# How to change material properties with time

I'm trying to create a magic halo behind an object. For this I decided (maybe, improperly - but I'm a newbie) to use hair. So I grew up a long hair, assigned an emissive material and made its colour change with location.

But now I also want that halo to gradually change colours as the time progresses. I cannot find any time-based shaders in the nodes collection, only as a composition node - but that one is to my understanding only applicable to the whole scene animation.

• This can be be done with keyframes. Almost all values in blender can be animated; to insert a keyframe, hover over the value you want to animate and press I. Then switch to a different frame, change the value, and insert another keyframe. The value will now change from the first value to the second over the course of the frames between the two keyframes. – gandalf3 Dec 12 '15 at 8:52
• But well, why can't I add a new keyframe? I tried adding the properties to a keying set, that went well, but adding a frame for that keying set produces "failed to insert any keyframes" error... Modifying the colours directly seems to produce a keyframe, but I can't see it on the timeline. – Mike Dec 12 '15 at 15:04
• Can you see the keyframes in the dopesheet? – gandalf3 Dec 12 '15 at 19:43
• Yes, thank you, I haven't seen this Dope Sheet before :-) Do you have any idea about the keying set problem? – Mike Dec 12 '15 at 20:36