I found an Osram fluorescent lamp at the thrift shop. Color 15 is supposed to be just 'daylight'.

However, this lamp is stamped with 'daylight deluxe'. If i browse the pre-1970 catalogs, color 15 refers to daylight. The 1970 catalog calls color number 15 'Daylight deluxe'.

So what is this exactly? Is this a normal ~75 CRI daylight lamp, or is it more special?

Look at the spectrum in deep red. Deluxe lamp likely will be doped with some deep red emitter like fluorogermanate @650nm approximately.

You can also compare it visually to regular /765 - deluxe lamp will look whiter with more red, /765 will look more greenish.

Sometimes i forget i actually have a spectrometer. I'll post a comparison between a common daylight 4w tube and this one, if they turn out to be different. Spectrometer is now at work because i used it there.

It turns out to be an actual Deluxe tube which is nice, and not just a conventional color 15 one that was stamped 'deluxe' because even ordinary daylight halophosphate lamps have a higher CRI than cold or warm white halophosphate tubes. It has a clear 655nm hump. which i think corresponds to magnesium fluorogermanate. Very happy that i bought it. If anyone has more information about it like age, CRI (the spectrometer can technically measure it, but i lack the proper diffusing filter making it quite inaccurate), if the Deluxe variant of this tube is common or not, efficiency etc.
It looks like it is not very efficient, judging by eye. Not that i mind. Even at 40lm/w or so it's enough for my kitchen.

A nameless 4w daylight tube does not have that 655nm hump.

Odd that they still chose to call it color 15, while Philips had specific color codes for their Deluxe tubes. One could easily confuse the deluxe tubes with normal ones.

The Deluxe feels more neutral in color. It is much nicer to have it as room lighting than the normal ones. It actually does match the light of a cloudy sky very well, which is beneficial because my kitchen is in a dark-ish corner. 
However, i find the common daylight color quite striking. Not at all as whole room lighting, but there's definitely benefit in treating it as some kind of accent lighting, not unlike actual colored lights.

In the end, i'll just keep swapping around various lights in the kitchen. There's also an SDW-T hanging out there, though a 100w one which does a fine job at replicating the brightness of sunlight lol

Hello Laurens,

a small addition from the waste paper:


Source: OSRAM tonalità di colore lampade fluorescenti marzo 1972



Source: OSRAM tonalità di colore lampade fluorescenti marzo 1972

If I have correctly recognized the stamp with “uGX” on the photo, then the lamp was produced in Augsburg in October 1975.


Regards

Olav

Thanks!

Interestingly the color daylight deluxe is indicated with 19, and the spectrum corresponds with it rather than 15 - daylight extra.

I have another Osram daylight tube somewhere, i'll test that one too as soon as i find a 15w ballast.

Nice add to your collection. The Osram color /15 haven’t been marketed in Switzerland. We had only the /10 and /19. One reason is maybe because Osram had its own fluorescent lamp factory in our country but they made only standard colors including the /10 daylight.