This week I made holographic chocolate. It looks like this:

You make it by pouring melted chocolate onto a diffraction grid. I got this one from eBay. It looks like this:

Some chocolate on a diffraction grid, the grid is reflecting rainbows

One interesting wrinkle is that the chocolate has to be tempered to work. I tried without tempering the chocolate and it came out with just a shiny surface.

I have NO idea why the chocolate needs to be tempered (or if something else actually made the difference. I’ve asked at Seasoned Advice and look forward to any bright ideas.

Other note - the effect vanished with a few minutes - I’m assuming because chocolate is quite a delicate material to maintain the tiny tiny tiny ridges that the effect needs, and the combination of air movement and condensation (I didn’t give it a chance to warm up to room temp before taking the film (mould?) off).