Author Topic: HQI-BT 400W/D with poor CRI?  (Read 442 times)
Hxa
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HQI-BT 400W/D with poor CRI? « on: March 22, 2020, 01:09:23 PM » Author: Hxa
I have many years old Osram HQI-BT 400W/D in random use. It has great CRI.

I bought a couple of same model lamps (new, unused ones). When I tried the new lamp, it had a little bit bluish tint and worse CRI compared to the used lamp. I tried the other new one and it also had this same bluish tint and poor CRI.

Will the new lamp correct its color rendering and color when I use it a couple of hours? How this could ever be possible when I use the same lamp model with exactly the same gear?

The lantern is a Idman lantern typed for a HPI-T 400W lamp.
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sol
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Re: HQI-BT 400W/D with poor CRI? « Reply #1 on: March 22, 2020, 01:34:12 PM » Author: sol
Usually, you need ~100 hours of "burn in" time before the CRI stabilises.

I have noticed that with HID, different batches have slightly different colours (and CRI).
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Hxa
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Re: HQI-BT 400W/D with poor CRI? « Reply #2 on: March 22, 2020, 01:44:36 PM » Author: Hxa
Many thanks for your reply! First I was about the take the new lamp down but now I will use it and see how it acts.

At this moment they look way too different what comes to batch difference you mentioned. Let's see what happens.
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dor123
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Re: HQI-BT 400W/D with poor CRI? « Reply #3 on: March 23, 2020, 12:32:11 AM » Author: dor123
Perhaps you bought fake lamps? If they had bluer color than your original HQI-BT 400W/D, this means that the halides chemistry is different than the original lamp.
Also: You need a HPS ballast to run the Osram HQI-BT 400W/D at optimal CRI. Otherwise you will get a greenish color and poor CRI.
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I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the European date format (dd.mm.yyyy).

I lives in Israel, which is a 230-240V, 50hz country.

Medved
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Re: HQI-BT 400W/D with poor CRI? « Reply #4 on: March 24, 2020, 09:15:00 AM » Author: Medved
With a horizontal double ended CMHs I've observed color shift when the lamp was rotated in the socket. After some hours it settled back again. I attribute the change in the halide reservoir pool, normaly residing at the lowest point, becoming just above the arc (so likely the hottest point). That of course changes the pressures so color, till the pool redistlles to a coldest spot again.
So I guess it would be your case as well: The pool was formed on one spot when manufactured, but then shifts to really the coldest spot after the lamp is used. Of course, this effect is most likely perfectly known to makers, so the lamps are designed for rated performance AFTER their burn in (about 100 hours), when these things do settle.

Plus there is another effect: Quartz MHs tend to run hotter as they age, which tends to shift their CCT down (and CRI up; but the efficacy becomes lower). So the new lamps may well be performing as originally rated, only the old one may well improve its light quality just for short time before dying...
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Hxa
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Re: HQI-BT 400W/D with poor CRI? « Reply #5 on: March 25, 2020, 02:03:59 PM » Author: Hxa
After couple of hours burning, CRI of the new lamp seemed bit better.

The new lamp gives more light when compared the old one. So maybe the older one runs hotter as Medved said Bulb Man
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dor123
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Re: HQI-BT 400W/D with poor CRI? « Reply #6 on: March 26, 2020, 01:03:10 AM » Author: dor123
The rated CRI of HQI-BT 400W/D is 92, and there are lots of Chinese ripoffs of this lamp, which have different filling that gives poor CRI.
I think your new lamps are fake, and are filled with indium or other halides rather than dysprosium-thallium-caesium.
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I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the European date format (dd.mm.yyyy).

I lives in Israel, which is a 230-240V, 50hz country.

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