Let's say the following options are available from a given manufacturer for a given model of LED:
- 6500K, mid-low intesnity, <60 CRI : Easiest to hit because it's what the process naturally favors. The market will have them available in large quantities for cheap because it's easy to produce.
- 4500K, mid-high intensity, 80 CRI : Obtainable at distributors like Digi-key or Mouser, low availability or out of stock, and always more costly than the previous option.
- 3500K, high intensity, 90 CRI : Apt to be very hard to source at common distributors - it may in their catalog but perpetually out of stock - and is going to be expensive
- 2900K, highest intensity, >90 CRI : May be best described as 'unobtanium' and may only be available directly from the manufacturer ... at a premium price
In reality, most manufacturers will spec a wide range of CCTs, outputs, and CRI bins
(mercifully, they've generally eliminated forward voltage bins) in their specification sheets. What said spec sheets won't tell you is what's reasonably
available from the broad spectrum of possibilities.
Lots of explanations here !
So there is no "higher grade" dies, because a "low quality" die usually has a better CRI if my understanding is correct ?
The general tradeoff is high CCT/output results in low CRI and vice-versa. While manufacturers can produce LEDs that better balance these traits, they tend to be rarer and thus more expensive. It could be low availability of blue LED chips that hit a precise frequency range, the random availability of
really good phosphor mixes, some subtly-yet-impossible-to-nail-down-
why better binning on one of the assembly lines, etc.
But your question depends on one's definition of
quality. For most flashlight usage the priorities are output, CCT, then CRI; brightness/efficiency are primary selling
and utility points, tint is an important perceptual point
(cooler tints are perceived to be brighter for otherwise-same output), and CRI isn't terribly important for most users. For fixed-lighting usage (think light fixtures) it's different - CCT, CRI, output; CCT is crucial since the residential market prefers that incandescent-like 2700K while the commercial market is more about fluorescent-like 4000K, CRI is nearly as important since fixed lighting is for sustained use, while output is less important since pretty much all light fixtures will use scores of emitters to hit target output levels. These two cases are generalizations of course - specific products may have markedly different requirements: a dental instrument might need moderate output, high CCT, and highest possible CRI ... a special-use flashlight might need high output, neutral CCT, high CRI.