How to make proper use of 'Unsharp Mask'

At first sight this tool might produce some nice sharpening-results and thus is used very often. Well it can indeed produce nice sharpening if used properly and with care.
Most people tend to make to much use of this tool.

For the sake of demonstration we will be using the following image. It provides a nice contrast and is slightly unsharp.

Instead of applying the effect once we will be using it three times. So please create three duplicates of the base layer. Make the top two layers invisible and apply 'Unsharp Mask' to the second layer from bottom:

Don't be scared about the rather hight value of the 'Amount' slider. We will be reducing this otherwise later.

No let's proceed with the next layer. We apply the same effect just with some reduced Radius:

The top Layer should get the same effect with only a radius of at most 2 pixels. But this massively depends on your overall image-size.

The last step is to blend all layers into the original by settings their 'Opacity' to about 30% each. But you should fiddle around a bit with these settings until you somehow found a good mixture. CG is much about trial'n'error while learning.


This was just one short entry to somehow push you into a new direction. What you should alwas remember that one effect alone will never ever produce any good result. It is always the combination and the choice of effects that matters. Not so much intensity or complexity of one single effect. Complexity is achieved by adding several single and simple effect and the interaction of theses effects is what blows your mind .

Awesomeness of THE CHANNEL MIXER

The Channel Mixer function is a really nifty tool when it comes to changing the mood in an image, roughly changing the color situation in the image or applying some really freaky color-mess in a pic.
The third one is rather easy. So I will leave this to your own experiments.
The mentioned change of color can be done with one or two layers. So we take an image like:

We duplicate this layer and fire upon the top layer the Channel-Mixer(Colors - Components - Channel Mixer) dialogue and apply following settings:

Now we are done after setting the top layers mode to "Hard/Soft Light". Both modes yield good but very different results:

As you might have noticed the Channel Mixer also produces good results in converting an image to greyscale since it offers more space for tweaking.

Now we want to exploit the region of color modification guided by our friend the Channel Mixer.
We will be using the same pic as above. Make a fresh start and duplicate the layer again, and fire up the Channel-Mixer again with following settings and output:

You should be very careful with the sliders. They work as follows: in the red channel the red-slider is at 100 by default because the red channel is filled with 100% - guess what - yes - red. but with the channel-mixer you are now able to mix other colors into the red-channel. so if you ADD some blue in the red-channel you should substract some in the the others.
This will somehow shift the amount of blue to other regions in the picture and thus creating another mood. This is very powerfull since you can combine it with layer-masks and layer-modes to achieve more complicated effects. But this is up to you. Another hint might be to size up the Channel-Mixers windows since the preview also scales up in comparison to most of the other effects in Gimp