <BR><BR>The reason old people are really concerned about lights being left on; is that electrity was very expense back then.One of my 1920 electrical books goes into a house wired with a whopping THREE 6 amp 110 volt circuits! ; the electrical code was set to a maximum of 6 amps per circuit then .(<b>that is where the magic 660 watts comes from on many older electrical sockets and items</b>) The entire 1920 house electrical design has mostly one or two 10 or 15 watt bulbs per room; with a monster 25 watter in the living room! One 660 watt circuit was for the Kitchen.. The average price for electricity then was 10 cents per kilowatt hour in the early 1920's ; today here it is about 8.5 cents....Thus electricity in 1920 was real expense compared to ones wages..<BR><BR>I have some 10 watt edison base bulbs in an ancient 8x10 contact printer...These bulbs are not all that white..; and probably have a rather low color temperature...<BR><BR>When the bulb voltage is real real low; it is so red that it can be used almost as a safelight! ..

[struan_gray]

This seems to have mutated into another 'why bother' thread. I'll

confess that the people I know who really care about this effect

with modern pictorial films are all astrophotographers who want

to get the relative brightnesses of their stars correct, or at least,

wrong by a known amount.

 

That said, I think it is significant that a red filter will make a

normally exposed scene look like you gave it N-1 development,

even if you used the correct filter factor. With Tmax and its long

straight line that's not a big deal, but with some of the more

classic s-curve films you could end up with a very different tonal

distribution to what you were aiming for. If you miss putting the

highlights on the shoulder and compress the midtones too

much, you are going to need a lot more darkroom wizardry to

make a good print than if you had simply increased development

a bit.

[kelly_flanigan1]

Struan; <BR><BR>Maybe my longterm dealing with astrophography has me fired up about this thread!<BR><BR>