This workflow lets you create a custom color in your specular highlights! I made a rainbow, but you can put any color in it. Below see the links to reference materials on thin-film interference, and dot product! (Note: I added a BONUS effect at 9min)
Oil Rainbow Effect Article: (ooooh....SCIENCE!)
https://petroleumservicecompany.com/b...
Get Dot Product: • WTF Is? Get DOT Product To in Unreal ...
Multi Material-Masking Tutorial:
• Gold Cloth Material ...Instance Unreal
Download Rainbow Texture & Scratches Normal Map
https://drive.google.com/drive/folder...
Do you also want the CD-ROM? (let me know)
NOTE: Cassette version, not available ;-)