Ultra-detailed restoration and sharpness enhancement of a vintage photo. Recover fine details and improve clarity, especially on faces. Remove all scratches, dust, stains, tears. Preserve natural film grain. Correct geometry and tonal range. 
Then, colorize it to look like a historical color photograph: natural, muted, historically accurate colors. Avoid plastic skin, oversaturation, digital painting look, and oversharpening artifacts. Museum-quality realism.