First of all, sorry for my English
Yesterday I decided to play minecraft with mods and after installing forge I realized that this happened to me, after destroy any block is me generates an effect of dark or in some cases transparency, enclose them a link to a video, fml-client corresponding -latest.log and I get at your service if you need something more
fml-client-latest.log
[embed=425,349]<iframe width="560" height="315" src="https://www.youtube.com/embed/TSHlRvXk8IA" frameborder="0" allowfullscreen></iframe>[/embed]
edit
when I add mods is not black, it is transparent