On Facebook recently one of my friends asked the question 'What would a mirror look like if it did not reflect light?'. To this my immediate response was along the lines of: > An object which reflects no light but absorbs all light will be the darkest and most opaque object imaginable > An object which reflects no light but transmits all light will be completely and utterly invisible But then I got thinking... what would an object look like which reflects no light, absorbs some light and transmits the rest? Based on the conclusions above common sense tells me that the object could be described as translucent grey/black although I am far from convinced by this conclusion. So here are my questions: was my initial response correct? What would an object which reflects no light, absorbs some light and transmits the rest look like? Does such an object exist?