@Background Pony #D779  
Of course! Spike lived in a pony culture whose language can differentiate distinct colors (and some shades too), as well as lived in a vibrant chromatic environment (though as stated in the article, language of colors is the major factor on why different cultures can or cannot distinguish different shades or different contrasts in chromatic spectrum)

@laofuzi
 
I’m car blind because I can’t tell a coupe from a sedan or a family van from an SUV. Why? because I’m totally ignorant about cars and don’t have a trained eye for it. Ember’s the same, she’s very unfamiliar with ponies, so her eyes aren’t used to their distinguishing features yet.
 
If your theory is correct then Spike probably had the same difficulty as well, but given prolonged exposure to the ponies, he developed a method for telling them apart.

I fucking love how pissed they look.

It’s a joke.

Since dragons are not used to being in a vibrant colorful environment (as they live in a habitat of dirt brown, ash black, lava red and orange), my theory is that they have limited languages describing a whole range of different shades of one specific color, but also groups distinct colors in the same category
 
See #5 in this Cracked article for human examples
 
Despite reptiles having better color vision than humans (even in dim light), dragons may not tell the difference in shades of distinct colors very well as ponies do
 
I think the reason why Ember lacks of finding distinctions in ponies is also the same reason why white people can’t tell black people apart and why black people can’t tell white people apart (also known as the cross-race effect )