What is image masking? How to use it in photoshop?


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Photoshop Image masking

Image masking is a process in graphics software such as Photoshop that hides some parts of an image and reveals others. It is a non-destructive image editing process. Most of the time it will allow you to tweak and tweak the mask later if necessary. Many times it is an efficient and more creative way of serving image manipulation.


Type of image mask

There are three main types of masks in Photoshop:

1. Layer Mask

Layer masks are the type of mask people generally refer to when they talk about masks in Photoshop. We can hide or show parts of the image, and we can use masks to change the opacity of parts of the image. If we change the opacity of one layer from the opacity slider in the layers panel, the opacity of the entire image changes.


With layer masks, we can change the visibility of layers. We can make any part completely invisible or partially visible. If we paint black on the mask, this part of the image will be completely transparent. This means it will make the underlying layers visible. If we paint with any grayscale color, the image will be partially transparent, depending on the gray percentage we choose for the brush. If we choose a soft brush, the edge changes will be smoother.


2. Cut off mask

Clipping masks use one layer to determine the visibility or transparency of another layer. For the clipping mask, we place a layer at the bottom of the layer we want to apply transparency to. From this bottom layer, we control the visibility of the layers above. To the uninitiated, it might seem a bit contradictory if they compare the behavior of clipping masks and layer masks. Clipping masks seem to work in reverse compared to layer masks.


In the case of a layer mask, we paint the mask with black to make the pixels of the layer invisible; but in a clipping mask, we do the opposite. If the bottom layer has some pixels in that area, then the top layer will be opaque or visible. If the bottom layer doesn’t have any pixels, the top layer’s pixels will be transparent or invisible.

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3. Alpha channel masking

Each image has different properties for cutting operations, such as removing the background. So a different approach needs to be applied. Different images require different approaches. Alpha channel masking is a somewhat complex form of masking. Both of the above masking methods are fairly simple. But when we need to mask out hair and furry areas, it becomes very difficult and time-consuming to select these areas with only brush strokes. Alpha channel occlusion techniques are easier to apply if there is sufficient contrast between the object and the background.


In short, to use this masking method, we use the channels palette and see which channel has the most contrast. If it’s the blue channel, we make a copy of that channel and apply a spirit level on it to increase the contrast enough. If desired, we can paint black on the inside of the new blue channel to make it completely black. Then we reverse it so that white becomes black & black becomes white.

Next, we duplicate that channel and paste it into the layers tab, forming a new layer. You can use the dodge and burn tools to make the edges more contrasty (make the fur/hair darker on the edges). You can even choose to apply Color Desmear from the Layer > Montage > Color Desmear menu. Sometimes you can achieve amazing results with this option. It is safe to do a duplicate of the layer before applying the color desmear process. Because it is a destructive process. This is just a brief description of alpha channel masking to give you some inspiration. Now let’s see why we really need masking.


Why do we need shadowing?

It is a non-destructive technology

Shading is a non-destructive process. We can modify or fine-tune the mask when needed. However, if we erase the unwanted areas, it will be difficult to find these areas if we need them later in the image editing process. The same is true if we cut an object or part from the path made by the image. We will not be able to easily include more adjacent regions. It’s just that if we want to hide some of the areas we cut out, it might be possible by using masking techniques. For that, it’s hard to avoid shadowing anymore, right?

Image editing


just to hide and show

As I mentioned before, the simplest use of masks is to hide and reveal parts of an image. If we mask with a very soft brush or gradient, we can give a transition effect. Sometimes, we can control the transparency of certain areas in an image, such as a very shiny sky. If we wanted, we could make a very bright area of ​​the sky darker (making the area semi-opaque) by simply painting that area with a gray brush. Of course, there are other options to achieve this, Obviously, this is a simple convenient technique that you may choose.


Modify an area of ​​an image

It’s very common that you need to modify a certain area of ​​an image. For example, you want to change the color of a model’s top. You can make a mask by making that part visible. You can then apply any kind of modification you want; such as color adjustments/corrections, brightness/contrast adjustments, exposure corrections, etc.


Remove/replace the background of translucent objects

We can use masking techniques to remove the background of translucent objects. This is useful for removing the background of glass type objects. We can apply this method if we need to replace the background with a tulle or mesh type cloth with a certain transparency.


Advantages of clipping masks

One advantage of clipping masks over layer masks is that we can make different areas visible by moving the clipped image. If we use a clipping mask, we can easily fine-tune what is visible through the mask. Otherwise, I find that a normal layer mask is sufficient for almost any masking job.


Make a collage of pictures

We can make interesting collage pictures with masking technique. The possibilities for making collage pictures are truly endless. We can make interesting effects with various photos and mask them. Use a soft brush with a gray gradient to smooth out the transition.


There are almost limitless possibilities with any Photoshop technique to embody your imagination. For this, there is indeed image masking. Sometimes you can get the same result by employing a different process/technique from Photoshop. It depends on which method you are more proficient with, or which method takes less time but produces the expected output. The choice is yours. there is no doubt that image masking is a useful, creative, effective tool.