Holographic Rainbow Reflective 3D Prints - 3D Printing on Diffraction Grating Sheets: A few years ago, I learned you could 3D print on a diffraction grating sheet and it will transfer the rainbow reflectiveness onto the print (the same as this chocolate). Like most things, I tried it out, had some luck and some failure, then moved on…

Seamless iridescent rainbow light pattern for print. High quality illustration. Swirly mix of pastel colors resembling holographic foil. Fantasy spect Stock Photo - Alamy

This Clever Trick Embeds Holographic Patterns In Your 3D Prints - Make

Waterproof Brand Logo Printed Metallic Foil Reflective Rainbow Eye Custom 3D Hologram Holographic Sticker - China Sticker and Custom Sticker price

3D Printer Filament, Color Change Rainbow PLA Filament 1.75 mm Dimensional Accuracy +/- 0.02 mm, 1 KG Spool, PLA Rainbow Multicolor : : Industrial & Scientific