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Luminosity Masks

If you're like me, you've taken a LOT of photographs that didn't quite live up to your memory of the moment. Maybe your camera couldn't capture everything your eyes could see, or you want to extract more detail in Photoshop. One of the most incredible ways to improve your images is through a technique called "luminosity masking".

When I look at the images right out of my camera, I often think "the sky was darker and more blue" or "the road in the foreground had more detail". Wouldn't it be great if there was a way to select specific pieces of the image to edit them? There is! Of course, you can manually select parts of the image with basic Photoshop masking tools like the magic wand, but those selections never really look right - they often leave telltale marks at the edges of the selections. A much more powerful approach is a relatively new technique called "luminosity masking". The idea is that you use the luminosity (brightness) or color/saturation of the image to make selections. Basically, you can tell Photoshop to make adjustments to just the bright blue pixels in the sky, put more contrast in the mid-tones of those buildings, or give those green colors more pop. In other words, luminosity masking is a way of helping Photoshop see the world the same way that you do.

Manual Exposure Blending with Luminosity Masks

What are luminosity masks? 

The default selection and mask tools in Photoshop generally create masks that either fully reveal pixels or not at all. This creates hard edges that look retouched. Luminosity masks offer a way to create subtle masks from the image itself, so that the final results look natural and beautiful due to their soft transitions. And since luminosity masks are based on the image, they are a great way to help adjust specific subjects in your image.

It's much easier to show how this works, so click play on this video for a quick demo and overview of the basic concepts.`

How can luminosity masks improve my images?

Luminosity masks can be used anywhere you would use a selection or mask. The advantage is that they offer a much higher quality mask/selection, and they can be used on almost anything. In this example image, I shot one RAW image of the Chicago city skyline at sunset, and another RAW of the city lights 30 minutes later. Using luminosity masks, I was able to blend two very different images, pull out the beautiful pink sunset I saw and create an image that recreated how I felt standing there in person. My own personal style tends towards a painterly look, and you could easily process this same scene many different ways with luminosity masks.

Exposure blending cityscape sunset with city lights

And while luminosity masks are probably most commonly associated with landscape photography, they can be useful anywhere you might use a mask or selection. Here are just a few ideas of how you could use them for various types of photography:

 Landscape:

  • Increase dynamic range by trough manual exposure blending. This is the same concept as HDR, but the results are often dramatically more beautiful and realistic. Please see below, where I dedicate a whole section of this article to this subject.
  • Blend time to recreate the mood of a place. Capture various elements of a scene when the look best. For example, you can combine a sunset image with a "blue hour" shot taken 30 minutes later. This will show the beautiful sunset, and yet allow you to light up the building and show the streaking headlights of cars.
  • Dodge and burn with much more precision and speed.
  • Reduce noise in the shadows to improve a Milky Way shot, without affecting the bright stars.
  • Remove a shadow.
  • Targeted use of filters. Often times the effect you are using will look best when selectively applied to parts of the image, rather than to the entire image. Imagine adding the type of control you get with Nik, but then applying it to any 3rd party filter (Topaz, etc).

 Black and White fine art photography:

  • Precise control over tone/contrast throughout the image.
  • Dodging and burning with an Ansel Adams type of zone system that targets the image by tonality.
  • Select objects and edges faster faster than the pen tool
Black and White - Before and After Luminosity Masks

 Real Estate:

  • Exposure blending to retain exterior detail through windows.
  • Targeted color correction to deal with mixed lighting.


 Composites:

  • Luminosity masks not only offer options to enhance various components of the image, but also give you faster and more advanced objects to select/isolate subjects. For example, it's easy to select a subject from a seamless paper backdrop with standard selection tools; but if you need to isolate a subject from a complex background, luminosity masks can be a life-saver.
  • Luminosity masks can also help create more convincing blends when there are variations in lighting, color, shadows, etc between different source images.

 

Portraits / Wedding / Sports:

  • Manage less than ideal light by diminishing distractions or restoring details. Shooting people an mean chaos and a loss of control over lighting, luminosity masks can help you get back in control of the light.
  • Control contrast by dodging and burning or using curves adjustments with luminosity masks.
  • Easily lighten/whiten eyes and teeth.
  • Use landscape techniques to create a beautiful sunset background behind your subject. 


That's a very long list, but by no means comprehensive. How do you use luminosity masks? Please leave a comment below!

When should you not use luminosity masks? This mostly comes down to a balance of quality vs speed. Luminosity masks probably aren't ideal for high volume work like budget portrait sessions or basic real-estate work. And you still need to shoot in great light for the best images (after all, luminosity masks are only created from the light you captured).

