GUIDE (1)Sure, you can apply a preset or photo effect to your entire image, but why would you want to do that? There are certain instances when applying an effect globally will only hurt the image rather than make it better.

For instance, you wouldn’t want to apply a blemish removal filter found in Topaz Clean to the entire image. If you own a copy of Photoshop, there is a valuable tool you must start using now if you haven’t already. This feature is called layer masks.

In his book, The Digital Photographer’s New Guide to Photoshop Plug-Ins, author Scott Stulberg refers to layer masks as the “best kept secret in Photoshop.” By using layer masks with plugins, you are granted more control in the editing process as you can selectively apply adjustments to your image, while leaving other areas untouched.

So are you ready to have complete control in your editing workflow? Whether new or experienced with layer masks, read on for some tricks on how to use layer masking with plugins.

How to use Layer Masks

Layer mask (noun): An editable 8-bit grayscale channel that hides some or all pixels on a layer.

Learning how to use layer masks in Photoshop is fairly simple. While many plugins have their own masking and brush out capability, the flaw with these programs is that the mask does not save once you exit the program and return to your host editor. A benefit to using layer masks is that you can always come back and re-edit the mask.

1. To start, open an image in Photoshop. Here is the image I’ll be working with in this demo (an iPhone panoramic taken just outside of our Austin office): The Best Kept Secret in Photoshop: Layer Masks2. Next, duplicate the background layer by going to Layer → Duplicate Layer (shortcut Ctrl/Cmd + J).The Best Kept Secret in Photoshop: Layer Masks3. Now that you’ve duplicated the layer, apply some sort of effect to the background copy layer. For this demo, I applied the Dramatic effect in Topaz Adjust to spice up the landscape, however I do not like what’s happened to the sky (the stitching of the panoramic has become more evident, most apparent in the middle of the image): The Best Kept Secret in Photoshop: Layer Masks4. Press OK to apply the effect, returning the image back to Photoshop. With your background copy layer selected, go to Layer-> Layer Mask. You will see two options here: Reveal All and Hide All. These two options let you paint in or paint out the filter’s effect with Photoshop’s brush tool. The Best Kept Secret in Photoshop: Layer Masks

  • By clicking Reveal All, you’ll get a white mask in your layers panel. White areas in a mask permit pixels to be seen.

The Best Kept Secret in Photoshop: Layer Masks

  • By clicking Hide All, you’ll get a black mask. Black areas hide pixels.

The Best Kept Secret in Photoshop: Layer Masks

  • To invert the selection, turning the black mask to white and vice versa, press Cmd/Ctrl + I.

6. For this demo, I will start with a black mask, and then use the brush tool to brush in the effect. Before brushing in, you’ll need to make sure that your foreground color swatch is white.

The Best Kept Secret in Photoshop: Layer Masks

  • The color swatches will be located at the bottom of your toolbar. The default colors should be black and white…press Ctrl/Cmd + D to reset them.
  • The color in front represents the foreground color, while the color behind it represents the background color.
  • To toggle back in forth between the two, press the X key.

7. Next, select the brush tool in your toolbar (shortcut key: B). Should another tool be selected, right click (or Ctrl + click) to expand the options to access the brush tool. The Best Kept Secret in Photoshop: Layer Masks 8. Now we are ready to begin painting back in the effect. But first, you may want to adjust the size of your brush ( [ , ] keys). In the top menu bar there will also be a variety of brush options too, like opacity and flow.

Tip: If you start to brush in the effect but nothing happens, make sure that the layer mask is selected. Simply click on the black (or white) mask to select it.

The Best Kept Secret in Photoshop: Layer MasksLayer mask not selected 
The Best Kept Secret in Photoshop: Layer MasksLayer mask selected

With a small brush size and reduced brush opacity, I’ll now begin painting back in the effect I had previously applied in Adjust.

The Best Kept Secret in Photoshop: Layer MasksAs you can see above, the dynamics and tonalities in the landscape have been brought out. Part of the sky was then brushed in at a very low opacity. I made sure to not brush in the effect around the areas where the panoramic stitching is most evident.

Here’s the original image again:The Best Kept Secret in Photoshop: Layer Masks

Now that you know how to use layer masks, here are some other cases where you may want to consider using this technique.

Case 1: Skin Smoothing

LeahBeforeAfterPhoto © Scott Stulberg

Certain plugins, like Topaz Clean, contain no masking or brush out capability. Knowing how to use layer masks is valuable as you wouldn’t want to apply a smooth skin filter to the entire image. Here at Topaz we often get questions about this: “Why has my entire image been flattened after using a skin smoothing preset in Clean?”.

The Best Kept Secret in Photoshop: Layer MasksAs you can see above, the skin smoothing effect has been applied globally, removing texture and detail from the model’s hair and clothing. To fix this, the solution is simple: use layer masks.

By using layer masks in Photoshop, the skin smoothing effect from Clean was first hidden with a layer mask using (Layer Mask -> Hide All) and then brushed back into the skin, with the brush set to a lower opacity. The image was then finalized with some other trickery with the available tools in Ps, including the Spot Healing Brush for blemish removal.

Leah3Case 2: Noise Removal

night_shot_without_denoisereducedScott Stulberg ran into a problem when he took the photo above. Taken with a high-ISO, a considerable amount of noise was introduced into the photograph, becoming even more amplified when enlarged.

Screen Shot 2014-08-13 at 6.29.50 PMHe was able to use DeNoise to successfully clean up the noise artifacts, however this also removed important details from the car, shed and trees where noise wasn’t as noticeable as the sky.

Screen Shot 2014-08-13 at 6.53.40 PMUsing layer masks, Stulberg was able to brush away the strong noise reduction filter he used in the lower half of the image to make it appear less intense and bring back important details.

night_shot_with_denoise reducedAfter noise reduction

Case 3: Selective Sharpening

cRobynAber2014_PimpYourSelfie_orig-resizedPhoto © Robyn Aber

While image sharpening is an applicable solution for bringing out the details and placing emphasis on the subject in focus, it is a technique you may not want to apply globally. For instance, you may want to use layer masks to sharpen eyes without sharpening the fine lines & wrinkles underneath. Other items that do not necessarily require sharpening include:

  • Skies
  • Water
  • Human skin
  • An out of focus background (bokeh)
  • Areas with evident high ISO noise
  • Areas of constant/flat color

What you do want to sharpen are the objects or elements to your image that you want to place emphasis on. Sharpening areas like the sky or out of focus objects is just going to worsen any apparent noise that’s already there. Think about it…sharpening is the opposite of noise removal – while one softens & smoothes unruly artifacts, the other sharpens the pixels that are there. So be cautious when using the two and know that you may use layer masks to selectively apply each technique where necessary.

What cases do you have for using layer masks?

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