Most of the images that I make are shot in the studio on a 16-shot digital back, where I have a GreTag Macbeth Color Checker in the scene to use as a reference. My practice is to increase the lighting until I achieve 230-235 on the white square, knowing that I can print that value (white with some detail).
Now the question, I sometimes have a bit of space to the right of the first observable highlight data in the Tif files' histogram, with a LEVELs adjustment layer and holding down the OPTION/ALT key while dragging the highlight slider to the left until the screen shows the first pixels light up. The meaning that I take from this observation is that there are no RGB data to the right of that point.
Is that a correct understanding?
Jerry Reed