We have a "Shop-Lite" in our shed, With 4 F32T8 (On Instant Start) tubes, But the package for them says: "Philips F32T8 2850 Lumens 75 CRI". The problem is, It gives 2850 Lumens which indicates Triphosphor, But the CRI is only 75, Which indicates Halophosphor.
If it was Multi-Phosphor, It would have 97 CRI.
Deluxe Halophosphor would have a CRI of about 90, With really low lumens.
How could this be?

Tri-phosphor does not automatically mean high CRI. It only allows to nix the components so, the CRI can reach the 80's. But the mix may be tuned for other objective and then the CRI may get lower.
E.g. if someone reduces the relative red or use orange instead in order to boost the efficacy (the same power radiated in green gives off double lumen output than with red, orange emits about 50..60% more light for the same power, yet still allows to reach the overall white color), the result will be greenish hue with somewhat worse red rendering and the overall efficacy may increase by about 10..15% without really achieving higher energy efficiency (so requiring the main tube design change).

It's just like that with LEDs.
What is more confusing is that these tubes seem to be a rarity, Even though Home Depot has loads of these.
Could it be something other than Triphosphor?

Last time I was there, my local ReStore had some Philips Alto F32T8/Daylight lamps. They had a CRI of 75, don't remember the lumen rating. I almost bought a couple just to see halophosphate daylight F32T8s. I may still if they haven't sold yet.

Last time I was there, my local ReStore had some Philips Alto F32T8/Daylight lamps. They had a CRI of 75, don't remember the lumen rating. I almost bought a couple just to see halophosphate daylight F32T8s. I may still if they haven't sold yet.

I'm confused.
Halophosphate or Triphosphor?

I believe they were halophosphate. If they were triphosphor, I'd expect them to be labeled F32T8/765.

Then I guess a spectrometer would prove it.
If it is Halophosphate, Then the only thing that could make it better is that the tubes use 580 (50 CRI, 8000K) phosphor.

 - Old 640 (That is 4000K Cool White Halophosphor) 40W T12's were rated at 2850Lm

 - Over here, 36W T8's take 36W (lamp power not including ballast losses), replace 40W T12 (that take 40W) on the same ballasts, and put out really the exact same light, not "a bit less" as one would think from thinking "36W vs 40W"

 - The same 36W T8's take 32W power when used on Electronic ballast, still with the same light output



And there you get - it is very possible Halophosphor T8 that uses 32W on electronic ballast and puts out the same 2850Lm as 40W T12

Out 36W T8s are not same voltage/current/gas fill as the US 32W's, but if it is possible, then it is possible



The higher CRI can be result of a bit better phosphor than the ordinary 640. Its not the "standard Triphosphor" mix thats im pretty sure (standard Triphosphor lamp at this wattage would be at 3200+ Lm and 80+ CRI). Maybe it is some cheaper version of the Triphophor mix, maybe it is an improved Halo, maybe it is Halo with a bit of Rare Earth phosphors (what is used for Triphosphor) mixed in, Maybe any other possibility

- Old 640 (That is 4000K Cool White Halophosphor) 40W T12's were rated at 2850Lm

 - Over here, 36W T8's take 36W (lamp power not including ballast losses), replace 40W T12 (that take 40W) on the same ballasts, and put out really the exact same light, not "a bit less" as one would think from thinking "36W vs 40W"

 - The same 36W T8's take 32W power when used on Electronic ballast, still with the same light output



And there you get - it is very possible Halophosphor T8 that uses 32W on electronic ballast and puts out the same 2850Lm as 40W T12

Out 36W T8s are not same voltage/current/gas fill as the US 32W's, but if it is possible, then it is possible



The higher CRI can be result of a bit better phosphor than the ordinary 640. Its not the "standard Triphosphor" mix thats im pretty sure (standard Triphosphor lamp at this wattage would be at 3200+ Lm and 80+ CRI). Maybe it is some cheaper version of the Triphophor mix, maybe it is an improved Halo, maybe it is Halo with a bit of Rare Earth phosphors (what is used for Triphosphor) mixed in, Maybe any other possibility

Could I supply you with more info to see what these tubes are?
Some things it says is ALTO II And "Made in U.S.A.".

What comes after "F32T8" on the etch?

What comes after "F32T8" on the etch?

"/DAYLIGHT"
Would a photo help?

Aha, so they are the same ones I saw at the ReStore. Here's a quick test you can do: hold the shiny side of a CD near the lamp, and you will see a "rainbow" on the CD. If the colors blend smoothly (like a typical rainbow), the lamp is halophosphate. If you see three distinct bands of red, green, and blue, it's triphosphor. It helps to do this with a known halophosphate lamp and a known triphosphor lamp beforehand so you know what to look for.

If the light had a magnetic ballast, you could use the old cell-phone-camera trick to see the color of the afterglow.

Aha, so they are the same ones I saw at the ReStore. Here's a quick test you can do: hold the shiny side of a CD near the lamp, and you will see a "rainbow" on the CD. If the colors blend smoothly (like a typical rainbow), the lamp is halophosphate. If you see three distinct bands of red, green, and blue, it's triphosphor. It helps to do this with a known halophosphate lamp and a known triphosphor lamp beforehand so you know what to look for.

If the light had a magnetic ballast, you could use the old cell-phone-camera trick to see the color of the afterglow.

What's this cellphone camera trick?
Anyway, I can't tell if it's smooth or spiky, It changes with your angle.
For the afterglow, It's on Instant Start, But every time I turn it off, I notice a long, Green afterglow.

The camera trick simply involves holding a cell phone camera up to the lamp while it's lit and looking at the color of the stripes. Examples:

Triphosphor (green/yellow)
Deluxe Halophosphate (dark green or black)
Beryllium (top) and Halophosphate (bottom) (red and yellow, respectively)

The reason you need a magnetic ballast is that electronic ones operate at very high frequency, so no stripes will show up. Also, looking at the lamps immediately after they turn off has never worked well for me. For some reason, I find it difficult to determine the afterglow color that way. Maybe it's just me, though.

The camera trick simply involves holding a cell phone camera up to the lamp while it's lit and looking at the color of the stripes. Examples:

Triphosphor (green/yellow)
Deluxe Halophosphate (dark green or black)
Beryllium (top) and Halophosphate (bottom) (red and yellow, respectively)

The reason you need a magnetic ballast is that electronic ones operate at very high frequency, so no stripes will show up. Also, looking at the lamps immediately after they turn off has never worked well for me. For some reason, I find it difficult to determine the afterglow color that way. Maybe it's just me, though.

My tubes look more "LED green" than any of these. Looks a little like Triphosphor and Deluxe Halophosphate.
Maybe if your camera is super quick, You could see the stripes.
I could take a photo.