Flower color accuracy problems

Discussion in 'Digital Photography' started by Chris Malcolm, Aug 27, 2012.

  1. I've been struggling with my camera's tendency to get flower colours
    wrong where blue purple and magenta are concerned (Sony A550). Not in
    any consistent way. Sometimes blues come out purple, sometimes purples
    come out blue. It's partly that auto white balance gets it wrong when
    the flower bloom fills the image. Using a gray card to set white
    balance improves things. It's partly intense colours getting
    overexposed -- reducing exposure helps.

    So by way of experiment I've been photographing flowers in the garden,
    processing and printing them, and then taking the print out to the
    garden to compare it with the flower. I was stunned to discover that
    my latest careful methodology had produced a blue print of a very
    obviously pink Morning Glory bloom.

    But wait a minute! I was sure I remembered the flower being blue!
    Could it be changes in UV radiation?

    It turns out that some Morning Glory flowers change from blue to pink
    during the course of a day. And back again. Hm...

    --
    Chris Malcolm
     
    Chris Malcolm, Aug 27, 2012
    #1
    1. Advertising

  2. Chris Malcolm

    Peter Irwin Guest

    Chris Malcolm <> wrote:
    >
    > But wait a minute! I was sure I remembered the flower being blue!
    > Could it be changes in UV radiation?


    That would seem very likely to me. One way to check would be to use
    an effective UV filter. If you have a Kodak 2A gel or a Tiffen 2A
    filter one would almost certainly fix the problem if it is the UV
    content that is causing the problem. (These filters have a slight
    yellow colour to them, but are known to be completely effective
    against UV. The fact that you can not tell a good UV filter from
    an ineffective one by looking can be a problem because some things
    sold as UV filters nowadays are sold for "protection" and the makers
    do not expect the customer to care whether they filter out UV or not.)

    Peter.
    --
     
    Peter Irwin, Aug 27, 2012
    #2
    1. Advertising

  3. Chris Malcolm

    Martin Brown Guest

    On 27/08/2012 19:30, Chris Malcolm wrote:

    > I've been struggling with my camera's tendency to get flower colours
    > wrong where blue purple and magenta are concerned (Sony A550). Not in
    > any consistent way. Sometimes blues come out purple, sometimes purples
    > come out blue. It's partly that auto white balance gets it wrong when
    > the flower bloom fills the image. Using a gray card to set white
    > balance improves things. It's partly intense colours getting
    > overexposed -- reducing exposure helps.
    >
    > So by way of experiment I've been photographing flowers in the garden,
    > processing and printing them, and then taking the print out to the
    > garden to compare it with the flower. I was stunned to discover that
    > my latest careful methodology had produced a blue print of a very
    > obviously pink Morning Glory bloom.
    >
    > But wait a minute! I was sure I remembered the flower being blue!
    > Could it be changes in UV radiation?
    >
    > It turns out that some Morning Glory flowers change from blue to pink
    > during the course of a day. And back again. Hm...


    It is a side effect of getting flesh tones exactly right. They
    deliberately bury all the residual errors in the line of purples.

    http://en.wikipedia.org/wiki/Line_of_purples

    You have to be unlucky about the choice of plant but some do really mess
    up slide film - much less so on digital CCD imaging.

    --
    Regards,
    Martin Brown
     
    Martin Brown, Aug 27, 2012
    #3
  4. On 8/27/2012 2:30 PM, Chris Malcolm wrote:
    > I've been struggling with my camera's tendency to get flower colours
    > wrong where blue purple and magenta are concerned (Sony A550). Not in
    > any consistent way. Sometimes blues come out purple, sometimes purples
    > come out blue. It's partly that auto white balance gets it wrong when
    > the flower bloom fills the image. Using a gray card to set white
    > balance improves things. It's partly intense colours getting
    > overexposed -- reducing exposure helps.
    >
    > So by way of experiment I've been photographing flowers in the garden,
    > processing and printing them, and then taking the print out to the
    > garden to compare it with the flower. I was stunned to discover that
    > my latest careful methodology had produced a blue print of a very
    > obviously pink Morning Glory bloom.
    >
    > But wait a minute! I was sure I remembered the flower being blue!
    > Could it be changes in UV radiation?
    >
    > It turns out that some Morning Glory flowers change from blue to pink
    > during the course of a day. And back again. Hm...
    >

    But some flowers are notorious for photographing pink because of UV
    while appearing blue to the eye; wild gentians of Switzerland are a
    spectacular example.

    --
    Jim Silverton (Potomac, MD)

    Extraneous "not" in Reply To.
     
    James Silverton, Aug 27, 2012
    #4
  5. Chris Malcolm

    Robert Coe Guest

    On Mon, 27 Aug 2012 19:36:21 +0000 (UTC), Peter Irwin <> wrote:
    : Chris Malcolm <> wrote:
    : >
    : > But wait a minute! I was sure I remembered the flower being blue!
    : > Could it be changes in UV radiation?
    :
    : That would seem very likely to me. One way to check would be to use
    : an effective UV filter. If you have a Kodak 2A gel or a Tiffen 2A
    : filter one would almost certainly fix the problem if it is the UV
    : content that is causing the problem. (These filters have a slight
    : yellow colour to them, but are known to be completely effective
    : against UV. The fact that you can not tell a good UV filter from
    : an ineffective one by looking can be a problem because some things
    : sold as UV filters nowadays are sold for "protection" and the makers
    : do not expect the customer to care whether they filter out UV or not.)

    I'd expect flaws in the glass to be a greater problem with cheap filters than
    failure to block ultraviolet. Most cheap glass doesn't pass ultraviolet well.
    Two examples: Hospitals and nursing homes buy (or at least did the last I
    knew) special UV-passing glass for their sunrooms. And photochromic sunglasses
    don't work well in automobiles because the windows filter out most of the UV,
    and it's UV that makes the glasses darken.

    Bob
     
    Robert Coe, Aug 29, 2012
    #5
    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. Matthew Halfant

    Dimage Xt viewfinder accuracy?

    Matthew Halfant, Aug 17, 2003, in forum: Digital Photography
    Replies:
    2
    Views:
    348
    Pat_M.
    Aug 19, 2003
  2. Peter Wakeman

    Nikon 5700 flower picture problems

    Peter Wakeman, May 1, 2004, in forum: Digital Photography
    Replies:
    8
    Views:
    790
    misifus
    May 3, 2004
  3. Replies:
    4
    Views:
    509
  4. Accuracy of Dell desktop ship date?

    , Dec 8, 2005, in forum: Computer Information
    Replies:
    3
    Views:
    446
    Hank Sniadoch
    Dec 9, 2005
  5. Charles

    Flower and Polarizer and Color Temp Correction

    Charles, Jun 3, 2007, in forum: Digital Photography
    Replies:
    3
    Views:
    403
    Asle Bjerva
    Jun 4, 2007
Loading...

Share This Page