pixel rule.

So, eff'ing the pixel is a term used in a small part of the retouch community when involved in journal photography.

You'd think.

Why the eFF, would journal photo need a retoucher?

Retouchers are specialized creatures. In the photo industry, they are kind'a like-a wizard that can do magic (breast enhancements to nose jobs!), or breaking rules.

In journal photo, u cannot put an extra arm on a person's head. You cannot fake a man being slaughtered and cannot black out like really black out some parts in the photo.

So, the industry rule in digital medium goes to "don't fuckkaround wit the pixels."

You cannot alter the physical (oxymoron lol) pixel in any way, period.
Editing can go only as far to what darkroom could have done. Photo darkroom. 

Today that can mean a lot.
We have the capability to zoom to 800% and retouch pixel by pixel.
RGB channels can be edited at pixel level. This was big.
That 1 pixel that's magically green is illegal to blow out using j-tool or the stamp tool, but it can be legally adjusted manually by switching your RGB parameters.

When dealt with 40-years old photos (i.e.: Elvis portraits), this pixel rule gave new light.
Evident color noises from decade old photos were adjusted so it be nicer looking. legally.