The Midtone point represents the Gamma setting for your particular screen. On the histogram, the Shadow and Highlight scales are divided into 255 units.
Therefore, all pixels in the original that are darker than the current shadow point are now completely black in the enhanced image. Conversely, all pixels in the original that are brighter than the current highlight point are now completely white in the processed image.
Setting the highlight point to 200 renders all pixels greater than or equal to 200, on the original, completely white in the processed image. Similarly setting the Shadow point to 200 renders all points less than or equal to 200, on the original, completely black in the enhanced image. Photographers often refer to these effects as
The Midtone is a relative measure of the gamma of your monitor. The scale for Midtone ranges from 0 to 255. The gamma curve is on a geometric series. This means that at a value of 255 it tends to infinity.
The Midtone is bound by the Shadow and Highlight terms and cannot exceed them at any time. So, if the Highlight is set to 255 and the Shadow is set to 0, a gamma of 1 is equal to a Midtone of 128. Similarly, if the Shadow is set at 200 (lower boundary) and the Highlight is set at 220 (upper boundary), a gamma of 1 is equal to a Midtone of 210.
