Local Contrast Enhancement

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jsachs
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Local Contrast Enhancement

Post by jsachs »

Recently, I have been experimenting with local contrast enhancement. This sometimes goes by other names such as Clarity (Lightroom) or Microcontrast (DXO Optics).This same effect can be achieved in PWP using the Bilinear Sharpening method within the Sharpen transformation. For details, please see the new Local Contrast Enhancement white paper located at:

http://www.dl-c.com/site/articles/xform-whites.php
Jonathan Sachs
Digital Light & Color
Marpel
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What is the make/model of your primary camera?: Nikon D810
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Re: Local Contrast Enhancement

Post by Marpel »

Jonathan,

Just finished reading the LCE article and have a couple questions.

My usual image photography/editing workflow has been - shoot raw (minus any in-camera sharpening), process raw image using Nikon proprietary software (minus any raw sharpening), transfer out of raw as 16bit TIFF, capture sharpen with Focus Magic, then off to any further local sharpening during processing of TIFF (in Photoshop or PWP) and finally sharpening for printing, if needed.

Do you have an opinion on whereabouts in this workflow your LCE would fit (or replace, I guess)? and

As with sharpening, and other actions I used to do in Photoshop, each step in the process potentially relates to and changes the amount of one or all of the other steps, which make the best combination difficult to establish. In your LCE, there seems to be the same issue with the number of sliders so, is the best way to accomplish the optimum result, to start at the top, with all the other sliders zeroed out, and work your way down, or is there a particular order in which the sliders should be adjusted (I'm presuming that the top to bottom order is the best as that's the way the sliders are set up but wanted to make sure)?

Thanks,

Marv
jsachs
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Re: Local Contrast Enhancement

Post by jsachs »

I find it works best before sharpening.

I normally turn off Auto preview and then set all the sliders at once and then turn it back on.
Jonathan Sachs
Digital Light & Color
jsachs
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Re: Local Contrast Enhancement

Post by jsachs »

As far as workflow is concerned, I usually do LCE after RAW conversion and before sharpening.
Jonathan Sachs
Digital Light & Color
Winfried
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Re: Local Contrast Enhancement

Post by Winfried »

Just a question:
With my version of PWP (7.0.18) Win-7 64-bit, the Blur Radius is limeted to 20.
I guess your are playing already with the next maintenance release :-)
or might there be some misconfiguration on my system?
Winfried
-----
migrated to Windows 10 in Nov. 2019
PWP Pro 64
CUDA not available
jsachs
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Re: Local Contrast Enhancement

Post by jsachs »

Yes, larger radii are coming.
Jonathan Sachs
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Charles2
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Re: Local Contrast Enhancement - Fuji X-Trans

Post by Charles2 »

From the paper: "The simplest way is to use the Sharpen transformation and perform Unsharp Masking with a large radius setting. The problem with this method is that, depending on the image, it can create broad halos around light subjects against a dark background or dark subjects against a light background."

True. Halos, though, seem to be less of a problem with Fuji X-Trans files. Fuji X cameras have a different color filter than the standard Bayer pattern. It is less regular.

For LCE on these files, a radius around 5 and an amount of 5 to 10 percent works well. I usually dial down the white halo slider to 50 percent, too. And perhaps crucial, I set the sliders on the histogram at the bottom of the Advanced Sharpen dialog to exclude a small slice at the left.

I do this many steps after raw conversion; am I only fooling myself?
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jsachs
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Re: Local Contrast Enhancement

Post by jsachs »

I would not expect the type of dither pattern in the sensor to have an effect on halos with large radius unsharp masking.

Here is an example:
Original/Unsharp Mask/Bilateral
Original/Unsharp Mask/Bilateral
LCE.jpg (4.76 KiB) Viewed 7607 times
Jonathan Sachs
Digital Light & Color
Bob Walker
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Re: Local Contrast Enhancement

Post by Bob Walker »

Jonathan,

Did the larger radius option in the Bilateral Sharpen transform ever get into a newer PWP release?

Thanks,
Bob
jsachs
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Re: Local Contrast Enhancement

Post by jsachs »

Unfortunately not.
Jonathan Sachs
Digital Light & Color
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