Go to gregbenzphotography.com

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 you didn't always get the perfect composition or exposure. But likely, there was more to it. Your camera couldn't capture everything your eyes could see, or you didn't have the right tools to pull everything you wanted out of the photograph. Those tools aren't perfect, and that's why photography is an art, because we get to choose how to use those tools to represent the world as we see it. In the tools and tutorials below, I'll share the secrets of the luminosity masking and exposure blending techniques I use to to create my art.

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.

What you'll learn on this page:

  • What Luminosity Masks are
  • How luminosity masks can improve your images
  • How to create luminosity masks
  • How to use luminosity masks
  • How to blend exposures
  • More resources and Shortcuts

What are luminosity masks? 

The default selection and mask tools in Photoshop generally create black and white masks. In other words, pixels are either fully selected or not selected at all. But photographs are full of subtlety, and a black and white mask is sure to create images that look "Photoshopped". Luminosity masks offer a way to create subtle masks, so that the final results look natural and beautiful due to their soft transitions.

Luminosity masks are created from the luminosity of the image itself, which is a very convenient way to isolate something you wish t adjust in your image. For example, a white (blown) sky is just a highlight. Once you create a mask a mask to select the highlights, you can then darken those highlights through curves or levels (or numerous other approaches, as luminosity masks are simply a way to constrain what will be adjusted - you can use any tool you wish). And since the sky highlights gradually fade from top to bottom, so will your mask - resulting in a very soft and beautiful transition (unlike the hard and unrealistic transition you would get by trying to select the sky with a tool like the magic wand).

It's much easier to show how this works than explain it all. In this first video below, I give an overview of the basic concepts and why this approach to retouching is so powerful.`

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. Anytime you want to adjust something that's visually unique in the image (a particular midtone, highlights, shadows, etc), luminosity masks can be extremely useful. Here are a few examples:


 Landscape:

  • Manually blend multiple exposures to increase dynamic range. 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 exposures from different points in time to recreate the mood of a place. The goal here is to capture various elements of a scene that may not have occurred at the same time, or to capture all the various elements when they look their best. I often combine the beauty of a sunset shot with the city lights from a "blue hour" shot taken 30 minutes later. This lets me capture more intense lights, longer streaks in headlights, etc. And many times important lights may not turn on until the sunset has long since faded.
  • Targeted adjustments of tone. You can easily select stars and make them brighter, without bringing out noise in a night sky.
  • Targeted adjustments of midtone contrast to add more detail in key areas without blowing highlights or shadows.
  • Targeted color adjustment. Change the mood of your image by enhancing blue shadows or warm highlights.
  • If you've ever used Nik's Viveza tool, imagine putting that on steroids to select and adjust anything in the image for complete creative control. I've used luminosity masks to get rid of a blue shadow cast over purple light where the colors of the blue sky and street lights were mixed.
  • Targeted adjustments of sharpening and noise reduction. Luminosity masks make it easy to sharpen highlights/key details, or to apply noise reduction to only the shadows.
  • Targeted adjustments 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).
  • Luminosity masks are most often associated with landscape work, but they are actually useful for nearly any type of photography...


 Black and White fine art photography:

  • Precision control over tone/contrast throughout the image.
  • While paths remain a critical tool for selecting architectural subjects, luminosity masks can be both a great compliment to paths, as well as being a faster alternative to them in many situations.

 

Real Estate:

  • Exposure blending to retain exterior detail in windows.
  • Targeted color correction, including situations with unavoidable 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.


 Weddings:

  • Weddings are the ultimate pressure cooker. You're supposed to work with high contrast clothing in the worst possible mid-day light and produce stunning works of art. No matter how well you plan to find good light, you're probably going to encounter some less than perfect lighting situations. Luminosity masking can be a very helpful way to elevate these challenging images to the quality your clients expect.
  • Bring back highlight detail in the bride's dress.
  • Control contrast by dodging and burning or using curves adjustments with luminosity masks.

 

Portraits:

  • If you do family portraits, especially with young children outside, then you are probably dealing with many of the same challenges as weddings. You may have a little more flexibility, but the unpredictability of kids/weather and the need to book sessions at various times of the day may well create some lighting challenges that may need to be addressed in post-processing.
  • Dodge and burn the background to add interest or reduce distractions.
  • Easily lighten/whiten eyes and teeth.
  • Manual blending to extract more highlight color and shadow detail from a high contrast scene. A great example would be a backlit model at sunset. Simply processing the same properly exposed RAW a couple times can be a great way to bring back a lot more detail. This can produce much more beautiful and realistic results that using shadow and highlight adjustments on a single RAW exposure. With careful shooting to avoid alignment issues for a moving subject, you might even use multiple exposures.


 Sports:

  • For artistic sport portraits or high-end composites, luminosity masks can help in numerous ways as highlighted above.


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. For this reason, I probably wouldn't use luminosity masks 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.  

Using 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. There are many good uses for this approach, but the most common is for dodging and burning. You will likely need to use multiple different masks to varying degrees to dodge and burn your image. While you could do this with layers, it can be cumbersome and can make your file enormous. 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. This is of course a destructive process, but often the best choice for this stage of post-processing.

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:

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