I'm making a shader that combines two image textures based on the alpha channel of the texture on top.

Now I need a way to adjust and animate what comes from the alpha-output of the texture node and goes to the fac-input of the mix shader node. I need to make it fully transparent in the beginning and then slowly animate the opaque part in.

My problem is, the color nodes I've tried so far only seem to adjust RGB channels. Is there anything in the Cycles material nodes that can be used to adjust (and hopefully animate) the alpha output of a texture node?


1 Answer 1



The alpha channel is just another array of values, just like the R,G, and B channels, or any other grey, yellow, or purple socket.

So any node which manipulates values can be used to manipulate the alpha channel. For example:

enter image description here

Note the keyframed input in the math node. It's animated from 0 to 1.

Will result in:

  • 5
    $\begingroup$ To animate hover over the value you want to change and press I to create a key frame $\endgroup$
    – user1853
    Jan 22, 2015 at 23:48
  • 2
    $\begingroup$ @Antti If gandalf3 solved your problem you can click the “accept answer” checkmark on the side. $\endgroup$
    – PGmath
    Jan 23, 2015 at 15:08

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