Change one pixel colour to another quickly

[stuart_9616]

Hi, I frequently import TIF drawings into photoshop in RGB 204, 204, 204 (grey), but need to change all pixels to 255, 255, 255 (white).

At the moment, I'm using the paint bucket to change the grey pixels to white. This is time-consuming because PS doesn't do a flood fill because of jagged edges.

Is there a way of getting PS to recognize all the grey pixels and change them to white?

[D Fosse]

From how you describe it, it sounds like you just need to lift the overall white point using Levels or Curves.

Post an example so we can see what problem you're trying to solve.

Generally, the paint bucket is impossible to control, and among experienced users considered one of the worst and most useless tools in Photoshop. 

[c.pfaffenbichler]

Could you please post screenshots with the pertinent Panels (Toolbar, Layers, Options Bar, …) visible? 

What are your  settings (like Tolerance and »Contiguous«)? 

Please post the sample image @D Fosse asked for.