Colors are one of the first vocabulary sets most learners pick up because they are concrete, they come up constantly, and half of them follow one easy pattern. If you know the manual alphabet, you already have the handshape for blue, green, yellow, and purple. Everything else fits in a short list.
The shaken-letter colors
Blue, Green, Yellow, and Purple are each the first letter of the English word, held in front of you and shaken with a small twist of the wrist. B shakes for blue. G shakes for green. Y shakes for yellow. P shakes for purple.
The trick is to keep each handshape clean. At speed, a loose B and a loose G can look alike. Make the letter, then shake it; do not shake while you are still forming the letter.
Colors on the face
Red brushes the index finger down over the lips. Pink does the same brush with a P handshape. Black draws an index finger across the forehead, like an eyebrow. White starts with an open hand on the chest and pulls away as the fingers close.
Red and pink are a matched pair, so learn them together: index finger for red, P for pink, same motion.
The rest of the set
Orange is a squeezing fist at the chin, the same sign as the fruit; the clip for the fruit is at Orange (fruit). Brown draws a B down the cheek. Gray passes two open hands through each other, fingers interlacing.
Gold touches the ear and shakes a Y hand, the same motion as the sign for California. Silver touches the ear and shakes an S. Bright opens both hands upward from the center, like light spreading.
Using colors in a sentence
In ASL, the color usually comes after the noun it describes, or the noun is set up first and then described. "A red car" is CAR RED. "My shirt is blue" is MY SHIRT BLUE. There is no "is."
Intensity lives in your face and hands. A big, slow, wide-eyed RED is "very red." A small, quick RED is just red.
Practice
Look around the room and name five colors you can see, signing each one. Then do it with the object first: WALL WHITE, SHIRT BLUE, CUP RED. Five minutes of that and the set is yours.
Next: Family for the next matched set, or Descriptions for more adjectives to pair with colors.