Page 1 of 2 12 LastLast
Results 1 to 10 of 19

Thread: In Camera Tricolor separations, HOW?

  1. #1
    SF Bay Area 94303
    Join Date
    Aug 2005
    Location
    SF Bay Area
    Posts
    433

    In Camera Tricolor separations, HOW?

    Has anyone tried to make in camera color separations, scanned them and then reassembled color photos in photoshop?
    So if so:
    1) What filter set (25, 47B, 58) or (29, 47b, 61)?
    2) Did the exposure for each filter vary and by how much?
    3) What film developer combination?
    4) Same development time for all 3 separations?
    5) Is it easy to register the images in photoshop?
    6) Did it work? And yes if stuff moves between exposures you get color fringing.

    Thanks
    Kirk

  2. #2

    Re: In Camera Tricolor separations, HOW?

    you might want to look into four color seperation for press work, i did a lot back in high school, but my note book fell off the buggy on the way home.

    either your subject will have to be very still, or you will have to change filters very fast.

  3. #3

    Join Date
    Jan 2001
    Posts
    4,590

    Re: In Camera Tricolor separations, HOW?

    Kirk, I haven't done it for 50 years, but it used to be standard for making Dye Transfer prints from still life. I don't remember the details, but I do remember that each film had different exposure times, and different develoment times. It was a HORRIBLE PITA.
    Wilhelm (Sarasota)

  4. #4

    Join Date
    Dec 2001
    Location
    NJ
    Posts
    6,953

    Re: In Camera Tricolor separations, HOW?

    Kirk, if you have in mind to shoot, e.g., landscapes in b/w and end up with color prints, and read french go here http://www.galerie-photo.info/forum/ and search for trichromie. Henri Gaud has been working at it and has got interesting results, some quite good.

  5. #5
    Donald Qualls's Avatar
    Join Date
    Oct 2004
    Location
    North Carolina
    Posts
    1,092

    Re: In Camera Tricolor separations, HOW?

    If you watch eBay carefully for a while, you might see a tri-color camera go by. I've seen a couple, at least one in 5x7, even. These expose all three films at once, using neutral density along with the color filtration to even out exposure. Given the dense filtration needed, it's still possible to shoot living (if not genuinely action) subjects at reasonable shutter speeds by using ISO 320-400 film.

    For *viewing*, it almost doesn't matter what filters you use, as long as the final images are viewed with the same filters (Autochrome, essentially tricolor on a single film or plate, used violet, green, and orange, at least early on). For *printing*, the same is true except that it's very helpful to have the filters match fairly well to the sensitivity curves of the emulsion layers in the print material, or to complement the ink or dye colors for print or transfer.
    If a contact print at arm's length is too small to see, you need a bigger camera. :D

  6. #6

    Join Date
    May 2002
    Posts
    27

    Re: In Camera Tricolor separations, HOW?

    Quote Originally Posted by Kirk Fry View Post
    1) What filter set (25, 47B, 58) or (29, 47b, 61)?
    2) Did the exposure for each filter vary and by how much?
    4) Same development time for all 3 separations?
    5) Is it easy to register the images in photoshop?
    1) When I did direct screen seperations from slides in an enlarger for process printing, I used the 25/47B/58 filters. These broader cut filters were used because the overlap of colors allowed for corrections to compensate for impure color press inks. Since you're reassembling the image in the computer before you go to a printing device with hopefully cleaner color inks, I would say to use a narrow cut filter combo. With the broad cut filters, you'll end up with off color and muddy reds, greens, and blues.

    2) There will be a filter factor for the exposure. If the film manufacturer doesn't have a starting point on the data sheet or reply to an inquiry, you'll have to experiment.

    4) Just for giggles, I experimented with indirect (continuous tone) seperations. I tried Plus X, Tri X, and T Max 100 films. There were different development times with Plus X and Tri X, but T Max 100 had the same developing time for each color. (Don't be like me my first time- snip a different corner of each neg when you load them to tell which color is which. )

    5) Does PS have a registration function? I got the hobby version with my scanner and haven't gone through all of its capabilities yet. When we first went digital at work, we used a Leaf Scan. It did re-registration if it was off vertically or horizontally. I never had one that was crooked so don't know if it worked for those.

    The tricolor camera Mr. Qualls mentions is your best bet if you plan to do a lot of this. Unless your camera is rock solid, just changing film holders will play havoc with registration if the rear standard moves even slightly.
    Last edited by Hal Hardy; 19-Nov-2006 at 10:43.

  7. #7

    Re: In Camera Tricolor separations, HOW?

    Hello! If you google astrophotography, you'll see that folks were doing some amazing tricolor work with Tech Pan up to just a few years ago. The filters varied a bit as t what people wanted to do. Tech Pan had a high red sensitivity, so that had to be considered into the system as well. Best regards.

    Mike

  8. #8
    Tracy Storer's Avatar
    Join Date
    Nov 2001
    Location
    Oakland CA
    Posts
    862

    Re: In Camera Tricolor separations, HOW?

