# Differences between high CRI fluorescents



## jtr1962 (Oct 12, 2004)

I've been using 5000K, 91 CRI fluorescents for about the last year and I'm generally very pleased with them. Lately, I've been doing some research and comparing spectrums. It seems that some are superior to others, at least on paper. For example, the Philips TL-D 90 Graphica Pro T-8 has a CRI of 98, a CCT of 5300K, and an efficiency of 64 lm/W. This compares to the tubes I'm using which have an efficiency of 92 lm/W. On paper the CRI 91 or 93 tubes seem to be much more spiky than the CRI 98 tubes. The more common commodity CRI 85 or 86 tubes have even more discontinuous spectrums.

Has anyone tried some of the very high CRI fluorescents? Is the difference even noticeable compared to CRI 91 tubes for most applications? While the higher CRI is an obvious benefit, the drawbacks include a much lower efficiency and a much higher price (frequently over $15 as opposed to the $7 I paid for my tubes). Is it even worthwhile to consider switching at some point in the future? Please note that my main use here is general lighting. I'm using or plan to eventually use some type of high CRI tubes in all the rooms where I live. I'm curious as to whether or not I should standardize on CRI 98 tubes or just stick with what I have. Please note that headaches or other physiological effects are not a problem here. In fact, I'm fine even with commodity grade CRI 86 tubes (although anything much less than that causes problems). I'm more concerned with the general color and appearance of things.


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## Wim Hertog (Oct 12, 2004)

I´ve used the philips TLD-series and from what I understand they are using a halophosphate mix, not the newer rare earth phosphors. These halophosphate phosphor mix combined with special filters inside the tube to filter the mercury spikes gives a very high CRI value, but low efficiency. Your tubes are using a mix of 5 or more rare earth phosphors. These phosphors will give you a CRI from 90-92 and a good effciency (altough 92lm/W seems very high...).

The philips tubes look more pinkish, the other high CRI tubes look a bit greener. 

So yes, they look better, but their efficiency is so low....I would use the newer tubes (rare earth phosphors, CRI of 90-92).

If you have any questions, feel free to ask.


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## jtr1962 (Oct 14, 2004)

The tubes I use are here. Look for Maxum 5000 F32 T-8. One reason I chose these tubes is because of the high efficiency combined with good color rendering.

My main question to you is are the differences between the Philips TLD tubes and something like GE Chroma 50s (or my tubes which have a similar CRI) noticeable to the untrained eye? That would be my only reason for contemplating a change. The tubes I'm using look better to me than any other tube I've tried. While the TLD series might look even better on paper, I'm curious if it would make much difference in the real world.


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## Wim Hertog (Oct 14, 2004)

Yes, the differences are visible. The TLD-90 graphica pro looks a little bit more pinkish then the other ones I tried (newer philips TLD-90, CRI92). The graphica pro series are A LOT dimmer then the newer TLD-90 series.

I can send you some pictures of my hand (to see the skin tones) for the TLD-90 graphica pro compared to daylight and to a fluorescent with CRI92, color temperature 5500K if you give me your email adress. 

In Belgium, the TLD-90 pro (CRI98) is around 5 euro/lamp if you buy them in large quantity (25).


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