Appropriate synonym for lights brightening gently
Here are some phrasal options for you.
I recommend using an adverb like gently. Here are some phrases using adverbs that I think evoke a soft brightening:
- the lights gently rose
- the lights came up gently
- the lights brightened softly
These sentences invoke metaphors: In the first two, the metaphor is of light rising; in the third, the metaphor is of a gradual change being soft.
Similar options:
- the room brightened smoothly
- then, smoothly, all darkness abated
- light fluidly diluted the darkness
fade up
From the Wikipedia entry on dimmers: "In the professional lighting industry, changes in intensity are called "fades" and can be "fade up" or "fade down."
Two examples of common usage:
The glaring white lights dimmed and a new light focused on the runway and generic alternative music pumped out of the speakers.
And when the show ended and the lights faded up once again there was not a single word written on my notepad.
Source - The Tourists: A Novel by Jeff Hobbs
"Right," Rupert said, "but have a look at this before you go. Not many kids get a chance to come backstage."
As he spoke, he reached out and rotated a large knob, and the lights faded up on the stage below us.
Source - The Weed That Strings the Hangman's Bag by Alan Bradley
Consider "rise", which is sometimes used to refer to a relatively gradual increase of illumination, such as after the conclusion a theatrical performance, as in, "the house lights rose".
This sense of the word is defined by oxforddictionaries.com as
Increase in number, size, amount, or degree