Kruithof curve (warmer light when it dims). Dimming THE ROOM vs, naively, equally dimming all dimmers in the room

[chefdeit]

Describe your core improvement

The Kruithof curve https://en.wikipedia.org/wiki/Kruithof_curve describes that the dimmer the lights, the lower/warmer their color temp should be in order to appear pleasant and natural/neutral and not ghastly to a human eye. Color temperature together with the light level also plays a massive role in helping regulate vs disrupting our circadian rhythm (see https://pmc.ncbi.nlm.nih.gov/articles/PMC8274909/ ).

For RGBCCT and other color-changing light strips and bulbs, I'd like to be able to tell HA what lights are what output levels and color temperature ranges, and choose the Kruithof curve tracking option vs the current behavior. The former lets HA dial in the color temperature appropriate for a given brightness / dim level a user picks in a given area / room (or an individual light if it's color-changing).

If the room doesn't have a variety of different color temp lights for HA to maneuver, or their max light output, color temp, and role (fill / navigation / task or feature) aren't defined, the HA falls back to its current behavior.

Current limitations

Currently we can only hard-code multiple fixed brightness-color temp pairings for each light using scenes and such, to sort of get a couple proper levels. And it needs to be re-done when some light or dimmer has changed. Tedious, redundant, and maintenance-intensive. And there's little if any code transferable from one HA user to another in the community, in terms of improved quality of life in this area by means of Home Assistant.

Technical benefits

This becomes particularly interesting in the context of dimming an Area as opposed to dimming a specific fixture. Since we still live in an infancy of mass-market lighting, no single fixture can properly accommodate the full Kruithof range, from "wake me up & keep me awake" 5000K at 2000 lux (bright enough to fix a wristwatch movement) to "I'm slowing down for the night" deep amber 2000K at 0.2 lux (a couple candles). But a room can have layered lighting, with a variety of fixtures. I can have a bunch of high-power cans at 5000K temp, at 100% brightness netting 2000 lux. The same room can have 2000K amber bulbs for the more intimate evening-related task and feature lighting plus RGBCCT led strips at the crown and/or baseboard molding.

When I dim a room (Area), the Kruithof-aware HA should know better than to just naively try to dim the twelve 250-watt daylight cans AND 6 watt amber bulbs AND the LED strips all to 0.01%. It won't be able to, as there's not enough resolution in a regular dimmer or LED driver. Nor would it be necessary. The Kruithof-aware HA would know that all those 5000K cans should just be off, that the amber bulbs should be at 15%, and that those RGBCCT strips should all glow say just the warm white at 10% plus red at 2%. Because it's dimming THE ROOM - which is less naive than dimming all the dimmers in the room to the equal value.

Additional context

If HA becomes aware of the fixtures' role (fill / navigation / key or task or feature) and output level and color temperature, it can manage dimming the room in a smarter and more transferable & maintenance-free a way more in line with the user's informed intent out of the box.