Generally
speaking, brightness, contrast, saturation and sharpness are thought to be the
four simplest controls as they have been developed as long as the color TV was
invented in the first place. However, people often turn blind eyes to the fact
that all these four controls are related to each other. As a matter of fact,
changing any one of these four controls will influence and change the other
three. Do you have any knowledge about how they are related and how to change
the balance of brightness, contrast, saturation and sharpness by only changing
one of these three parameters? Here is some knowledge you might have desire to
know.
An
image must have the proper brightness and contrast for easy viewing. Brightness
refers to the overall lightness or darkness of the image. Most people tend to
think that brightness is the simplest control of image in concept. They believe
that changing of the bright just means the image will be brighter or darker. In
order to remove such misunderstanding, we need to distinguish brightness from
“gamma” in the first place. Actually, increasing gamma by moving a mid-tone
slider on a histogram is not the same as increasing brightness. We can’t but
admit that increasing gamma/mid tones really makes an image look brighter, but
it is non-linear because it only increases the brightness of the shadows and
mid-tones instead of influencing the highlights in the image. On the other
hand, traditional brightness equally brightens the entire image from the
shadows to the highlight in a simple way.
As a
matter of fact, if we add too much brightness, then the shadows will catch up
to the highlights as they are already as bright as they can get. As a result,
the contrast, saturation and sharpness of the image will be reduced
accordingly. Therefore, changing one of these four controls really affects the
other three. Keep in mind that you need to strike a balance; otherwise, the
image will be uncomfortable.
