Lynn from LynnBaileyPrintmaker has shared her lovely video demonstrating collagraph! Collagraphy is a 'printmaking process in which materials are applied to a rigid substrate (such as paperboard or wood).'
Follow this link to watch the actual video: http://vimeo.com/50941703
Here is also an example of one of Lynn's finished pieces using this technique - Beautiful!: http://www.etsy.com/listing/97914056/hedgerow-flowers-spring-collograph-mono