Everything Papercraft - Masking

Masking, in paper craft, is a technique used to either produce a negative image or to protect an area of your project from the application of further mediums such as paint or ink. Paper crafters are able to purchase premade masks in a variety of shapes. They are usually made of plastic or strong card and have a tacky adhesive that holds them in place during use. The mask is semi-adhered to the paper surface and then ink or paint is applied directly over the top. The areas of paper not covered by the mask will pick up the colour, while the paper beneath the mask does not, thus leaving a negative image on the page once the mask is lifted. There are several other ways to mask an image, including the application of a liquid mask or applying a layer of paper or tape over part of a stamp before adding the ink, and then removing the layer before stamping.

Here are some useful tutorials:

Masking

Masking on a Stamp