Recently, I found my new love in the art of white on black, used a white charcoal on a black paper, and firstly used a grid system with a mechanical pencil (2B lead). Then used drew it from the reference image I acquired online by placing it on my laptop. Yes! Almost all my drawings were created by studying the image on either my smartphone or my laptop. Do download these awesome applications, either gimp 2.8 or photofiltre7. They help immensely in gridding and filtre effects.