A while back i bought some 530 halophosphate 8w fluorescents from CP Lighting. When looking at them through a spectroscope, i noticed the spectrum wasn't quite like i'm used to with color 29 (530) halophosphates.

Now i have the spectrometer, we can see that the phospor is... Weird. It is a mixture of triphosphor AND halophopshate it seems. It has the big yellowish bulge associated with halophosphate lamps, but also the red, green and teal peaks associated with triphosphor lamps.
It is in a fixture with a plastic cover, blocking the little UV peaks.

Yet, they are stamped color 530 - low CRI. I wonder, why would they mix these two, and not choose one or the other? Is it like... Recycled phosphor?
If no one here knows, i'll send an e-mail to CP lighting. I wonder if they even know, heh. I still have to figure out the procedure to measure CRI with the Little Garden spectrometer. Perhaps they'll have to bump up the 530 rating to 630 or 730. I'm now also gonna get the 630 'Furniture White' flurorescent lamp that was sitting at a thrift shop. Might be the same phosphor blend, who knows. Hope it didn't get sold...

2nd attachment: 33 (640) actual halophosphate, for comparison. Has more blue colors of course. Lacks the extra emission in the green, the red, and maybe teal.

Second puzzling thing (3rd attachment): i bought an Osram 33/640 in the DIY store. I assumed i was buying one of the very last halophosphate lamps on our market.
Well... Seems like that's fully triphosphor! I have yet to measure the CRI, but it would be really odd if it were some highly specific low CRI triphosphor mix.

Finally, 4th attachment for comparison, an Osram 827.

Ha, I swallowed the hype and ordered that Chinese wonder, Little Garden spectrometer today too. Just could not resist for $62 shipped Spectral resolution looks rather good at such cost! Let's see next month...

Btw, have a local brand 40W circline here, mostly halo spectrum, but showing a little peak at ~611 nm typical for rare earth red. Not sure if it was just a coating machine not cleaned well enough, or was RE phosphor deliberately added to make CRI slightly better.

I know about the halophosphors tube with the red line in the spectrum. I don't know what it is, but it isn't YOX, as YOX have several lines in the red in additional dimmer lines in the orange.

But weaker lines of YOX are swamped in halo's continuous spectrum. At ~611mn it *should* be something europium in my lamp, not much choice. YOX or vanadate. You may have seen an old-school deluxe halo mix, it has fluorogermanate, with a peak at red, but much more deeper, about 658nm.

Ha, I swallowed the hype and ordered that Chinese wonder, Little Garden spectrometer today too. Just could not resist for $62 shipped Spectral resolution looks rather good at such cost! Let's see next month...

Btw, have a local brand 40W circline here, mostly halo spectrum, but showing a little peak at ~611 nm typical for rare earth red. Not sure if it was just a coating machine not cleaned well enough, or was RE phosphor deliberately added to make CRI slightly better.

very interesting on that spectrometer! I just watched a couple Videos on it, and it sounds very tempting indeed, I look forward on hearing how you get on with it or anyone else for that matter, especially when it commes to CCT and CRI calculations also

Can you export the raw data from your spectrometer, in a table of wavelengths and irradiance values?

If yes, I will share with you a home-made Excel file we use in Sylvania that will allow you to calculate all spectral parameters like relative illuminance, CCT, CRI, Chromaticity and a few dozen others.

I wonder though how precisely your spectrometer is calibrated.  That could be interesting to run a cross-check by measuring stabilised halogen and mercury calibration lamps eg on my system at work and then check on your device.  The halogen lamp is used to check its intensity calibration, the mercury lines to check its wavelength calibration.  Depending on its software capabilities it may allow you to recalibrate it to the known spectrum.  Or if not you could do a manual manipulation of its exported data in Excel, by correcting each wavelength’s measurement with the difference between what it actually measured and is supposed to measure for the halogen calibration lamp.

Yes, it should be possible to export the raw data, i just have to take some time to figure out how. I'll post again as soon as i know how.

Intensity wise, it's fully uncalibrated. I'm likely occasionally running into clipping issues.
Wavelength wise, you can two-point calibrate it on the blue and green spectrum lines of any mercury containing lamp.

I have halogen lamps, but i have no clue if they're close enough to the actual stuff to make it worth using one one of those.

The final issue is that whenever you use a diffraction grating spectroscope, the nature of the light (point source or illuminated surface) makes a significant difference. The suggestion is to fix this with some matte paper over the aperture, but that comes at the cost of a lot of light intensity and UV response. Will come back to this later with some proper photographic matte glass or something like it.

Indeed for any light measurement device you should take care to fully homogenise the light before the point of measurement.  It of course has to be done with a spectrally neutral diffuser.  Paper and sandblasted glass are far from suitable.  But you can easily and quite cheaply buy a so-called cosine correction filter plate.  Historically that was made from Russian Opal polished down into a flat glass-like disc.  These days it is made from Spectralon, a kind of PTFE/Teflon which has a flat spectral teansmission and reflection curve.  Normally I buy that in small discs about 3mm diameter to place over the optical fibre connected to the spectrometer.  Since you are in Holland you could probably best get that from the same supplier I am using, Ocean Optics of Duiven.