I found this really easy tutorial for How to Make a Rainbow Brush on YouTube by RXDIXNCE. Please support this artist by subscribing to Rxdixnce’s YouTube channel.

Below I have written out step by step instructions for creating a Rainbow Brush. You can use this on different Brushes, not just the 6B Pencil.

Step by Step Instruction: Making a Procreate Rainbow Brush

Go into the Brush Library.

Choose a Brush.

Slide it to the left and duplicate the Brush.

Open the Brush Studio by clicking on the Brush.

Click on Color Dynamics.

Go to Stamp Color Jitter, move the saturation to 80%

Next go to Color Pressure and move Hue to the max. Move Saturation to 60%

Next go to Color Tilt and move Hue to Max and Saturation to Max.

Then within the Brush Studio, in the Settings column choose Apple Pencil. In the Pressure column, move Flow to 0%

Test out your New Rainbow Brush on the Drawing Pad. Make any adjustments you would like.

Once you are finished, click the Done button and use your New Rainbow Brush.

Resources:

Easy tutorial for How to Make a Rainbow Brush found on YouTube by RXDIXNCE.

Kymberli's Art Blog art class Procreate