You can use any medium of your choice. There is no restriction on the use of medium. It could be regular pencils, coloured pencils, graphite pencils, charcoal, crayons, sketch pens, oil pastels, watercolours, acrylic colours, oil colours. The drawing, sketch or painting can be done on any paper - it could be the regular office stationery paper or drawing paper or any other surface suitable for drawing or painting. You can also use a canvas. If you use a canvas, please ensure that you leave a margin of 2 inches on all sides for stretching. You can submit digital art as well.