lose their luster when flattened onscreen . 
(ROOT (S (VP (VB lose) (NP (PRP$ their) (NN luster)) (SBAR (WHADVP (WRB when)) (S (VP (VBN flattened) (ADVP (RB onscreen)))))) (. .)))
(ROOT (S (VP (VB ) (NP (PRP$ ) (NN )) (SBAR (WHADVP (WRB )) (S (VP (VBN ) (ADVP (RB )))))) (. )))