• Adobe After Effects Expressions

  Instant color change on layer every few frames.

  Posted by Joey Harvey on February 6, 2014 at 10:21 am

  I am trying to get a layer to change colour instantly every few frames but stay within set range eg. different shades of green.

  I have had some success by adding the Fill effect to a layer,
  setting a suitable starting color, and then putting a wiggle expression on that color.

  This enables me to control the speed of change and limit the range of colours,
  but the colour changes smoothly and I want to create something that changes colour instantly.

  I have also tried using the random expression but can’t work out how to slow this down so it doesn’t change on every frame.

  Can anyone help?

  Thank you!

  wiggle (3,0.2) // causes colours to change gradually which I don't want

  and also tried

  random ([0,0.5,0,0.5]) // which causes erratic colour changes and I don't understand how to stop it changing on every frame

  Joey Harvey replied 12 years, 3 months ago 2 Members · 4 Replies
• 4 Replies

• 

  Dan Ebberts

  February 6, 2014 at 2:34 pm

  Something like this should slow things down:

  framesPerColor = 5;
  seg = Math.floor(timeToFrames(time)/framesPerColor);
  seedRandom(seg,true);
  value + [0,random(.5),0,0]

  Dan
• 

  Joey Harvey

  February 6, 2014 at 3:27 pm

  Lovely! That is great, thank you!

  In relation to this solution, would you be able to explain how the 4 digit color value is broken down? [0,0,0,0]

  My guess is that its something like [Red,Green,Blue,?] – is that right? If so, what is the value I have written as ‘?’
• 

  Dan Ebberts

  February 6, 2014 at 3:42 pm

  >what is the value I have written as ‘?’

  Alpha. Sometimes it isn’t used (as with the Fill effect), but it needs to be there.

  Dan
• 

  Joey Harvey

  February 6, 2014 at 4:26 pm

  Of course!

  That makes a lot of sense. Thank you very much for your time!

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