When using transitions turned off lights will first show previous color

Hi,

I’ve been busy migrating my HUE Zigbee lamps to HA via Zigbee2Mqtt and I basically want to mimic my previous HUE setup. While setting everything up I found out that the transitions work a bit differently when turning on a lamp. I did some research and I’m quite confident the issue lies in HA’s way of transitioning.

What the heck explanation:

  1. I have a scene which (for this example) turn the lamps to a green color with a transition of 1,5s
  2. I turn off the scene/light
  3. I turn on a different scene which turns the lights to white with a transition of 1.5s

The weird thing is that at step 3 the lights turn on starting with green then transition to white. I would have expected it to turn on dimmed white and then transition to bright white.

Visual explanation:
image

I think it can be solved by first change the color of the lamp before turning it on for the transition.

As far as I know this is a limitation of the light technology. @123 knows more about this topic. I have the same behavious with my Hue bulbs and this can’t be changed as far as I know.

But if it is a light technology issue, wouldn’t Hue then also have this issue?

That’s a behavior I have noticed with my Philips Hue Color bulbs. Upon turning on, they remember their last state (color, brightness, etc). So if the last state was green at 100%, if you send a command to turn on red at 75%, the result will be a momentary display of green (its previous state) before it assumes the new state (red).

As far as I know, there’s no way to “preload” a color (or brightness) before turning on the light. In other words, send “red at 75%” to the bulb while it is off (effectively making it the new "previous state’). So when you do turn on the light, it immediately becomes red at 75%. However, none of this possible with Hue bulbs. FWIW, it is possible with LIFX bulbs (according to the LIFX integration’s documentation).

That’s probably some functionality that is proprietary to their software.

Maybe @Koenkk knows?

It sounds like two separate commands are sent: 1) turn on, 2) set the color to white. Instead, a single command should be sent: 1) turn on to white.

This is a platform specific issue, LIFX actually had the same problem long ago: https://github.com/home-assistant/core/issues/2472

Sorry for digging out this old post…but i haven’t found a way to PM svh1985…

@svh1985 Have you found a solution for this topic!?