Science has the answers. Or, anyway, science has a fascinating look at why this particular question cannot be satisfactorily answered.
Also, being 16 weeks pregnant, this is relevant to my interests. I look forward to the subjective debate in the comments.
On the left is a picture of me with my bike, taken by my friend Laura Kling. On the right is the same image, as it would be seen by a person with protanopia — a relatively common (as in, still very rare) form of color blindness that affects the ability to see green, yellow, and red colors.
The Color Blindness Simulator will allow you to do this with your own photos.