Involves selective coloring
Using photoshop CS (but it should works with all the photoshop versions)

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Rules
- don't claim it as your own
- credit isn't necessary but if someone ask you for this coloring you have to point to this tutorial
- comments are really appreciated
- if you have any questions feel free to ask
- do you like what you see? Friend me!

Let's start!

=> Remember that every picture is different so play always with the setting to fit your icon!

Step 1
Take your base and do whatever you want: crop it, sharpen it, screen or multiplay if it needs


Step 2
Layers > New Adjustment Layer > Selective Coloring, set at 35% opacity
REDS: - 100 | 0 | +53 | 0
YELLOWS: - 27 | 0 | +26 | 0
CYAN: 0 | 0 | +50 | 0


Step 3
Layers > New Adjustment Layer > Selective Coloring, set at 50% opacity
REDS: -71 | 0 | +42 | 0
YELLOWS: -68 | 0 | -16 | 0
NEUTRALS: +36 | -16 | -30 | 0


Step 4
Layers > New Adjustment Layer > Curves, set on RGB channel at 25% opacity
point 1 input: 75 output: 69
point 2 input: 123 output: 139


Step 5
Layers > New Adjustment Layer > Levels, set at 50% opacity
RGB channel (input) 10 | 1,14 | 245


Step 6
Layers > New Adjustment Layer > Selective Coloring, set at 70%
REDS: -50 | 0 | +30 | 0
CYANS: 0 | 0 | 0 | +40
BLUES: 0 | 0 | 0 | +100


Step 7
Layers > New Adjustment Layer > Levels
RGB channel (input) 10 | 1,20 | 255


Step 8
Layers > New Adjustment Layer > Brightness/Contrast
brightness +6


At this point you can stop here or you can follow the last two steps!

Step 9
I add a solid colour layer because the picture was to reddish for my taste
Layers > New > Level
Fill with a light blue (I used #c5f7f9) ans set this layer to Colour Burn at 30% (but it really depends on your picture and on your personal taste)

Step 10
Time for give colours to the white background!
I added this made by noisettee, I rotated it to fit the icon and I set this level to Linear Burn at 60%
Then I erased the parts which covered Alexis's face, I duplicated this level and set to Colour Burn at 20% to add more contrast

And we have finished!
Final Result


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