How to create luminosity masks

All that you need is a program like Adobe Photoshop. If you don't already have it, you can get Photoshop CC (and Lightroom) for only $9.99 a month. And if you'd like to know more, I wrote an article about what the benefits of CC for photographers. Considering that a Nikon D810 body without lenses already costs the same as roughly 25 years of subscriptions of Lightroom/Photoshop,I believe it's one of the most affordable investments you can make in your art. However, if you don't want to go that route, you can use pretty much any version of Photoshop to work with luminosity masks (and my free actions support most older versions).

My free panel

As you can see in the secion below on manual creation of luminosity masks, the process can get complicated quickly if you don't use some additional tools. Thankfully, there are much better options. I have created a couple of plugins for Photoshop to automate the process. I have a free luminosity masking panel for Photoshop. This plugin creates all the necessary masks in Photoshop with a single click, and can remove them just as easily when you're done. You will also receive more free luminosity masking and photography utorials to get you started.

Create luminosity masks with my free panel

Lumenzia: Select Anything with Ease!

Lumenzia is a premium luminosity masking panel for Photoshop that I created to make the process both dramatically more easy and more powerful. It additionally offers exposure blending tools, dodging and burning, custom vignettes, and much more. Click to learn more about how Lumenzia can help you make beautiful images.

Manual creation of the masks

If you'd like to learn how to create luminosity masks on your own, please see the following video. While a manual approach can be rather cumbersome, it can also be helpful to at least have a basic understanding of how to make luminosity masks on your own.  

Other Luminosity Masking Options

As luminosity masking has grown in popularity, more software packages are adding basic levels of support. As a result, the general term "luminosity masking" has become a little confusing because it can mean vastly different things.  

While luminosity masking support can be very valuable in all sorts of applications (RAW conversion, HDR processing, etc), there is no substitute for creating luminosity masks in Photoshop. Luminosity mask support in other applications may serve some very useful purposes for offering a simple way to do simple tasks in those applications. But without Photoshop, you probably will not be able to do everything you need to process your image to its full potential. 

The following features make Photoshop a critical tool for working with luminosity masks:

  • Luminosity selections. Luminosity selections are the MOST IMPORTANT tool in "luminosity masking", because they can be used to create MUCH more advanced luminosity masks that target specific areas of the image much more effectively than a general "L5" mask, for example. Probably 80% of the luminosity masks I create were painted via luminosity selections.
  • The ability to work non-destructively on COMPLEX images. This means layer masks, adjustment layers, and smart objects.
  • Custom luminosity masks. This means the ability to tweak the masks for precision based on luminosity, color, location in the image, etc. A few simple options or even a 10-zone system quickly become limiting if you cannot further customize them.
  • The ability to blend multiple images. This can be used for exposure blending (increased dynamic range), perspective blending (enhanced compositions), focal length blending (to create wide angle images that do not have tiny background subjects), etc.
  • And many more advanced capabilities only offered with Photoshop and 3rd party plugins.


If you have Photoshop, you can do all of the above (the various extension panels or actions you might use can certainly make things much easier, but everything is possible if you have Photoshop).


How to Use Luminosity Masks

Ok, enough about what the masks are, let's jump in and edit a photo. In this next video, I'll show you several ways you can use luminosity masks to improve an image. You'll learn how to use luminosity masks to burn (darken) some distracting highlights, to add some contrast to make key parts of the image pop, and to reduce saturation in a distracting light.

As you see in the video, there are many ways to use luminosity masks. In fact, you can use them anywhere you would use a mask or selection, so the applications are limitless. But you typically won't use the mask exactly as it was created (though I often use the default masks to control how sharpening and vigettes affect shadows). More often, you will want to apply the mask selectively. There are two ways to do that: by refining the mask, or by painting through a selection.

Refining Luminosity Masks

Refining a luminosity mask is a useful way to make sure that it only affects the desired areas of the image. It is also a good way to make parts of the layer more visible in areas that are only partially selected. There are three basic ways to refine a mask: paint on it (which is destructive), mask the mask (which is non-destructive, but only lets you restrict and not expand the mask), or use Photoshop's refine radius tool.

To paint on a mask, first click on the mask to make it active (or <alt/option>click it to see the mask). Once you have actvated the mask, you can paint on it with any black or white brush. You may choose to do so freehand, or you might use a selection to help paint more carefully. Making the mask more white will increase visibility of the underlying pixels, and black will make them more transparet ("white reveals and black conceals"). You can also make gray pixels in the mask become more black or white by using the dodge and burn tools in Photoshop. This is a great way to make targete refinements of the mask.

