Anonymous
Anonymous asked in Arts & HumanitiesVisual ArtsPhotography · 9 years ago

Why are my infrared photos not white on the green?

Hi,

So I bought an infrared filter and I am thinking it is not right :(

The picture comes out red which is fine, but the greens are dark or red, not white or near white which they should be. Any ideas to what I am doing wrong?

In photoshop with the temp turned down, still not white (ish)

Update:

Steve, after reading the link you sent, is the problem that the WB was in cloudy? not AWB?

3 Answers

Relevance
  • 9 years ago

    It's all about reflecting and absorbing light.

    In normal light we see red as red because that is the frequency of light that is reflected. Now when you take a infrared picture you are using light we normally don't see. To make it visible you have to change the invisible to a visible color. You are actually cheating. A source emitting or reflecting infra red light is picked up by your sensor and 'translated' to white where the rest remains dark. It has nothing to do with colors we normally see.

    Some material is good at reflecting red but not infrared. Specially plants absorb a great deal of infra red and will appear black in an infra red picture.

    It essentially is a map of (reflected) invisible light. Any value can have any color you want really.

  • B K
    Lv 7
    9 years ago

    You need to process the image properly in your image editor.

    If you are doing colour infra red one of the ways to do it is to swap the red and blue channels in an image editor like Photoshop or GIMP. - here's more on that: http://stevencastle.wordpress.com/2008/07/17/digit...

    If you are doing black and white, obviously you'll need to desaturate it.

  • Anonymous
    5 years ago

    All digital photos usually need some contrast and brightest correction. Just use the "auto contrast" or "auto level" feature on photoshop or photoshop elements (or a similar image editing software). If the "auto" is not enough then do fine tuning manually.

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