While l was out fungi hunting today, found this one. I accidently knocked it and realised underneath is YELLOW! See the next 2 images.

When l said yellow, l meant YELLOW.

I realised that l could maybe use this fungi, when the yellow came off on my fingers.

So l got a piece of paper out of my bag and rubbed the fungi on the page....hey presto..yellow coloured paper. It was just like powdered paint. Going to experiment with it abit more later, when l have more time.