Would using black background and light foreground reduce the LCD power consumption? Or actually increases it?
Se o painel for um OLED, sim, isso reduziria consideravelmente o consumo de energia. Se for um painel TFT, exibir cores pretas / escuras não reduziria o consumo de energia - source :
One of the big variables with OLED displays is battery life—an OLED's power consumption varies greatly with the gray level of the image it's displaying. Bright images with low gray levels consume much more power than darker images with higher gray levels, as shown by the slide below, which came from a May 2008 OLED presentation.
Though it's not apparent from the slide because of the selection of sample patterns, power draw varies pretty linearly with mean gray levels, and the range is fairly wide. This inconsistency may have some implications for interface design.
Se você tiver um painel TFT, a única maneira de reduzir o consumo de energia do monitor é reduzir o brilho da luz de fundo, o contraste e talvez desativar as otimizações no monitor (se houver).