The phrase "a sad blue" is correct and usable in written English.
It can be used to describe a feeling or mood associated with sadness, often in a poetic or artistic context.
Example: "As she looked out at the rain-soaked streets, she felt a sad blue wash over her, reflecting her inner turmoil."
Alternatives: "a melancholic blue" or "a sorrowful blue".
The cover shows you your options: are you a sad blue or a green?
The back of No. 12 is five stories of jagged bricks, exposed beams and a sad blue tarp, shredded as if by desperate animals, hanging halfheartedly across a few yards of the open building.
The emotional force of the Medici-princess boxes, where the image of Bronzino's grave infanta is repeated over and over, printed in a sad blue twilight or behind a wall of sepia glass, with children's balls and jacks laid out around her as offerings, lies in the ennoblement of the fées.
Sometimes those reminders are tender moments that can bring a sweet smile to your face and a peace & comfort to your heart, while others can have you ugly crying in a department store and leave you feeling sad and blue.
As Humvees roared and rolled over the red clay track, past the cornfields, Holt, a soft-spoken man with a sad blue-eyed smile and a gap between his front teeth, talked about America's wars.
One purchased recently held a pocket flashlight, two lollipops, two novelty key chains, some Japanese gum, a Pez dispenser, birthday candles and a single, sad blue balloon.
It's all a bit too busy, frankly, but nestled among the activity are those quiet moments: Kit Fitzgerald's lingering video close-up of a clown's sad blue eye from a colorful Coney Island mural, or the choreographer Hilary Easton's awkward tango of seduction for two tentative, unlikely lovers.
Rolfe is a tall, slouchy man with sad blue eyes and a mop of dark hair that has gone gray around the temples.
"I think there are men who will deny ever having had a period of two weeks or more where they felt sad, blue or down in the dumps," said Dr. Ellen Frank, a University of Pittsburgh psychologist.
It was a sad face, blue, with big round glasses and a mustache like a pair of bluebird wings.
Georg Hallensleben's paintings of her trip have at once a poster-paint Fauve simplicity and a Vuillard-like melancholy; his water-blue skies and sad blue moats in the Loire Valley are particularly plaintive and memorable.