To "mask a mask", you should put your layer with the luminosity mask into a group. Do this by selecting the layer and clicking on the group icon or pressing <ctrl/cmd>-G. You can then click to add a layer mask to the group. Any black added to the group mask will make any white in the underlying layer invisible. So in this way, you can remove areas of the mask. The beauty is that you can paint white on the group mask to restore visibility of the underlying mask. However, if the underlying mask is black, there is nothing you can do on the group layer to make that area visible. So you cannot expand the mask in a non-destructive way. 

The "refine radius" tool can be very useful to deal with edge issues when blending exposures, especially at high contrast edges. This tool can be found by clicking on your mask and then going to Select/Select and Mask (or Select/Refine Mask if you are using older versions of Photoshop). This amazing tool will automatically correct most "halos" around blended edges. See the following video to learn more:

Painting through a Selection

Instead of creating masks for everything, you can also load a luminosity mask as a selection to control tools like the paintbrush. In fact, this is the most powerful way to create luminosity masks, because they can be extensively customized. 

There are many good uses for this approach, but the most common are for exposute blending or dodging and burning. For example, you could dodge and burn with layer masks, but you would need a new layer for each area you target - making the process cumbersome and your file much bigger than it needs be. Instead, you can simply <ctrl/cmd>-click on your luminosity mask load it as a selection, and then paint directly onto your gray dodge and burn layer. 

Exposure Blending

One of my favorite of luminosity masks is for manual "exposure blending". The idea is similar to HDR (high dynamic range), but the results can be much more realistic and dramatic. Exposure blending allows you to add significantly more detail in the highlights and shadows by combining multiple exposures. Or, you can even use the process on a single RAW file, as it offers powerful ways to extract all the detail. Either way, you have complete control to make stunning images from dramatic light. (If you'd like to read more about how I use both manual exposure blending and HDR, please see this post.)

This next video shows how to blend a darker exposure to restore the beautiful color and details in the highlights of this canyon. It is also possible to blend a lighter exposure into a darker exposure, but the process is more complicated. This is one of the most advanced uses of lumosity masks, so I recommend starting simple and then move on to more advanced blends as you gain experience.

A few tips for exposure blending:

  • This is one of the most advanced uses of lumosity masks, so I recommend starting simple and then move on to more advanced blends as you gain experience.
  • Try creating your masks from the normally exposed image, this typically produces the best masks (as this exposure is the closest to the desired result).
  • Don't expect to get perfect results by simply placing a luminosity mask onto a layer. You will almost always need to refine the mask to get optimal results.
  • You can also use this same process to extract more detail from a RAW file. This often produces better results than you might get using tonal sliders in your RAW conversion software. Using a single RAW eliminates alignment issues, and is often contain enough dynamic range (especally if you are using one of the latest Nikon or Sony cameras). To do blend from a single exposure, just export your RAW with a few different exposure settings (such as +/-1 stop).
  • Try using exposures 1 stop apart. Less than than typically just creates work, and more than than can make it hard to obtain natural blends.
  • You don't need to shoot 1 stop apart. I frequently shoot a bracket with -2, 0, and +2. You can easily create -1 and +1 from those (as well as -3 and +3 if desired). This will allow you to work quickly, which is helpful to reduce cloud movement or deal with a quickly setting sun.


More Resources

To help learn more, please check out the following additional resources I've created for you:

Helpful Shortcuts

There are several keyboard shortcuts which can great speed up the luminosity masking workflow. The following commands are written as they would be used on a Mac. PC users should use the <ctrl> key instead of <cmd>, and <alt>instead of <option>.

Creating Selections and Masks:

  • <cmd>-click a mask/channel to load it as a new selection. Note that <cmd>-clicking on the layer's pixel icon will load a mask based on the pixel transparency, not based on the mask.
  • <cmd> <H> to hide "marching ants"
  • <cmd> <D> to deselect (get rid of selection)
  • To convert the active selection into a mask: click "add a mask" or create a new adjustment layer


Refining Selections:

  • <cmd> <option> <shift>-click another mask or channel to intersect (ie, multiply) it with the current selection 
  • <cmd> <shift>-click another mask or channel to add it to the current selection
  •  <cmd> <option>-click another mask or channel to subtract it from the current selection


Working with Masks:

  • <option>-click layer mask to view the layer mask
  • <shift>-click layer mask to disable/enable it
  • drag-and-drop to move a mask to another layer:
  • <option>-drag-and-drop to copy mask to another layer
  • To delete a layer mask: click to select it, then click the trashcan icon