When I worked at a print shop, we had to calibrate the copiers every morning. It involved printing out a scale of colors and using a device that determined whether a color was correct. Before the device, we did it manually, for the blacks. For the colors, the copiers printed several sheets that we then put through the copiers scanner, which calibrated. There were deviations rarely.

Edit: clarified a few things, now that I thought about it.

The Romans figured that out?

One of his buttons is a QR code.

That's a lotta green.

This better not awaken anything in me.

I work for a huge printing company and normally when onboarding a new brand or processing tests for product changes we will get whole books full of these.

We also have a large library of images put together by the Devs of holidays, weddings, days out etc. to provide a little more variation in our tests.

I always think they look like Pokémon gym leaders whenever I print these at work

Love the pike. Clearly it's essential for print quality evaluation.