What would blue be in superlative?

There isn't a superlative form of "blue" in the same way you would have "biggest" or "smallest".

"Blue" is a color, and colors are not generally used in superlative form.

Here are some ways you could phrase something related to "blue" in a superlative context:

* "The most vibrant blue": This describes the intensity of the color.

* "The bluest sky I've ever seen": This compares the shade of blue to other blues.

* "The most blue-like": This could be used in a more abstract sense to describe something that is strongly associated with the color blue.

Let me know if you have a specific context in mind, and I can help you find the best way to express it!