Next, we'll make keyframes for light color specifically, when in the Properties window using the following steps:
Move the current frame indicator to frame 1.
Select the lamp in 3D View with the RMB. Select the Object data button in the header of the Properties window. It's the button with the lamp, highlighted with the blue background in the following screenshot:
Down in the Lamp subpanel, there is the white Light Color box that you used in order to change the lamp color earlier. Move the cursor over that box and press I to insert a keyframe. There is no menu, but the white box gets a border. In Graph Editor, you now see a control curve for the lamp.
In Graph Editor, move the current frame indicator to frame
20.In the Lamp subpanel of the Properties window, use the color wheel to make the light a different color. The white box changes color. When you like the color, with the cursor over the box, press the I key to insert another keyframe. You will see...