I saw the dress photo as blue & black. If you're a female, even if we perceived the exact same color, you might might not have said 'blue & black'. That's because women have a larger color vocabulary than men, and you might have elaborated on exactly which blue and which black.
This blog is about a fun/unscientific comparison of the color names men and women use. If you do a Google search for 'men women color names' and look at the images, you will get several matches showing various visualizations of a spectrum of colors, showing that women have a different name for each one, whereas men tend to lump them together into groups.
I used Pixeur to determine the hex rgb code for each color in their spectrum, and entered the info into a SAS dataset, along with what men and women call it. I then used a data step to loop through each line of data, and annotate a bubble of that color, along with the text names, onto a SAS gslide. Here's a snapshot of my graph, and if you click on it you can see the full-size interactive version that let's you hover your mouse over each color to see the rgb hex code.
Have you found this gender difference in color naming to be true? If so, what do you think is the root cause?