CentralNotice From Wikipedia, the free encyclopedia Jump to: navigation , search This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed. (February 2008) ( Learn how and when to remove this template message ) The term black fax refers to a prank fax transmission, consisting of one or more pages entirely filled with a uniform black tone. The sender's intention is generally to use up as much of the recipient's fax ink, toner , or thermal paper as possible, thus costing the recipient money and/or denying the recipient use of their own machine (this is similar to computer-based denial of service attacks). This is made easier because the fax transmission protocols compress the solid black image very well, so a very short fax call can produc...