X-Git-Url: https://git.cinelerra-gg.org/git/?p=goodguy%2Fcin-manual-latex.git;a=blobdiff_plain;f=parts%2FWindows.tex;h=1d618ac5e047743efda9d93743b3938a6c880db6;hp=760a69601ed98a7a7e6b384bd7f2aed42368dbf4;hb=6da2f169fab398a313d2710a4040393ef491705b;hpb=d5251682fdccb408356205f2d05da4273988cdba;ds=sidebyside

diff --git a/parts/Windows.tex b/parts/Windows.tex
index 760a696..1d618ac 100644
--- a/parts/Windows.tex
+++ b/parts/Windows.tex
@@ -1100,6 +1100,8 @@ The compositing pipeline graph has a masking stage (figure~\ref{fig:temporary-02
 
 The Mask popup menu can be overwhelming upon first encounter.  However, if you follow the next
 few steps you can create a single simple mask without having to understand every possible parameter.
+Be sure you are working in a Format that includes the Alpha channel, YUVA or RGBA, because you need
+to have transparency for masking to show or will end up with only a black area.
 \begin{enumerate}
     \item To define a mask, in the Compositor window click on the \textit{Edit mask} icon to get the popup Mask menu.  If the menu does not come up, click on the \textit{Show tool info}.
     \item  On the video, LMB click on the place where you want to start a mask.