Brightness affects both dark and bright areas of the screen.
Contrast adjust the ratio of the brightest areas of the screen versus the darkest areas of the screen.
"The contrast ratio is defined as the ratio of the luminance of the brightest color (white) to that of the darkest color (black) that the system is capable of producing" (Copy pasted from Wikipedia)
Do look at backlight settings and make sure it is turned on in either the average or maximum state.
But to fix this issue you need to increase the brightness due to the outside brightness washing out all of the colors.
After that you need to decrease the contrast until the picture looks acceptable.
Without proper color calibration tools your going to have to do this...