I have never had any luck candling very dark brown or colored eggs. I still use my led flashlight to monitor aircells though . Tonight my led flashlight burned out so I grabbed my husbands flashlight out of his hunting bag. OMG! I can see blood veins and the chicks moving for the first time. Not sure if anyone else has tried this flashlight but I was truly amazed at what Im able to see. Its a Remington blood tracker using the red light led only. I can see with the dual light as well but its brightness seems to bother the chicks. They are available at walmart in the hunting area for $15. Hope this is able to help any of you that have been unable to find something that can see into dark/colored eggs. Good luck to everyone on their hatches.