Why will an eraser rub out writing from a graphite pencil but not from a coloured pencil ?

Question

Why will an eraser rub out writing from a graphite pencil but not from a coloured pencil ?

Answer 1

The eraser is misnamed.  In fact it removes a layer of paper that contains the graphite.  Crayon is a wax and the action of an eraser only serves to spread the wax over a wider area and therefore appears not to work.

Also graphite is to some extent absorbed by rubber compound...wax is not.

Answer 2

What the others said is absolutely correct.  The important thing to realize is that colored pencils are made from wax that is infused with pigment.  It is extremely difficult to remove the wax and pigment from paper, in fact, it really is impossible to get it all.

However, there is a way that you can remove the majority of the wax and pigment, allowing you to go back over the area with a different color.  It is a mechanical eraser.

You can get a battery operated one at most office or art supply stores for around $10 or so.  When used with colored pencil you do not want to attempt to erase large areas!  However, it is ideal for small areas or lines.  I have actually used mine to remove colored pencil to create highlighted areas.  

If you need any more information about the eraser, let me know.

Answer 3

Yet with coloured pencil, the lead/wax is highly pigmented, so it somewhat stains the paper, so an eraser is unable to remove the stains.