realistic lightbulb flashing?

[David Bogie]

An incandescent bulb has a ramp cycle that’s easy to simulate. Heck, you can shoot video of a light bulb turning on and off (lock the exposure) and just matte that in.
LEDs are instant on.
Some CFLs have a very short burst when they fire up and then they ramp up slowly oer five minutes if they’re completely cold.
Other CFLs are instantaneous or even dimmable

Your phrase, ” a very realistic light to emit from it” is puzzling. That’s a completely different topic from attempting to simulate the filament lighting up.

bogiesan

This is my standard sigfile so do not take it personally: “For crying out loud, read the freakin’ manual.”

[David Lieberman]

hello, thanks for the help.

I think you misunderstood me a bit. im not looking for a gradual light to turn on…im literally just trying to create the illusion of the lightbulb being cutoff for split seconds… i tried flares and everything else but cant make a realistic light that will keep jumping up and down in exposure/intensity… I havent got the time, nor the equipment to video tape a real light bulb and then rotoscope it to fit my composition…

thanks,

david.

thanx for the help.

[Brian Charles]

I’m not sure I understand your need either however you could use a point light and animate the intensity value. To add more realism to the scene you could use Levels or Curves to increase the brightness of the other objects in the scene.

If you’re trying to simulate a light beam or source you could use Peter Torpey’s Volume Light script. Or Trapcode’s Lux.

[David Bogie]

> i cant manage to create a very realistic light to emit from it… im trying to make the lightbulb flash on and off repeatedly like in those thriller films when the electricity of the building keeps jumping, if that makes any sense? < I didn't misunderstand. Your question makes no sense. A flickering light bulb is easy to create. A flickering light source is a completely different animal and your second post doesn't help clarify your needs in the slightest. There is a random expression that can be dropped onto your parameter in a few seconds. > trying to create the illusion of the lightbulb being cutoff for split seconds… i tried flares and everything else but cant make a realistic light that will keep jumping up and down in exposure/intensity… I havent got the time, nor the equipment to video tape a real light bulb and then rotoscope it to fit my composition…

You’ve already established that it’s going to be easier to shoot a real light bulb than for you to attempt to simulate it with software. Flares? You shot like an emergency road flare? You mean lens flares? Which is it? Why would you use a lens flare to simulate a light turning on and off.

bogiesan

This is my standard sigfile so do not take it personally: “For crying out loud, read the freakin’ manual.”

[Adam Hummell]

In response to the “help” from mr. David Bogie.

Of all the responses I’ve read on Creative Cow, this is the most pathetic attempt to insult somebody while making yourself sound superior.

From what I gathered, you sound like you actually know how to help david lieberman, instead you’ve chosen to highlight his questions and comments in a way that is belittling.

this post is indeed old, but obviously relevant because users often have the same questions years later.

to answer david lieberman’s question:

there are many ways to create this “flicker/horror movie” light.

the simplest but harder to control solution is a wiggle expression linked to your opacity.

alt + left mouse click on your layers opacity and add this expression

wiggle(f,m)

for example you would write: wiggle(5,100)

the f relates to the frequency(how many time per seconds), the m relates to the magnitude(the intensity of the change)

the easier method would be to use the wiggler:

1) in after affects –> window drop down menu –> select the wiggler

2) position two keyframes in your opacity. One for the beginning of your scene and one for the end (you can even start your keyframes at 0% either way that part is for your own personal choice of animation)

3) with the two keyframes selected, adjust the frequency and magnitude. (you’ll have to play with these settings to figure what looks right for you) I would suggest noise type “Jagged”

4) hit “Apply” and it will generate a bunch a keyframes in between the selected keyframes. these are all adjustable, if you don’t like them you can just delete them start over or delete the ones you don’t like.

about creating a light,

super fast solution: draw a solid round shape with the ellipse tool. put a nice feather on it, add some glows, maybe make a second small shape and put it over top of the bigger shape reduce the feather for variety, increase the glow and put it on “add” blending mode etc. you should eventually come out with a useful light.

now use that wiggle technique on the mask expansion instead of the opacity (it will look a lot better because it will preserve the glow)

this is a very quick light, I don’t suggest this if you need something custom. This will work tho, and it’s better than a lens flare.