copperbar

copper +‎ bar, after the "copper" (coprocessor) component of the Commodore Amiga chipset.

copperbar (plural copperbars)

1. (demoscene) An animated horizontal bar of colour that extends into the overscan area of the display.
   • 1996, WolfMan^iNSaNiTY, “Which scanline???”, in comp.sys.ibm.pc.demos (Usenet):

     There a^[sic] quite a lot of effects you can get with horz.retraces, eg a textmode copperbar (change color #0 with every scanline)

   • 1998, Paul-Jan Pauptit, “Raster trix are a problem nowadays.”, in comp.sys.ibm.pc.demos (Usenet):

     Although most cards still support screen-tweaking, you can just forget about copperbars (writing within horizontal retrace fuks up the screen BADLY) and other effex. Same goes for changing the font.

   • 2000, Lando, “looking for software”, in alt.amiga.demos (Usenet):

     There was also the (really pretty famous) RSI Demomaker that let u make up your own intros/demos from a load of stock effects (bobs, starfields, copperbars, scrollers etc).. havent been able to find that tho...