How to rate CDU for outdoor shots?

Discussion in 'Large Format' started by alpshiker, Apr 21, 2003.

  1. I have a box of Fuji duplicating CDU II which I want to try for outdoor low contrast shots. How much should I rate it and do I
    need to filter for preliminary testing?
  2. Okay, I found some answers on the ISO rating as I searched the database: Between 7 and 11 ISO according to different sources. Pfew! that's slow. Balance should be daylight if I remember correctly.
  3. It's figure out the speed based on your set-up, but it's optimized for a one second exposure, if I remember right. I shoot it at work and it's been awhile since I did this--but the speed sorta floats between 6-12 ISO. You set the shutter at 1 second, set up your filter pack and do a test by bracketing through apertures and film speeds. I came up with ISO 6 for our setup--we use a Nikon F3 and a 55 Micro Nikkor with a Chromapro. My base exposure is 1 sec at f11.5. This stays constant once you get it all set-up... The starting filter pack will be listed on the film can and the side of the box as well. The final pack will be different for you most likely, and depends on your E6 as well. I can't help you much on shooting it as a camera film--you can get a spec sheet from Fuji though, for reciprocity etc. hope this helps?
  4. Ouch! Adding a two stops conversion filter will not help. I thought it was daylight or maybe they had another kind for flash light earlier. Never mind, got this pack at outdated price so it's not too much of a loss if I can't make something of it. Will try anyway. Thanks for the tips!
  5. well, you can use it on dupers with a flash, you just have to adjust your filter pack...
  6. Using tungsten film in daylight you only lose 2/3 of a stop with an

    DK, can you say how much, if at all you have to re-test each time
    you get a new batch? Can you just re-zero your filter pack using
    the numbers on the box, or do you have to run the exposure
    index and colour balance tests another time?

    I am about to try Edupe for landscape use. I reckon I can live
    with small colour and E.I. changes from batch to batch, but
    would like to avoid too much test shooting.
  7. That's right, it's the Blue 80A that takes two stops. It should be manageable.
  8. The Matterhorn isn't going anywhere :)

    Do you have any specific images in mind to use the film for? For
    me, it's not insignificant that duping films are the cheapest way
    into LF colour, but their low contrast, good reciprocity, wide,
    accurate tonal range and the ease of proofing make them
    attractive as pseudo-negative films; at least in theory.
  9. The Matterhorn isn't going anywhere, you are right. I was thinking of using it inside the forest at this time of the year. Any other film would not cope too well with the high contrast that's in there. I have had other opportunities where a low contrast film would have been welcome. But if it's too much hassle with filtering (my box says additional 25Y and 5C are required!) and long exposures, i'm not sure it is worth the effort. You are right in your idea to use it as a semi-negative. I thought it would allow editing by zones in Photoshop, just as a print is made by zones under the enlarger. But first let's see what sort of results it yelds!

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