Histogram processing guide
This guide shows simple corrections that can be made with a histogram. Unlike the tone curve, the histogram provides information on a specific image. This can used to evaluate the image and make adjustments accordingly.
The pixel distribution in the histogram shows the entire tonal range of the image is not used. There is an absence pixels in the shadows and highlights.
By moving the shadow slider to the right and the highlight slider to the left to set the black and white levels to where the pixel distribution begins, image contrast is improved.
The gamma slider can be used to change the relative distribution of the tones in the image. By moving the gamma slider to the left toward the shadows, the image becomes lighter. By moving the gamma slider in the opposite direction, the image becomes darker.
White, black, & gray-point processing
On the
Click the
With the dropper tool, click on the brightest neutral area of the image to define it as the white point. The values of the image are adjusted based on the selected point. The default level for the white point is 255 for each RGB channel.
Click the
With the dropper tool, click on the darkest neutral area of the image to define it as the black point. The values of the image are adjusted based on the selected point. The default level for the black point is 0 for each RGB channel.
Click the
With the dropper tool, click a neutral area of the image to be defined as the gray point. The area used to calibrate the gray point must be neutral. The brightness level of the area is not important, but if the area has a definite color, the color is not balanced correctly.
Click and hold the apply button to show the change on the histogram. To change the white and black point values, see the following sec- tion.
Click the reset button to cancel the processing.
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