-This effect can combine several tracks by using the Overlayer. This is a basic internal device normally used by \CGGI{} to create the dissolve transitions and for compositing the final output of every track onto the output bitmap. The Overlayer has the ability to combine one or several image layers on top of a "bottom layer". It can do this combining of images in several different (and switchable) output modes such as \textit{Normal}, \textit{Addition}, \textit{Subtract}, \textit{Multiply} (Filter), \textit{Divide}, \textit{Max} and \textit{Replace}. For a detailed list refer to the on \hyperref[cha:overlays]{Overlays} chapter -- PorterDuff.
+This effect can combine several tracks by using the Overlayer. This is a basic internal device normally used by \CGGI{} to create the dissolve transitions and for compositing the final output of every track onto the output bitmap. The Overlayer has the ability to combine one or several image layers on top of a "bottom layer". It can do this combining of images in several different (and switchable) output modes such as \textit{Normal}, \textit{Addition}, \textit{Subtract}, \textit{Multiply} (Filter), \textit{Divide}, \textit{Max} and \textit{Replace}. For a detailed list and some differences in output expectations, refer to the \hyperref[cha:overlays]{Overlays} chapter -- PorterDuff.