    It's covered in David Scopick "THE GUM BICHROMATE BOOK" and In Richard Farber "HISTORIC PHOTOGRAPHIC PROCESSES" and I'm sure, many others. It's do-able, but pains-taking. A lot depends on what printing process you're using how fussy you want to be. Here's a link to a couple examples of mine:
    http://www.tracystorer.com/tri_color_work.html
    Tracy Storer
    Mammoth Camera Company tm
    www.mammothcamera.com

  9. #9

    Join Date
    Dec 2005
    Location
    Southern California
    Posts
    2,721

    Re: In Camera Tricolor separations, HOW?

    Quote Originally Posted by Kirk Fry View Post
    Has anyone tried to make in camera color separations, scanned them and then reassembled color photos in photoshop?
    So if so:
    1) What filter set (25, 47B, 58) or (29, 47b, 61)?
    2) Did the exposure for each filter vary and by how much?
    3) What film developer combination?
    4) Same development time for all 3 separations?
    5) Is it easy to register the images in photoshop?
    6) Did it work? And yes if stuff moves between exposures you get color fringing.

    Thanks
    Kirk
    Hi Kirk,

    That's the exact same idea I've been thinking about for some time, but never quite got to try. So, your post finally made me do a very primitive but quick test with the equipment I have on hand.

    Going down your list of questions:

    1) Cokin red, green and 80A - nowhere near the ideal combination, but that's what I have.
    2) For each exposure, I took an incident reading through the filter, incident light.
    3) 320 TX in D76, 1:1, tray
    4) Yes, same time, same agitation, one-shot chemicals.
    5) Yes, it is, relatively speaking. There is a little trick to it, though, which I will describe later.
    6) Sort of. The scanner and the "technique" I used with it was too imprecise for this to really matter.

    Attachment 1166

    Since I don't have a large format film scanner, I scanned all three negatives in a reflective mode, with white paper behind them. It took a little experimentation and the results are, of course, unusable for any kind of even semi-serious work, but again, that's what I have on hand and it served the purpose of a quick experiment.

    To register two layers in Photoshop, change the blending mode of the upper layer to "Difference". This will create an effect similar to positive-negative. Simply move the upper layer until you accomplish the minimal difference. Finally, turn the blending mode back to "Normal" and you are done.

    Once all three layers are in precise register, copy the "red" layer into the red channel, the "green" layer into the green channel and the "blue" one into the blue channel. Delete the layers and use the Channel Mixer and curves to adjust the color balance and saturation.

    For comparison, here is the regular image taken with a digicam:

    Attachment 1167

    Regards,

    Marko
    Last edited by Marko; 6-Nov-2008 at 09:37.

  10. #10

    Join Date
    Sep 2003
    Location
    South Carolina
    Posts
    5,206

    Re: In Camera Tricolor separations, HOW?

    Quote Originally Posted by Kirk Fry View Post
    Has anyone tried to make in camera color separations, scanned them and then reassembled color photos in photoshop?
    So if so:
    1) What filter set (25, 47B, 58) or (29, 47b, 61)?
    2) Did the exposure for each filter vary and by how much?
    3) What film developer combination?
    4) Same development time for all 3 separations?
    5) Is it easy to register the images in photoshop?
    6) Did it work? And yes if stuff moves between exposures you get color fringing.

    Thanks
    Kirk
    Back in the 1980s I made quite a number tri-color carbon prints, some from in-camera separations, others from separations made from 5X7 Ektachromes transparencies. For in-camera separations you want to use the 25, 47 and 58 set, for separations from slides the 29, 47b and 61. The difference between the two sets is that the band width for the second is not as wide as for the first.

    I used primarily Super-XX film, which has a very long straight line curve and was one of the films recommended by Kodak for separations. Exposure for the Red and Green record were about the same, but much less for the Blue. Development was different for each of the records to produce a balanced set. I used Kodak DK-50 to develop the separations. In experimenting with a couple of other films results varied a lot, so you will obvioulsy have to experiment a lot to get this right.

    It has crossed my mind to assemble some of the separation negative sets in Photoshop and while I have not done it, I don't think it would be particulary difficult to do so.

    I also have a 5X7 Devin tri-color camera but one of the pellicle mirrors is torn and would have to be replaced, at $250, to put it in use. I plan to do so at some point in the future as I would like to do a project with it.

    Sandy King

Similar Threads

  1. CARBON INFINITY CAMERA 5"X4"
    By EUROMODEL in forum Cameras & Camera Accessories
    Replies: 22
    Last Post: 17-Oct-2017, 07:23
  2. Psuedo helical focussing - possible?
    By bglick in forum Lenses & Lens Accessories
    Replies: 78
    Last Post: 19-Jan-2012, 02:30
  3. Am I boring? (deciding 8x10 or larger)
    By Janko Belaj in forum Cameras & Camera Accessories
    Replies: 19
    Last Post: 19-Jul-2005, 13:40
  4. Camera delivery and service stories :an alternative view
    By bob moulton in forum Darkroom: Film, Processing & Printing
    Replies: 6
    Last Post: 6-May-2002, 12:15

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •