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flourescent light flicker
I am an expressions newbie. Trying to do something which seems like it should be simple but it just isn’t working correctly. I’m trying to create a “busted flourescent light” effect where the light flickers, foreshadowing the impending doom facing our heroine. I’m trying to use an expression to wiggle the output whites and input blacks. But it’s coming out like a 1-0 effect. The screen is either black or 100%. Any thoughts?
I posted this on the expressions forum also, but this forum seems like it’s a lot more active.
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7 Replies
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I assume you’re using the Levels (Individual Controls) effect. Well my friend, Levels works in strange ways! 0 is equal to 0, but the maximum value of a pixel in a channel, as far as Levels is concerned in non-32bpc, is 1.
So when you wiggle your value make sure you’re wiggling between 0 and 1, not 0 and 255.
Darby Edelen
DVD Menu Artist
Left Coast Digital
Aptos, CA -
I had good success with a similar effect just wiggling the opacity of my hero light layer. If you make the values vary enough and the period short enough is pretty convincing. But it may not be good enough to meld with live action…
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Well, that explains the seemingly binary outcome of what I did. There must be a workaround, though. Precomposing? A null object?
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[cmcilwain] “There must be a workaround, though. Precomposing? A null object?”
Sorry, I thought I gave you the work around. Make sure you’re wiggling your values between 0 and 1. Wiggle() will generate floating point numbers so it should work fine with Levels (Individual Controls) as long as you wiggle between 0 and 1.
Darby Edelen
DVD Menu Artist
Left Coast Digital
Aptos, CA -
I think I may not have been clear when I said that Levels works with numbers between 0 and 1 before… It’s not binary (on or off), 0.5 for example is ‘half on’ or ‘half full value.’
If you want to deal with values in the range of 0-255 (standard 8bpc)you can simply divide your values by 255, resulting in the proper floating point value.
255 / 255 = 1
128 / 255 = 0.502
0 / 255 = 0Darby Edelen
DVD Menu Artist
Left Coast Digital
Aptos, CA -
Ahhh. There it is. Thanks so much. I misunderstood the first time. That’s definitely it. Wiggling the blacks give it the organic feel I was looking for. The only drawback is the input black goes to an extreme black, making the effect a little bit more intense than I need. Is there any way to control the range?
Thanks again.
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You just answered my next question. Nailed it. Looks awesome. Thanks again for your help!
Christian McIlwain
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