|
By adjusting the curves, you are changing the starting point (bias) and polynomial factors, used to calculate the display brightness for that particular pixel value on the screen.
For example, your data (original pixel value) could be say 128, but the displayed value will be 255. Or, the original pixel value is 10, the displayed value is 120. For pixel value =5, display value could be 0. (please note the factor value in this example is different for different original pixel value - small original values are amplified more than large values).
The processed picture is saved without the curve polynomial in most cases (DPP can save them, though).
Things are a bit more complicated than this, because the eye response to illumination is logarithmic, not linear.. that is why you will find in literature the term "gamma" and it's associated factor.
Signal to noise ratio can't possibly be improved by curve adjustment, however it is possible to offset the noise floor so details are brought up.
The price paid for this offset is increased visibility of digitalisation noise (coarser tone resolution).
BTW, DPP and DSS operate with 12-16 bits of resolution, not 8 bit (0-255) like you mentioned.
Only the final image (in jpg format) is saved with 8-bit resolution
|