If you forgot to use a polarizer when shooting, you can easily add part of the effect back again with just a few steps in Photoshop.
Before I show you the effect, let’s take a look at the before and after look. As you can see, the effect is pretty subtle, however makes a great difference when you view the photo.
Start by duplicating the background layer of the photo you wish to use. You can do that by pressing Command + J (PC: Control + J).
Next, desaturate the image by going to Image > Adjustments > Desaturate, or by using the shortcut Shift + Command + U (PC: Shift + Control + U).
Go to Filter > Blur and apply a Gaussian Blur to the image. The radius you’d want to use varies depending on the size of the image, however for most good-sized images, a radius of 40-50 pixels is fine.
Invert the image colors by going to Image > Adjustments > Invert or by using Command + I (PC: Control + I) which is the keyboard shortcut.
Set the duplicate layer to Overlay blend mode.
Open Image > Adjustments > Leves (Command + L / Control + L) and tweak the contrast to your liking. Be careful not to overdo the effect but to keep it subtle. In this case, the image could not take much Levels adjustments.
The final image result can be seen above, showing a greatly enhanced image compared to the original one.