A good idea when using markers is to fill in a sheet of paper with examples of the colours available to you, because that's the only way you can be certain what the colour inside the pen will actually look like. Supposedly...

Look at the box labelled V04. That's a patch I coloured not long after I got that pen, a year or two ago. It's very bright - in fact, so bright it doesn't really fit in with the other shades in that series. Damn. Oh well.

But now, on the right of it is a sample, using the exact same pen, that I coloured a little earlier today. What the hell happened, pen? When did you decide to start being sensible? You've made my samples page invalid, now!

It doesn't even appear to be some kind of reaction to the paper. I scribbled the same pen in a corner of that page looks the same as it does on the piece of scrap. Crazy.