Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 69,933   Posts: 1,522,235   Online: 1033
      
Results 1 to 9 of 9
  1. #1

    Join Date
    Nov 2003
    Posts
    5,231
    Images
    9

    color of light question

    What color will a red or blue or green led light be on color film? Will they photograpgh as these colors or would I have to filter for each one to keep their color?
    Technological society has succeeded in multiplying the opportunities for pleasure, but it has great difficulty in generating joy. Pope Paul VI

    So, I think the "greats" were true to their visions, once their visions no longer sucked. Ralph Barker 12/2004

  2. #2

    Join Date
    Nov 2004
    Location
    Italia
    Shooter
    Multi Format
    Posts
    4,680
    Don't know about LEDs but

    Blue will look yellow on the negative.

    Or do you mean the print? Or something lit by the LEDs?

  3. #3

    Join Date
    Dec 2002
    Shooter
    Large Format
    Posts
    6,242
    It depends on the type of film...if transparency the colors will be the color of the LEDs and if negative film they will not be...filtering should not be necessary.

  4. #4

    Join Date
    Nov 2003
    Posts
    5,231
    Images
    9
    I mean in the final print.

    Donald, Why would they not be the same with color neg film?
    Technological society has succeeded in multiplying the opportunities for pleasure, but it has great difficulty in generating joy. Pope Paul VI

    So, I think the "greats" were true to their visions, once their visions no longer sucked. Ralph Barker 12/2004

  5. #5
    htmlguru4242's Avatar
    Join Date
    Aug 2005
    Location
    Sandy Hook, CT
    Shooter
    Multi Format
    Posts
    973
    I believe that Donald is talking about the colors appearing on the physical strip of film. With color negative film, the colors would be inverted on the strip of film, as it is negative film. On slide film, the colors would be correct.


    The LEDs, if photographed, will be of the correct color (obviously accounting for the slight inaccuracies that occur with all color films) on the print. Whatever color you see will be close to what will be on the print.

  6. #6

    Join Date
    Nov 2003
    Posts
    5,231
    Images
    9
    Cool, thanks guys, found a neat idea and want to try it out.
    Technological society has succeeded in multiplying the opportunities for pleasure, but it has great difficulty in generating joy. Pope Paul VI

    So, I think the "greats" were true to their visions, once their visions no longer sucked. Ralph Barker 12/2004

  7. #7

    Join Date
    Aug 2005
    Location
    Los Alamos, NM
    Shooter
    Multi Format
    Posts
    2,043
    Green, yellow, orange, and red LEDs are narrow line width sources. They should reproduce fairly accurately on color film, although the brightness may not be the same as you see with your eye. You can make a fair guess by looking at the published sensitvity curves for the film. Blue, violet, and "true green" LEDs have braoder spectra. They will still probably look OK, but you could get some funnies. White LEDs are usually a combination of a blue LED and a yellow phosphor. The emitted light is really quite blue. Most produce a decent white source light for daylight film, but some show maked dropouts in certain colors.

  8. #8
    127
    127 is offline
    127's Avatar
    Join Date
    Feb 2004
    Location
    uk
    Shooter
    127 Format
    Posts
    581
    You'd need to combite the spectral response of each film layer with the spectra of the LED. I'm not at all convinced that narrow band emitters will record at all well...

    An led which emits only light in one of the films spectral bands (ie affects only one layer) cannot be recorded accuratly - the film only records the intensity FOR THE LAYER.

    There's no way to differentiate between two different LEDS that trigger the same band to the same extent. If a green led only triggers the green layer, then there's no way to know WHICH green it was, just that it's green and how bright. It'll be green on film, but not the same green. Any LED that's completly within the green band would look exactly the same on film.

    Typically we get away with it as real world sources have broad spectra, and trigger all three layers to some degree.

    Ian

  9. #9
    htmlguru4242's Avatar
    Join Date
    Aug 2005
    Location
    Sandy Hook, CT
    Shooter
    Multi Format
    Posts
    973
    Mark, what exactly are you trying to do here with the LEDs?



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin