Interactive Luminosity Masks


The Interactive Luminosity Mask (ILM) panel is a novel Adobe Photoshop extension for creating luminosity in a more efficient and user friendly way. ILM allows the interactive creation of custom luminosity masks/selections with instantaneous visual feedback. The main advantage of ILM over the traditional luminosity mask approach (i.e., running actions which create a fixed number of possible luminosity mask channels) are:

  • ILM only creates the masks you need and not a huge set of masks which will consume a lot of extra memory
  • ILM allows very fine control over the luminosity/saturation mask range, unlike many luminosity mask actions which only provide masks which roughly half their selection at each step
  • LM provides an instant feedback of the mask on screen
  • ILM's way of computing zone masks is more precise and flexible than common approaches of computing zone masks based in the intersection of highlight and shadow luminosity masks with themselves.
  • ILM automatically provides direct support for the most common uses for luminosity mask (e.g., selections, channels, curve layer, etc)
  • ILM does not use selections to create the masks which allows ILM to create true 16bit masks (in the case of 16bit images)

If you like this panel you should checkout my new Interactive Blender Panel too. 


The Interactive Luminosity Mask extension panel is offered free of charge and may be used for personal or commercial work a like. The redistribution of the panel without my written permission is prohibited.


If you like to support ILM and my work, you can buy me some cookies here: 


Go to the Adobe Exchange page and press the 'Free' button and Adobe CC should do the rest.


After you successfully installed the panel you can open it via Window > Extensions > Interactive Luminosity Masks. When the panel window opens it will show the menu dialog:

The top 2 buttons allow you to create luminosity and saturation masks. The last 3 buttons provide links to external resources. After selecting either the highlight or saturation masks the next screen will appear:



The first 3 button let you create highlight, midtone or shadow masks. The next button allows you to create zone masks. If you selected Saturation masks in the previous menu this screen will offer thee identical functionality for creating masks based on saturation instead of luminosity.

Highlight, Midtone and Shadow Masks

Assuming you pressed the Highlights button the panel will create a few helper layers showing in the layer stack, show a preview of the luminosity masks in the main view and switch to the highlight dialog:


On the top there is a graphical depiction of which highlight range is currently selected. This dialog has a slider on the top which allows you to control the amount of highlights the luminosity mask will select. Moving the slider to the left will select less highlights and moving the slider to right will select more highlights. Under the slider there are 4 button which allow you to fine tune the selection by incrementally adjusting the slider.

At the bottom of the dialog you will find the various buttons to take action upon the chosen luminosity mask:

  • Selection: Creates a selection based on the luminosity mask.
  • Channel: Stores the luminosity mask in a new channel.
  • Curves Layer: Creates a new curves adjustment layer with its layer mask set to the luminosity mask.
  • Levels Layer: Creates a new levels adjustment layer with its layer mask set to the luminosity mask.
  • Hue/Saturation Layer: Creates a new hue/saturation adjustment layer with its layer mask set to the luminosity mask.
  • Cancel: Do nothing and return to normal Photoshop.

All actions which create a new layer/channel will show a dialog, asking for a name of the layer/channel. The midtone and shadow dialogs work exactly the same way only differing in the fact that they create luminosity masks for midtones and shadows.

Zone Masks

The zone mask are a tribute to Ansel Adams zone system. Unlike Adam's zone system the interactive zone mask allow for a contiguous selection of the luminosity range instead of just allowing 11 zones. After clicking on the 'Zone Mask' button the following dialog will appear:


On top of the this dialog there is a 'Select Zone from Color' button. Clicking this button will show the color picker dialog and allows the selection of a luminosity range by selecting a color directly from the picture. The 'Zone' slider below selects the center value of the luminosity zone. The buttons below allow a more fine-grade selection of the luminosity zone value. The 'Feather' sliders adjusts the width of the zone (i.e., how many of the neighboring luminosity values are included in the selection) for the shadow/highlight parts independently. The buttons at the end of the dialog act exactly the same way as described in Highlight, Midtone and Shadow Masks.