@Brandi 

You can create a schedule and set the fade rate. Here is an article that should show you how: https://www.tp-link.com/us/support/faq/2702/

@Tony Thank you! Can I use a schedule to create a fade on demand? I'm thinking of a way to (for example) press power and the bulb fades out, starting immediately over the next 20 minutes? Or would I create a schedule and then set the fade to occur as soon as possible? Thanks again for your help with this!

@Brandi 

Unfortunately not on demand, the fade rate can only be done when creating a schedule.

@Tony doing it as a part of a schedule is okay, but can this be done as a scene that I can apply to a routine?  This would be much better and more useful.

@jtb2inky 

That would not be possible, when creating a scene you are able to call presets, but can't call the fade rate function.

When I looked there is the ability to create a routine in Alexa, where you can call the fade rate, I forgot to also check the power, so you can set the brightness level, and how long it will take to get there:

@Tony  I'm also interested in this question as I've now got enough bulbs / switches to make scenes controlled by automation more useful than individual device schedules. 
 

ive had a look at Alexa but I can't see that fading option for my dimmable bulbs. Do you need to do anything special to get that? 
 

Thanks

@Phil_B 

Here is what Amazon references to do that: 

1. Open the Alexa app .
2. Open More  and select Routines.
3. Select your routine, and then Add action.
4. Select Control Device, and choose your dimmable light.
5. Select Brightness.
6. Use the slider bar to choose your starting or ending brightness level.
7. Select Ramp to Brightness.
8. Add the length of time for the light to ramp up or down.

@Tony The ramp option is not there if I am setting an action for a group of identical lights. 
 

If I set the action on just one bulb, I see the ramp option.  
 

bug?

Thanks for your helpful answers!

jason

More accurately:

 select named group: ramp available

 select all bulbs: ramp not available

 select one bulb: ramp available

 j