Histogram Repair

[EchoingWhisper]

A Photoshop plugin to repair posterized histogramsHow could I get the same effect using just Photoshop without filters?

 

[Garbz]

You can not create what isn't there. How does a histogram repair tool know how to replace a missing value? How does it know a value is missing at all?

Posterisation is often handled by adding noise, or dithering. Unless there's a gradient then posterisation is often not field relevant. If there is a gradient a blur or press of the add noise button may help, but the best solution to this problem is prevention. Work in 16bit.