A quick Google search on how the eye perceives intensity-

http://www.cs.ubc.ca/~harrison/P202/PDF/05-perception-of-brightness-4up.pdf

Looks very much like how Film records intensity.

http://en.wikipedia.org/wiki/Sensitometry

And a mathematical formula to compute an "S" chaped curve:

http://en.wikipedia.org/wiki/Logistic_function

The problem: Digital Sensors and Cameras have a linear response to intensity. So what happens if you adjust the linear response of the M Monochrom to look more like what the eye would see or film would record? I'm aiming at more mid-tone separation without losing shadow and highlight details.

Well, this FORTRAN programmer just cannot resist adding this function to code that processes linear-DNG files. You could add a "gamma" type curve using "curves" in Photoshop. As far as I know, Photoshop leaves the image with the same bit-depth as read-in. Something has to get lost in the translation, ie applying a curve means some intensity values get stretched, others get thrown together.

What I am thinking: first make the Linear DNG into a 16-bit file by multiplying (left bit shift) by 4. Reset the "White" and "Black" levels in the DNG header. Applying a Gamma curve will start to fill in the missing positions of the histogram rather than lumping them together.

Make sense? Is there anyway to do this in an existing piece of Software?

http://www.cs.ubc.ca/~harrison/P202/PDF/05-perception-of-brightness-4up.pdf

Looks very much like how Film records intensity.

http://en.wikipedia.org/wiki/Sensitometry

And a mathematical formula to compute an "S" chaped curve:

http://en.wikipedia.org/wiki/Logistic_function

The problem: Digital Sensors and Cameras have a linear response to intensity. So what happens if you adjust the linear response of the M Monochrom to look more like what the eye would see or film would record? I'm aiming at more mid-tone separation without losing shadow and highlight details.

Well, this FORTRAN programmer just cannot resist adding this function to code that processes linear-DNG files. You could add a "gamma" type curve using "curves" in Photoshop. As far as I know, Photoshop leaves the image with the same bit-depth as read-in. Something has to get lost in the translation, ie applying a curve means some intensity values get stretched, others get thrown together.

What I am thinking: first make the Linear DNG into a 16-bit file by multiplying (left bit shift) by 4. Reset the "White" and "Black" levels in the DNG header. Applying a Gamma curve will start to fill in the missing positions of the histogram rather than lumping them together.

Make sense? Is there anyway to do this in an existing piece of Software?

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