Auto White and Black point setting in a Preset

[dmward]

Bernie,
No need to regret.
I expected someone to point out that I was over simplifying by using dynamic range as a term for the stretching.

Your point about stretching the toe and shoulder which results in flattening the mid-tones is more accurate and exactly what I am trying to accomplish.

As I've said, the objective is to have a starting point that doesn't impose algorithmic compression for the sake of a "pleasing" preview.

With film we chose the emulsion, developer and development parameters along with exposure to make a negative with the characteristic curve we wanted for printing. When then had similar options with paper and development.

What I'm experimenting with is a way to get the least "adjusted" digital file into Lightroom so I can then apply the processing I want.

It appears that using DNG Profile Editor gets me toward that objective. Having a way to get Lightroom to move the least exposed and most exposed pixels to the edges is a logical step for import. Ideally, it would be nice if Lightroom did that with the sliders at 0.

[sertsa]

As an aside Shift-double clicking works with any of the tone or white balance sliders, as well as the color sliders in the B&W panel if you do not already have B&W conversion set to auto.  I believe this is mentioned in Jeff Schewe's book.

Tim

[phl0wtography]

Having a way to get Lightroom to move the least exposed and most exposed pixels to the edges is a logical step for import.

No, it isn't.
By moving the left, and right end of your histogram to the edges all you end up with is a file with hardly any leeway for curves, and local adjustments without clipping at either end.
If you really wanted to apply "your" processing, the logical step for lightroom would be to serve you with the flattest file (in terms of contrast) possible, i.e. opening shadows, reducing highlights, moving black, and white points inside, in short pretty much doing the exact opposite of what you wanted it to do.

Shift-clicking sliders is in LR since 4 iirc, but was changed to its current suboptimal behavior with LR5.3.

[dmward]

My reason for suggesting the import setting for highlights and shadows is to eliminate the toe and shoulder curves that are generally the extremes for a characteristic tone curve. The Zone System is based on white with detail and black with detail which is generally suggested to be 245 to 250 and 10 to 15. I've also seen data for Color Checker white and black squares as 93% and 15%.

Getting the white and black point out to the extreme means that one can then fine tune following other adjustments. I also realize the one can adjust them out.

A good tone curve, in my view, is one that has a steepish mid-section to add visual pop, while having a slight highlight shoulder and a more pronounced shadow toe. As stated, I prefer to start from a linear curve without a toe or shoulder rather than from a default curve with unknown compression at the ends.