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dmstraker

'Luminosity mask' selection macros

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Following on from a previous post, I've created three sets of macros for selecting a part of an image based on five Blend Ranges 'luminosity' curves (nominally called Blacks, Shadows, Mid-tones, Highlights and Whites).

 

You can download the zip file here (the forum doesn't seem to like zip files, so I put it on my website).

 

A few points of note (more in the included .pdf file):

  • The 'Preview' set just cuts out the selection so you can see exactly what is being selected. It also lets you inspect the Blend Ranges curves.
  • The 'Select' set turns this into a selection in the image.
  • The 'Blend' set does the same for adjustments and filters.
  • Curve overlaps are deliberately symmetrical so together they should sum to 100%.
  • All sets include all contiguous combinations, such as 'Blacks+Shadows'.

 


Dave Straker

Cameras: Sony A7R2, RX100V

Computers: Win10: Chillblast Photo with i7-3770 + 16Gb RAM + Philips 40in 4K; Surface Pro 4 i5

Favourite word: Aha. For me and for others.

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Hi dmstraker - thanks for taking the time and effort to craft this.  I have tested the macros on Affinity Photo for Windows and they work great.  The instructions were very clear and I am looking forward to what you come up with for extended ranges.

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dmstraker - Would there be any benefit to using a LAB color space and applying the blend range macros to the Lightness dimension?   

 

My question comes out of the assumption that the intention of the luminosity mask is to influence just luminosity and not colors as well.   

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downloaded, thanks for making these.


Skill Level: Beginner, digital photography, digital editing, lighting.

Equipment: Consumer grade. Sony Nex5n, Nikon D5100, (16MP sony sensors)

Paid Software: Affinity Photo, Affinity Designer, Lightroom4

Free Software: NIK collection, Sony CaptureOne9, Cyberlink PhotoDirector6, Hugin, ImageJ, MS Ice, Davinci Resolve

Computer: Win10 home, CPU Skylake I7-6700, GPU Saphire HD7850 1G, Plextor SSD

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dmstraker - Would there be any benefit to using a LAB color space and applying the blend range macros to the Lightness dimension?   

 

My question comes out of the assumption that the intention of the luminosity mask is to influence just luminosity and not colors as well.   

 

These macros use Blend Ranges, which work only on RGB+Master in normal RGB mode, which I'm assuming most people will be editing in. You can't switch within Blend Ranges to LAB in the way you can in Curves.

 

But yes, if you switch the document to LAB mode you could recreate the macros to apply to the Lightness channel in Blend Ranges. I've included a pdf in the document set explaining how I created the macros, including the X-Y coordinates of all the Blend Ranges points.

 

(I did an experiment just now, switching to Document/Colour Format/LAB, tweaking Blend Ranges Lightness, then switching back to RGB -- the Blend Ranges graph was still there, but it was now in Red. Hmm. Looks like a bug?)

 

You might also be able to do something in Channels, which is the classic PS way to do luminosity masking.


Dave Straker

Cameras: Sony A7R2, RX100V

Computers: Win10: Chillblast Photo with i7-3770 + 16Gb RAM + Philips 40in 4K; Surface Pro 4 i5

Favourite word: Aha. For me and for others.

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Thanks for the feedback dmstraker.  I can see the excel sheet in your PDF of the values used.  Did you just "eyeball" them when creating the ranges?  I do not see a very accurate method of inputting the values in the graph.

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Thanks for the feedback dmstraker.  I can see the excel sheet in your PDF of the values used.  Did you just "eyeball" them when creating the ranges?  I do not see a very accurate method of inputting the values in the graph.

 

X is calculated, Y is eyeballed for half curve, then kept vertically symmetrical.

 

To input them into the graph, just fill out the text fields below (and uncheck Linear).


Dave Straker

Cameras: Sony A7R2, RX100V

Computers: Win10: Chillblast Photo with i7-3770 + 16Gb RAM + Philips 40in 4K; Surface Pro 4 i5

Favourite word: Aha. For me and for others.

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