Posts 21,586 Likes 48,910 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 11,958 Likes 20,785 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.