After this they were silent as day darkened slowly into night.

The light slowly darkened in spots and took on a pattern.

Darkening slowly fades and we see it much as before.

Outside, the evening slowly darkened into night and the lights went on at the docks.

Framed by their weeping branches, the river water slowly darkened to black.

She paused for a moment, staring out the living room window, watching the gray sky as it slowly darkened in color.

Kuo came down alone and his face darkened slowly as the green light faded from the sky.

Getting up from the table, he went to peer out around the edge of the window curtain, into the slowly darkening afternoon.

The pain was fading, the sky in Rum's eyes slowly darkening.

The field slowly darkens until it's just silhouettes racing in the night.