WB - from Kelvin to RGB

Discussion in 'Digital Photography' started by Radek D, Jul 27, 2006.

  1. Radek D

    Radek D Guest

    Hello !
    Anybody know function how can translate
    WB Color Temperature in Kelvin to RGB pixels values
    for exemple 3000 K = (+4 R) & (-5 G) & (0 B)
     
    Radek D, Jul 27, 2006
    #1
    1. Advertising

  2. Radek D

    kctan Guest

    you confuse WB with RGB

    "Radek D" <> wrote in message
    news:eaam2k$4et$...
    > Hello !
    > Anybody know function how can translate WB Color Temperature in Kelvin to
    > RGB pixels values for exemple 3000 K = (+4 R) & (-5 G) & (0 B)
     
    kctan, Jul 27, 2006
    #2
    1. Advertising

  3. Radek D

    acl Guest

    kctan wrote:
    > you confuse WB with RGB
    >


    How is white balancing achieved? By multiplying the each of the R, G
    and B channels by a different multiplier.
     
    acl, Jul 27, 2006
    #3
  4. Radek D

    acl Guest

    Radek D wrote:
    > Hello !
    > Anybody know function how can translate
    > WB Color Temperature in Kelvin to RGB pixels values
    > for exemple 3000 K = (+4 R) & (-5 G) & (0 B)



    1) It is a multiplier, ie each channel gets multiplied by a number
    2) Even if the raw converter assumed a black body spectral distribution
    for the source (ie only the temperature must be specified), we would
    also need to know the exact spectral response of the R, G and B filters
    for the specific camera under discussion. This may or may not be
    standardised between different cameras/sensors; I don't know.

    You can find all the answers you ever wanted by reading the source code
    of David Coffin's dcraw at
    http://www.cybercom.net/~dcoffin/dcraw/

    Sorry, but reading C code (even my own) gives me headaches, so I never
    read dcraw.c and therefore don't know.
     
    acl, Jul 27, 2006
    #4
  5. "acl" <> wrote in message
    news:...
    SNIP
    > How is white balancing achieved? By multiplying the each of the R, G
    > and B channels by a different multiplier.


    In linear gamma space, yes.

    Bart
     
    Bart van der Wolf, Jul 28, 2006
    #5
  6. "Radek D" <> wrote in message
    news:eaam2k$4et$...
    > Hello !
    > Anybody know function how can translate WB Color Temperature in
    > Kelvin to RGB pixels values for exemple 3000 K = (+4 R) & (-5 G) &
    > (0 B)


    Possibly more than you catered for, but nevertheless:
    <http://www.brucelindbloom.com/Eqn_XYZ_to_T.html>

    Bart
     
    Bart van der Wolf, Jul 28, 2006
    #6
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Bev

    RGB to CMYK

    Bev, Feb 24, 2005, in forum: Computer Support
    Replies:
    19
    Views:
    1,208
    Groleg the fetid
    Feb 24, 2005
  2. jgerard

    Color Temperture - Kelvin chart for 10D

    jgerard, Jul 10, 2003, in forum: Digital Photography
    Replies:
    1
    Views:
    3,851
    Bill Hilton
    Jul 10, 2003
  3. David Ellis

    Consequences of editing 10D jpeg in Adobe RGB color space?

    David Ellis, Oct 14, 2003, in forum: Digital Photography
    Replies:
    2
    Views:
    486
    Lionel
    Oct 16, 2003
  4. Morton

    Colorsmart RGB or Adobe RGB?

    Morton, Dec 13, 2007, in forum: Digital Photography
    Replies:
    2
    Views:
    3,910
    Morton
    Dec 14, 2007
  5. Kelvin Scale - Digital Photography

    , Aug 2, 2008, in forum: Digital Photography
    Replies:
    7
    Views:
    673
    Robert Coe
    Aug 3, 2008
Loading...

Share This Page