A vignette is a gradual darkening or lightening of the edges of an image, typically used to draw attention to the center of the image or to create a sense of depth.

The purpose of using a vignette in photography is to draw attention to the center of the image. This can be done by darkening the edges of the image, which makes the center of the image appear brighter and more prominent.

There are three main types of vignettes: radial vignettes, linear vignettes, and elliptical vignettes. Radial vignettes are the most common type and are created by darkening the edges of the image in a circular pattern. Linear vignettes are created by darkening the edges of the image in a straight line, and elliptical vignettes are created by darkening the edges of the image in an elliptical shape.

The easiest way to create a vignette in Photoshop is to use the Vignette filter. This filter allows you to control the amount of darkening or lightening, the shape of the vignette, and the midpoint of the vignette.

Fading in photography is a gradual decrease in the intensity of light or color. This can be used to create a sense of depth, to draw attention to a particular element of the image, or to create a more ethereal or dreamy look.

There are a number of ways to create a fading effect in photography, including using a neutral density filter, using a graduated neutral density filter, using a long exposure, or using a software program.

The main difference between a vignette and a fade is that a vignette is a gradual darkening or lightening of the edges of an image, while a fade is a gradual decrease in the intensity of light or color.

Vignettes can be used for a variety of purposes in photography, including drawing attention to the center of the image, creating a sense of depth, adding a decorative element to the image, and hiding unwanted elements in the image.

Fades can be used for a variety of purposes in photography, including creating a sense of depth, drawing attention to a particular element of the image, and creating a more ethereal or dreamy look.

Some common mistakes to avoid when using vignettes and fades in photography include using a vignette that is too strong, using a fade that is too abrupt, and using a vignette or fade that is not appropriate for the image.

You can practice using vignettes and fades in photography by experimenting with different settings in your camera, using a software program to create vignettes and fades, and looking at examples of vignettes and fades in other photographs.

Vignettes and fades can be used in a variety of creative ways in photography, including creating a sense of mystery or intrigue, adding a vintage or retro look to an image, and creating a more abstract or artistic image.

Square is not a type of vignette. Vignettes are typically radial, linear, or elliptical in shape.

Using a polarizing filter is not a way to create a fade in photography. Polarizing filters are used to reduce glare and reflections.

All of the above are common mistakes to avoid when using vignettes in photography.