<p>That comp links to a layer in a comp called &quot;Render Comp FHD&quot; that has an effect called &quot;Bg Color&quot;, which is most likely an expression colour control effect (found in <strong>effects&gt;expression controls</strong>, they do nothing, but can be used in expressions).</p>
<p>You can create an expression like this by <a href="https://helpx.adobe.com/after-effects/how-to/link-properties.html" rel="nofollow noreferrer">pick-whipping</a> to the effect in question. If it's in another comp you can open the effect controls window (<kbd>shift</kbd><kbd>ctl/⌘</kbd><kbd>t</kbd>) for the layer you want to be the controller, and click the padlock on the window tab. That will keep it open when you switch to the other comp, and you can drag the pick-whip to it.</p>
<p>Expressions reference here: <a href="https://ae-expressions.docsforadobe.dev/" rel="nofollow noreferrer">https://ae-expressions.docsforadobe.dev/</a></p>

CC BY-SA 4.0
2021-09-29T05:22:51.640Z
2021-09-29T05:22:51.640Z
stib
<p>I am a newbie in animation and I am learning by watching different projects.</p>
<p>And I found this expression, but I try to find information and I am not lucky.</p>
<pre><code>comp(&quot;Render Comp FHD&quot;).layer(&quot;Controls&quot;).effect(&quot;Bg Color&quot;)(&quot;ADBE Color Control-0001&quot;)
</code></pre>
<p>this expression is used to set the background color</p>
<p>Please I would like you to explain or give me links to deepen the subject</p>

CC BY-SA 4.0
2021-09-21T09:14:52.280Z
Can you share a link to where the expression came from?  You might need to provide more info about what the expression links to
tomh
<after-effects><after-effects-expressions>
Please someone explain this expression
m16u31
# Please someone explain this expression

(Asked by: username_0 on 2021-09-20)

I am a newbie in animation and I am learning by watching different projects.
And I found this expression, but I try to find information and I am not lucky.
comp("Render Comp FHD").layer("Controls").effect("Bg Color")("ADBE Color Control-0001")

this expression is used to set the background color
Please I would like you to explain or give me links to deepen the subject

**Tags:** after-effects, after-effects-expressions

> **Comments:**
> **username_1**: Can you share a link to where the expression came from?  You might need to provide more info about what the expression links to  

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## 1 answers

### Answer by username_2 on 2021-09-29. Score: 1

That comp links to a layer in a comp called "Render Comp FHD" that has an effect called "Bg Color", which is most likely an expression colour control effect (found in **effects>expression controls**, they do nothing, but can be used in expressions).

You can create an expression like this by [pick-whipping](https://helpx.adobe.com/after-effects/how-to/link-properties.html) to the effect in question. If it's in another comp you can open the effect controls window (`shift``ctl/⌘``t`) for the layer you want to be the controller, and click the padlock on the window tab. That will keep it open when you switch to the other comp, and you can drag the pick-whip to it.

Expressions reference here: <https://ae-expressions.docsforadobe.dev/>


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