“Luminous pigments are classified by daylight or body colour and an emission-colour which do not have to be identical”, explains in TRITEC site. It means the luminous pigments can be designed for a same colour for day time and different emission colour for night time. Day time the colour can be C1 or C3 but night time can glow with different colour and intensity. This classification is normalised with ISO 3157 and ISO/DIS 17514 the body-colours are standardised for timepieces: Anyway tritec site states that any coloration of the basic natural colour reduces the afterglow intensity, like we can view in the picture
The classification ISO 3157 for body when is not glowing is,
C1 Colour “C1” for white
C3 Colour “C3” for yellow
C5 Colour “C5” for greenish-yellow
C7 Colour “C9” for blue-green
If we compare the body colours with the brightness, 30’ after, we look that C1 white colour with an emission white is lower that the most of colours. The body colour as BWG-9 is second in brightness; the emission is not white but blue or green, generally.
When we started this project, we wanted to put white luminova on dial, handles and bezel, as in body as emission night time colour. We know that the white emission is lower than other body. The idea was to put this pigment white colour as on dial as handles and bezel, but we changed the opinion, because the night image would be homogenous excessively. We thought that had so many watches in the market, seeming car headlights told us a swiss manufacturer. So we choose what we considered a better design.
Red luminova on the bezel, the watch looks like very nice night-time although is not as brightness like another kind of luminova. As well, this white luminova is very difficult to achieve. The picture was made with a several second of exposure.
Comparative between 2 Luminova on our dial
With a 30”exposure