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Using After Effects expressions, I can create a color reference by pick-whipping a color control and the result is:

var rgb = rgbToHsl(effect("Color Control")("Color"));

But, I want to avoid using a color control, and simply instantiate a color through code:

var rgb = rgbToHsl([159,27,41,1]);

...but this doesn't seem to work. Is it possible?

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migrated from graphicdesign.stackexchange.com Nov 6 '13 at 18:08

This question came from our site for Graphic Design professionals, students, and enthusiasts.

2 Answers 2

up vote 1 down vote accepted

From what I'm reading, it looks like it may just be [R,G,B] where each value is a floating point number between 0 and 1. I'm looking in the Adobe After Effects Scripting Guide. Every method I can find that accepts a color value simply uses an array like that.

Update: While certain scripting methods take a 3 parameter RGB value, other expressions require RGBA or HSLA. In these cases, there will be a forth parameter for Alpha (ie, transparency) where 1 is fully opaque (a good default value) and 0 is fully transparent. If you get an error with one format, I suggest trying the other and if you get unexpected values, check if the input expects HSL or RGB.

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I believe it needs an array of 4, so you'd need to include the alpha value as well. Thanks for answering. –  itsmikem Nov 7 '13 at 19:27
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@itsmikem - for rgbToHsl it does appear it takes a rgba value, so if you need the color in hsla, then you would want to do 4 values with the final being the alpha. If you just want an RGB color, it only uses 3, but I'm not sure if rgbToHsl will work with that. –  AJ Henderson Nov 7 '13 at 19:52

Note: I'm new to this exchange, and I posted this to the graphic design exchange, but my question got migrated here. I thought it had been deleted, so I proceeded to post it on Creative Cow. I got a great answer there, and I'd like to give credit to Kevin Camp, who answered it perfectly:

your rgb values need to be in values 0-1 rather than 0-255. so if you want to stick with entering 0-255 values you just need to divide that array by 255...

var myColor = rgbToHsl([159,27,41,255]/255);

note, i did assume that you wante the alpha component to be full (255) not 1. if i guessed wrong, change the alpha back to 1.

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