Light pad — what is it?

I bought an interesting gadget from the Chinese — a light pad. It's used to copy something from one sheet onto another. This is a very budget A4 model; it has 3 brightness settings. The most convenient thing is that it works perfectly from a power bank. There are also more expensive models from well-known art-supply manufacturers. They are, of course, much higher quality, without that pixel grid. But I decided I didn't need that; the simplest and cheapest model is enough for me.

What I use it for is transferring outlines from a pencil sketch to a new sheet. I do this for watercolor and marker drawings. For marker work this is a very important step, because graphite dust ruins felt nibs. For watercolor it's worth doing if the sketch has been corrected many times or if the paper is damaged by pencil or eraser. Dirt easily builds up on such paper. Besides, it's useful if you want to make the same illustration in different techniques or color variations.