to fade (of a colour); to grow dull in color (colour)
to lose vividness; to lose freshness; to grow stale; to pale
写真の色が色褪せた。
The colors in the photo have faded.
古い布が長年で色褪せている。
The old cloth has faded over many years.
記憶というものは時間とともに色褪せるものだ。
Memories tend to fade with time.