Mixing led and CRI


Back in the mid 90s, at work, I had hundreds of 8 ft florescent fixtures. They were all toward the “warm” 2700 range and gave the product a yellow tinge. To get high CRI tubes were several times more expensive. So I started to mix “daylight” tubes. By themselves, they washed out the product, but in combo they worked out pretty good. And CHEAP. Daylight and warm were the same price.

For the record, I had no means to measure CRI, the mixed tubes were closer to what we thought was “neutral” color.

So this preamble goes to the question, does careful mixing of LEDs create a better CRI?

Is the price spread to high CRI LEDs minor? I’m not talking about just enthusiast mods, I’m thinking mass produced lights.

Which will lead to another question, why did the stupid city I live in choose pole fixtures that completely wash out color.

1. That is called tint mixing. It doesn’t result in better color rendition, but it does result in a better beam and better tint.

2. Usually, if the light comes with high CRI LEDs and low CRI LEDs by default, the price delta will be minimal, negligible, or even non existent.
Otherwise, special editions of lights might actually cost more.

One example would be the SST-20 5000k vs SST-20 4000k 95CRI. There isn’t a cost difference between them.

3. Cost, and efficiency. Lower CRI and higher color temperature light fixtures(6000k+) are more efficient than higher CRI and lower temp ones(5000k and below).
Why? To achieve the same output, you need more LEDs, and better heatsinking, which drives up the cost.

Most people don’t care about high CRI lighting until they’ve actually seen it. So, cost+efficiency is a priority to them.

4. In response to this however, knowing that higher CRI makes color rendition better and that lower CCTs help with night vision, low CCT (4000k and below) and high CRI lights might be more efficient in terms of visibility at night.

Osram already makes multi-die LEDs with different colour temperature per die to give more even spectrum coverage.

A few companies actually… even adjustable CCT


About two years ago I looked at changing to LED fixtures. Wow….Osrams were 400-500 per fixture. I think they were 90 CRI.

Mixing high CRI lights will reduce the CRI. The mixed light is on a direct line between the two in the (ANSI) color range diagram.
It is below the BBL so the tint may look okay but it is not high CRI at all.

Btw high CRI is not a good thing for street lighting. It would be more important to reduce light pollution by reducing the blue spectrum to avoid disturbing people’s day-night-cycle and to attract and kill less insects.
Unfortunately cheap street lights are often cold white LEDs because they deliver more lumen per $$$.

HI CRI lights that emit very low amount of blue wavelengths would be great for street lighting. The E21A 2000k 9080 emits very little blue wavelength light in its spectrum but still works very well for color rendering at night