Dare I blog this? It's the kind of self-exposure I didn't expect a blog – or a friend – to demand of me. Yesterday, Loretta nudged me into painting rather than writing at Middle Earth, and she's hard to resist.

Before I knew where I was, a page had been sliced from my pad of canvasses, a sketch of a frog was plopped in front of me, I'd taken a sponge, dipped it in dobs of green and white acrylic, and created a background. Loretta whisked this away to dry and handed me a pencil. “Now, sketch a frog. Copy that one”, indicating a pencil sketch in a copy of Artist's palette. I shuddered and obeyed. My attempts were all out of proportion and the toes were pointy. So I practised frog toes all over my piece of paper, gradually getting them rounded, although padded was beyond my skill. Soon the page was filled with disembodied feet, and a congregation of distorted frog-bodies.

My splotchy background reappeared in front of me, accompanied by a piece of chalk. This was beginning to look like commitment. My job now was to transfer the pencil distortions onto the painted surface. Chalk is a forgiving medium and I was content with the blurry white outlines on green.

But my task mistress wasn't. “Now you paint them, Meg.” I tried not to see painting as colouring in and to remember to hold my fine paintbrush side on: a darker green first, a bit of white for frog-forehead and frog-mouth, red for frog-eyes. A pause, and then a fiddle with yellow for frog-bellies. My mentor's comment? “You can only get better”!

When I returned home the strain showed. I was garaging the car, singing inanely “I'm a frog! I'm a frog! I'm a frog!” when I realised my next door neighbour was on the other side of the bushes.

As I reflected on my day, I was glad I'd been given frog as a subject. Now I have frogs on canvas, and their image can't be “truthed” because I never see them, although they've been in full voice in puddles and creeks as I walk around after rain.

And that was my first attempt at painting on canvas with acrylic. I'll take three weeks off now, to gather strength for the next phase.