The Philips CPO-T series of lamps seems to be one of the last developments of HID tech from Philips. I acquired a ballast and a lamp from two different forum members, who i'm very thankful to. When i got the ballast, the store that stocked the CPOs suddenly had no stock left anymore.

I specifically looked for the 45w one because the CRI is curiously low at 66 for the 45w one, and 70-73 for the higher powered ones. Most small MH lamps (like the CDM range) have a CRI around 80 or even higher. Efficiency seems to be roughly the same.

Subjectively this lamp is quite 'nice' in a way. It has a definite yellow hue to it. I would not mind to see this as outdoor lighting at all, while i acknowledge that objectively this thing has pretty mediocre color rendering.

This brings up a few questions to me:
- What is the difference between one of these, and a CDM or CDO lamp?
- Why is the CRI so low, compared to Philips' other modern MH lamps? I can tell that the amount of red light is very small compared to the large amount of green and orange in the spectrum, which makes the R9 (strong red) CRI reference color very muted.
- Why is the CRI of the 45w one lower than the higher powered ones? Is this a consequence of the low color temperature of 2800k compared to the 3000k or higher from the others?
- What gases and halides could be present?
- Do other 2800k or lower color temperature MH lamps exist?

In the attachment you'll find the spectrum graph. It is skewed towards blue (the amount of blue IRL is lower than in the graph), since i did not use some kind of matte glass in front of the spectrometer and i don't have a cosine correction filter or whatever it's called, to ensure with a point source the diffraction grating keeps working properly.
I can find the cosine correction filters in China for over 100 euro which is a bit much. Any sources for one for a lower amount of money would be greatly appreciated.

The CPO-T have Ce-Tl-Na.

CDMs are mostly intended for internal lighting, primarily shop lighting where as best as possible CRI is a first design priority. Cosmopolis lamps series is designed mostly for street lighting, where the best efficiency is a primary design goal, and secondary, there is a fight for a long life. And in the terms of CRI, anything that is better than HPS is okay

 

Life span is a big difference, i thought i read 20.000 hours for the CDM but turns out the CDM-t 35w only lasts for 6000hr while the CPO does... 36.000 hours. That's a very significant difference.
Efficiency is a bit better too (110 vs 90ish) but that's not a super huge difference.

90 vs 110 lpw is a very significant figure for city bean counters, they are running thousands of lampposts dusk to dawn!

I get that, but in practice the bowls of street lamps are so dirty here, that giving them a wipe down every so often would benefit efficiency more...
(Also i have no direct 45w metal halide comparison, a smaller lamp usually is a bit less efficient)

35W one is in fact 39W and there are also 50W CMH.