Posts 23,959 Likes 53,232 Dan S ·Feb 10, 2025 Blue dials from that era are notoriously unstable and ultimately lose color completely. I don't think you can extrapolate to a brown Speedmaster dial.
Posts 13,128 Likes 22,788 Davidt ·Feb 10, 2025 I’d agree both are unstable but due to different factors and thus have different modes and rates of deterioration. Blue dials for example often lose their finish entirely around the lume plots and fade to an unattractive grey hue.