Nope--litho films "see" red and orange as black--graphic arts labs and newspapers use orange Amberlith sheets to mask areas on the full page negatives that they will later drop in another image and use red tape (looks like regular scotch tape but red in color) or red opaque compounds to mask out small pin holes in their negatives. Put a red filter on your lens and get zero exposure just like you had the lens cap on!! You might try a yellow filter which passes red and green light or a green filter the "Ortho" films respond to both blue and green light--exposure compensation would be pretty high. The "line" films (check you data sheets) are ofter sensitive to only blue light.
Good luck PS: ortho works great in pinhole cameras! darkroommike >Rick, > >Is it even worth trying to use an orange or red filter to try to correcr >some of the blue sensitivity? > >Gene > >Rick Dingus wrote: > > > > Many years ago I built a 16" X 20 " field camera and experimented with >using > > 16 " X 20" generic ortho film from Freestyle instead of regular >panchromatic > > film because it was cheap and because it looked a lot like 19th Century >film > > when processed for continuous tone. (Blues are rendered lighter in >tone, > > reds dark, and it is so slow that you end up with time exposures even in > > bright sunlight.) The film manufacturers all refused to advise me, >saying > > that high contrast film was not intended for continuous tone and they > > wouldn't guarantee the results. But by trial and error, and months of > > experimentation, I found a method that worked well. > > > > Testing the development and exposure by printing and not by eyeballing >is > > essential because the drastic dilution changes the color of the film to >a > > muddy brown--what looks to the eye like a very flat negative actually >prints > > on photo paper with much more contrast because of the change in color, >which > > is similar to the color of a safelight. The film speed is also >extremely > > slow, about ISO 1.5 instead of 6, because you need shadow detail if >you're > > trying to avoid high contrast. > > > > Even development was another problem with such large negatives. I >settled > > on using a Dev-Tec color print processing tube with constant rolling > > agitation, reversing direction every 30 sec. Keep in mind "expose for >the > > shadows, develop for the highlights" and print on photo paper to >evaluate > > exposure and contrast (minimum exposure time for maximum black of the >clear > > edges of the film). Increased development increases contrast, decreased > > development softens contrast. Development is affected by: > > 1. Time (the longer the time the more the development) > > 2. Dilution (the stronger the concentration the faster the development) > > 3. Agitation (the more agitation the faster the development) > > 4. Temperature (the warmer the developer, the faster the development) > > > > I ended up with something like 1/4 oz HC110 concentrate (straight from >the > > original bottle, not diluted into stock solution like Kodak recommends, >in > > 32 to 40 oz water at 70 degrees F for a development time of about 5 1/2 >to 6 > > 1/2 minutes. My students have achieved similar results using 35mm >Kodalith > > film, resulting in 35mm negatives that are so fine grain that they >almost > > appear to be large format. > > > > Try to keep your development time to 5 minutes or longer for even > > development. Bracket your exposures and development to find the best >kind > > of detail and contrast. Its slow and unconventional, but it does work >and > > can create a beautifully delicate tonal range that takes full advantage >of > > all the blacks, whites and middle tones afforded by your paper if tested >and > > handled carefully. > > > > Good luck. > > > > Best, > > > > Rick Dingus > > > > > From: Gene Johnson <[EMAIL PROTECTED]> > > > Organization: @Home Network > > > Reply-To: [EMAIL PROTECTED] > > > Date: Mon, 15 Oct 2001 11:00:57 -0700 > > > To: cameramakers <[EMAIL PROTECTED]> > > > Subject: [Cameramakers] industrial films > > > > > > Hello Cameramakers, > > > > > > I was wondering if anyone has had experience with using any of the >Kodak > > > or other large industrial films like precision line film or >reproducing > > > film in their large format cameras. I see this stuff as surplus from > > > time to time, and was curious about it. I know these are generally > > > ortho films, and I have no experience with that. Will I be able to > > > develop it with ordinary developers? Also, I just bought a huge roll >of > > > Aerial reproducing film, Kodak SO-192 for just about nothing. It's 5" > > > rollfilm and I've also just bought a 5" rollfilm back to use it with. > > > Since there are no available tanks to develop it in, I'm hoping I can > > > modify a multi-roll Jobo tank to allow me to develop 6 feet or so at a > > > time. I also hope I can "reverse engineer" the back to see how hard it > > > would be to make approximate copies. > > > > > > > > > Gene Johnson > > > _______________________________________________ > > > Cameramakers mailing list > > > [EMAIL PROTECTED] > > > http://rmp.opusis.com/mailman/listinfo/cameramakers > > > > _______________________________________________ > > Cameramakers mailing list > > [EMAIL PROTECTED] > > http://rmp.opusis.com/mailman/listinfo/cameramakers >_______________________________________________ >Cameramakers mailing list >[EMAIL PROTECTED] >http://rmp.opusis.com/mailman/listinfo/cameramakers _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp _______________________________________________ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
