Pornography might be seen as essentially about visual images, but what do these mean if you are blind or visually impaired?
Playboy magazine used to have an edition with Braille text, but the pictures would have meant nothing to a blind person.
Lisa Murphy has spotted what she thinks is a gap in the market and produced a book called Tactile Mind.
The BBC's Claire Bolderson spoke to Lisa Murphy and Geoffrey Long, who has been blind since birth, about whether a visual medium translates.
First broadcast 13 April 2010