Difference between Mask and Layer in Photoshop

Key Difference: A mask "masks off" parts of a layer and hides it. In other words, certain portions can be made invisible in an image so that alterations applied to the rest of the image do not affect these portions. Layer is another integral part of graphics in Photoshop. A Photoshop file can be made up of various independent layers that lie on top of each other. The layers can be independently edited.

Mask is defined as a way through which certain things can be applied to a very specific portion of an image. Mask plays a vital role in the graphic designing. Broadly, Masks can be of two types – clipping masks and layer masks. A layer mask is applied to a layer in order to control the transparency of the layer. Controls related to layer opacity can only control the transparency of entire layer. Therefore, a mask provides you the feasibility of controlling the transparency over certain specific areas. Clipping masks are also very similar to layer masks. However, these masks define the transparency from the already used layers which are required to make them. Masks play a vital role in blending of photos. Masks assist in hiding the unwanted portions of the image without the need of direct alteration. Basically, a mask helps in protecting the area of the image from being altered like the other parts of the image.

A layer in a document can be considered as a sheet of film that is transparent and clear. Layers are also among the very integral parts of Photoshop. A Photoshop file can be made up of various independent layers that lie on top of each other. A layer can be simply understood as one image stacked on top of another. The layers can be independently edited. One can easily view the transparent areas of a layer to the layers below. A special type of layer is known as a smart object that contains one or more layers of content. One can easily transform a smart object, and therefore there is no need to directly edit the image pixels. Video layers can also be formed by adding a video to the image. After using a video clip, one can easily mask the layer or transform it. All layers, layer groups and layer effects are listed in the layer panel. This panel can be used to show and hide layers.

Comparison between Mask and Layer:

	Mask	Layer
Definition	Mask is defined as a way through which certain things can be applied to a very specific portion of an image.	A photoshop file can be made up of various independent layers that lie on top of each other. The layers can be independently edited.
Types	Layer Mask – It consists of grayscale bitmap that can be applied to the layers. Vector Mask – A vector clipping path can be used with vector mask to limit the visible parts of the layer. Quick Mask - A temporary pixel-based visualization of a selection can be provided by a Quick Mask. Adjustment Layer Mask – These masks are employed to define the image areas that are affected or not affected by individual adjustments. Clipping Mask – It allows a layer or vector mask to be applied to any layer that lies above the base in the image’s layer stack.	Background Layer – it is the default image layer Image layer – contain the pixels of the image. Active Layer – Highlighted layer in which actions are applied. Adjustment Layer – They apply an effect to the pixel containing layers beneath them. Type layer – contains text in it. Shape Layer – it contains shapes and lines. Fill Layer – Solid color fill layer fill the layer throughout with the same color.
Main applications	Blending of photos and hiding portions of images without the need of direct alteration.	Composition of multiple images, addition of text to images and addition of vector graphic shapes.