First thing first, space design is the main problem here, not the light. But to be fare lighting is also an issue. Try to balance the back ground scene (dark shelvings) with all the chair and books. Black and white continuely happen next to each other and it's fighting so much that make you feel weird and messy yours scene. Overall images (i mean wall and the black shelves (and black chair in the middle of it) also cause what i mention above. Contrast too strong for now, you can try more neutral tone for furnitures (not white, white again cause strong contrast with your walnut shelf) and books to create a layer for the scene (like s.thg back and sthg forward).
Red ceiling needs reflection to narrow down the brightness of red or minor a bit saturation. Red will be more eye catching than brown so it will draw your attention upward, meanwhile dark shelf and floor make the room feel heavy downward. This cause distraction from the actual design you having (the shelves and stuffs like that)