In graphics, a special color register definition that allows a background color to show through. Used in dual-playfield mode.
![[Index]](../images/index.gif)
![[Contents]](../images/toc_d.gif)
![[Help]](../images/help_d.gif)
![[Retrace]](../images/retrace_d.gif)
![[Browse <]](../images/prev.gif)
![[Browse >]](../images/next.gif)