Does anyone know how to achieve this?:
>> 
I don't think you can really call it a colouring, but I wouldn't know. Maybe it's even as simple as curves, with a bit of selective colouring in it. I tried a few ways, but it hadn't come out the way I wanted, so I decided to ask for some help. If you can help, it would be very, very much appreciated. :]
(Sorry, I have no idea who made these icons.)
Another Example:
I don't think you can really call it a colouring, but I wouldn't know. Maybe it's even as simple as curves, with a bit of selective colouring in it. I tried a few ways, but it hadn't come out the way I wanted, so I decided to ask for some help. If you can help, it would be very, very much appreciated. :]
(Sorry, I have no idea who made these icons.)
Another Example: