Coloured experiments

I've been told to try and experiment with colour in my drawings. It's possible the colour might add something to my work. My first attempt was creating lines with colour, the colour being the same colour of the face that the line hits. I wasn't entirely pleased with this. There's something about this drawing which doesn't have the same effect as my previous work.

Coloured lines
Coloured pencil on tracing paper
A4
2014

 This was another colour experimentation. Instead doing the same pencil line technique. but adding block colours to certain areas instead. I did prefer this outcome to my last drawing. But I'm still not entirely happy. The block colours make the face much more evident, thus making the lines almost unnecessary. I feel like this takes away from the ambiguity of the work.
 

Blocked colours
Pencil and coloured pencil on tracing paper
A4
2014