There is a myth that people only dream in black and white. If you have not dreamed in color or cannot remember doing so it simply means just that. It does not mean that others do not!When I am asked, it always reminds me of an argument between my mother and eldest brother. She was arguing that cats can only see in black and white but he was having none of it. Voices got raised and my sister came in to see what the commotion was. "Oh, Jimmy was here in his last life as a cat", smirked my mother with victory in her eyes. Quick as a flash Jimmy replied, "And mother was here as a color blind one!"
You already know what some colors mean
The interpretation of colors in dreams comes from their interpretation in the human aura. Instinctively we know the meaning of some colors. Have you ever been red with anger or green with envy? Have you been down with the blues? Ever called anyone a yellow belly? Do you have a friend who sees things as black and white? Have you described things you are not clear on as a grey area? A bride wears white as a symbol of purity (I'm ignoring its older association with wealth!) and we give red roses to our lover.
Our association with colors is also precise when it comes to their meaning in dreams.
You'll find detailed descriptions of the meaning of colors in your dreams at
color-in-dreams