Linear workflow: understand it!
Have you ever wondered why your GI renderings start out so dark? Well, in fact they are not so dark. The problem lies with the display device (the CRT or LCD) and that the software is not making adjustments for the gamma that the displays put on our images.
Look at this tutorial to solve definetly your darkness… ; )
/ Also Learn Corona Renderer
thanks for sharing but i want to ask that can i do this in photoshop or not?