.
.
Water
soluble pencil:
Very
flexible, it can draw a variety of tones from soft grey to dark black.
You
can also dilute the pencil, to achieve a watered down colour - more
or less tense.
.
.
Sanguine:
They
exist in different tones: soft and hard, very difficult to erase.
They
give a great result on coloured paper and enhance the white in white
paper.