I encounter a problem-when I take the photos of an aeroplane flying in the sky,a black patch will appear in the sky in the photo if I use "check for dust",and each time this patch will appear in different areas,I was wondering whether there is someone who can help me solve this problem.
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Black patch in the photo when using check for dust
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Originally posted by Tang Ziheng View PostJust like this.
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The Equalize filter redistributes the brightness values of the pixels in an image so that they more evenly represent the entire range of brightness levels. When you apply this command, Photoshop Elements finds the brightest and darkest values in the composite image.
So there is something dark there - maybe a dark cloud?
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More precisely, the equalizing (and the "check for dust" function in JP is an equalizer just less progressive (different curve) than in PS or PSE) considers the darkest pixel of the image as black (RGB 0,0,0) and the brightest as white (RGB 255,255,255). The color for intermediates is function of the highest value of the pixel between R, G and B (a kind of "dark grey" like R70, G80, B70 will be green).
Equalizing filter tries to make the distribution of luminances as flat as possible.
If the original distribution in the picture is near of the total dynamic range, the corrections will be weak and the equalized image will be near the original. A strong equalization shows an unbalanced distribution of tones and à lower contrast (black is not black and white is not white).
The black patches in your photo show that these pixels are among the darkest (lowest luminance levels) in the image, that's all...
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