Photoshop. How does it work?


Specifically, how does photoshop crop out part of the image and fill in with what was behind it?

Example: I crop out my friend from the photo, and it fills in where he was as if it knew what was behind him.

In: Technology

It’s not actually filling in what’s behind your friend; Photoshop is actually making it up using its best guess. That content-aware fill is completely fake.

Layers. All about the layers.

It’s like a giant cookie with only some parts cut away to reveal what’s underneath

It’s using the colors and light-dark values of adjacent pixels to calculate the replacement vales for the pixels you want changed. There’s more logic underneath that, but that’s the idea.

There are a couple of ways to fix an image, but it requires a person to do it. For an example: I take a picture of a beautiful landscape.
Uh-oh, it has an unsightly powerline right through the blue sky!

There’s a tool called the blemish tool, which- when you use it on the powerline- picks up the dominant color in the small area you selected and ‘decides’ what the odd-color-out is. It replaces the grey/black pixels that represent the power line with blue pixels that represent the sky. Same with acne, or spots on clothing, etc.

There’s also the clone tool, which just takes a teeny screenshot of the area you selected. You can paste this teeny copy anywhere else. With sky and trees, people usually won’t realize that the background you corrected is just another copied part of the picture.

These are just two ways to do it, but Photoshop is a large program and there are many other ways to fix that powerline in the background!