The sign for "blue" is made by forming the letter "b" with your right hand.
Twist/shake your hand from the elbow (the wrist doesn't bend on this sign).
Here is an example of BLUE: "Blue Bayou Restaurant"
You might also see this sign done pointing upward more than forward.
Both versions are okay. The sign isn't necesarrily forward or upward, it
is just a "B" hand held at a comfortable angle and the forearm twisted twice.
Signing note: You would NOT use the
sign "BLUE" to mean "depressed."