I've had a look at the tutorial and added remarks at the end of this answer because they are more related to the tutorial than to the Musgrave Texture node.
How to Colorize the Musgrave Texture
The Musgrave Texture node has a grey node output Height that outputs a single float number. The yellow color nodes work with an RGB tuple. And a purple vector node has 3 values, an XYZ tuple. Blender converts them automatically. Read here more about it: What is the meaning of the color of the node sockets in the node editor?
That been said, if you want to map the single float number to an RGB color tuple, you can use a Color Ramp node that represents the entire color spectrum.
To do this, set the Color Ramp node to
Far, and select the same color for the start and end. For example, make both red (hex
FF0000) and you will get all colors. The Musgrave texture output is colorized when you connect the nodes. The RGB color value then can be used for the XYZ vector input of the Voronoi texture for more modifications/randomness.
Remarks About the Tutorial
The tutorial uses an early experimental alpha version of Blender 2.8. I've downloaded Blender 2.80.74 (release candidate 1 of 3) which has the same Musgrave node but the output is still more blocky:
Node Changes and Adjustments for Blender 2.82+
To create this volumetric smoke animation in new Blender versions you need some adjustments:
- increase the strength of the Area light. Default is nowadays 10 W. That's not enough. It controls the brightness and the color. Try something between 300 W and 1000 W. The example is
- the Voronoi node has been changed. You need to square the Distance output with a Math node.
- the Musgrave Texture node has been changed. See above.
- to get a smoother render to decrease the Volumetrics > End value to
4 m in the Eevee Render Settings.
- the start/end color of the Color Ramp node for the Musgrave Texture node controls the amount of "Spaghetti" that you get, more black/dark or bright/white on the image that is. To be able to change the color conveniently use a Hue Saturation node and change the Hue value. This shifts the color palette. To do this easily by sliding the value with high precision there are the Math and Value nodes.
- decrease the Detail value of the Musgrave Texture node to make the fog/smoke smoother.
Make sure you are using Eevee and in Render view using scene light and scene world (black). Keyframe the X rotation of the Mapping node from 0° to 360° over 361 frames for a looped animation. That's the Ducky 3D tutorial.