Digital Light & Color

…Local Contrast Enhancement of Luminance Medium Detail [mid-frequencies]…

The starting image…

...1) Click on the starting image and Extract its Luminance channel…
...2) High Pass Blur the extracted Luminance channel with settings: Amount=100; Threshold=100; Radius=10; click OK…
...3) USM the resulting 2) image version with settings: Amount=100; Radius=2; Threshold=3; click OK…
...4) OK a Brightness Curve smooth curve=[0,15], [30,30], [50,50], [100,75] with Amount=100 to the resulting 3) image version…

...5) Click on the starting image and open Composite-Hard Light where Input=starting image at Amount=67 or preference and Overlay=the resulting 4) image at Amount=100; click OK… …creating the Medium Detail Luminance Local Contrast Enhancement image…
The Step 5) resulting image…

...6) Continue with preferred “Creative and/or “Output” sharpening techniques... ...and final tone/color adjustments...

Considerations:
...1) Starting image should be approximately 3456x2304 pixels; near full range with no shadow and/or highlight clipping; near preference tone and color; contains very little luma and/or chroma noise; has "Capture" sharpening applied with no "Creative" and/or "Output" sharpening…
...2) If the largest starting image dimension is significantly different, then linearly ratio the suggested Radius of Steps 2) and 3)…
...3) The suggested Brightness Curve provides a bias towards the dark half of an edge contrast and lowers the applied dark half to light half edge gradients, reducing the potential for unwanted light half edge gradient halos… …You can modify this curve to preference light half/dark half edge gradients from a 50% tone of an edge by changing/adding/removing control points about the [50,50] control point…
...4) Steps 1) through 4) could be saved with the resulting 4) image version as a 'snippet' workflow…

References…
…1) “Guide to Image Sharpening”: http://www.cambridgeincolour.com/tutori ... pening.htm
…2) “PhotoShop’s “Freaky Detail” and PWP4 or later”: http://www.dl-c.com/board/viewtopic.php ... =high+pass

Have fun…

If of interest, a larger finalized IMG_0991 [Lower Yellowstone River Falls and Canyon] may be viewed here: http://www.ncplus.net/~birchbay/13/IMAG ... _13_96.htm

…den…

Add’l Comments…

Considerations: …4) should read: Steps 2) through 4) could be saved with the resulting 4) image version as a 'snippet' workflow… …as there is no Extract workflow widget.

If one wanted, a non-Luminance LCE for medium image details could be done that would be a near equivalent to Steps 1) through 4) that use available PWP6-7 widgets… …however, a luma/chroma High Pass Blur image tends to produce complementary color casts to an edge contrast gradient under certain conditions that would likely go unnoticed in realistic photo images… …if of further interest, I could list the needed steps for this approach which are not significantly different than those already suggested… …however, the Luminance LCE method is my preference.

A further illustration… …a 1:1 300x575 pixel image area crop of the right side of the falls, before and after:


…den…

Nice rendering, thx Den.

Update: …Use an interactive Mask Tool-Brightness Curve to essentially duplicate the suggested Step …4) Brightness Curve of the resulting Step …3) image…

As noted in Consideration …3) this curve profiles the dark to light edge contrast gradients. An interactive mask will allow with a None or Undo of the Mask Tool to change the dark to light biasing while monitoring Preview during the Step …5) Composite-Hard Light blend transformation to further your preferences to be image specific.

An updated workflow:…
...1) Click on the starting image and Extract its Luminance channel…
...2) High Pass Blur the extracted Luminance channel with settings: Amount=100; Threshold=100; Radius=10; click OK…
...3) USM the resulting 2) image version with settings: Amount=100; Radius=2; Threshold=3; click OK…
...4) Click on the resulting 3) image version and open the Mask Tool – Brightness Curve; lower left Apply Add a Smooth curve = [0,85], [25,100], [50,100], [100,75]; and leave the Mask Tool ‘active’ on the resulting 3) image…...5) Click on the starting image and open Composite-Hard Light where Input=starting image at Amount=67 or preference and Overlay=the resulting 3) image with the …4) mask white Amount=100 and …4) mask black Amount=0; click OK… …creating the Medium Detail Luminance Local Contrast Enhancement image…
...6) Continue with preferred “Creative and/or “Output” sharpening techniques... ...and final tone/color adjustments...

Example… if the suggested Step …4) mask curve still results in objectionable white half edge halos, one could: click Mask Tool None; relocate the [100,75] control point vertically downward to [100,65]; then lower-left Apply Add the revised curve; and watch for the change to occur as Preview updates…

…perhaps with a little bit of thought you will be able to visualize the near equivalency of the suggested Mask curve when applied to a High Pass image histogram distribution to the originally suggested Brightness Curve transformation of the USM sharpened High Pass image version… …Hint: the suggested Mask curve behaves in the same manner as does the Density Masks of the HDR/Stack Images transform.

One does not need this understanding to achieve improved medium detail contrasts without objectionable white edge halos… the workflow can be surprisingly rewarding…

Have fun exploring/experimenting…

…den…