[kubuntu] Do you know an app with good colour adjustment utilities?

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http://ubuntuforums.org – Hi, First of all: if you are reading this the chances are you have struggled with colour adjustment at some point. Please tell me about it even if you are not certain it would help me. I've been using a lot of ink trying to get the colours of a picture the way I would want them to be. There is a HUGE difference between the colours displayed on the screen and the colours of the printed page. In paint I have in "Balance": Brightness, Contrast and Gamma. This can be applied to all channels or to one of the channels: Red, Green, Blue. There is also "Hue, Saturation, Value&qu (Hardware)