Last week I was in London. I was there to discuss a set of designs we must prepare next autumn for windows we will make in 2016.

And so, leaving myself sufficient time between meetings, I called in to see a dear sculptor friend of mine.

He’s hugely talented. Famous too: successful. You’d probably recognise his name.

But despite his vast fame and talent, one look told me how upset he was. Anxious. Agitated.

“Me?”

He grabbed me in and straightways asked to model my head.

We are good friends, and I’ve a fine profile, but first I said: “Me?”

Then: “Why?”

And at last, when he’d told me, I said: “No!”

“No!”

Reason was not that I’m hard-hearted in the sense of being unhelpful.

To the contrary. Actually I was hard-hearted in order to be helpful.

You see the sculptor’s sculpture goes off for casting this next Thursday. (Why is there always this mad rush towards the end of a year?)

And the sculptor was worried about the head. Something wasn’t right, he said.

Which is where my head came in.

But I was having none of it.

And the reason I was having none of it is: because of what I know.

Outsiders always get this wrong

I know this from my own case. I know it’s true. I’d like to tell you because we glass painters are all just human after all. It’s this.

Just before we’re about to fit a window, we’re in a state of mad anxiety. It’s horrible, this worry. Truly horrible. Both of us here often feel sick to the very pit of our stomachs.

And outsiders always think we’re worried about the fitting: whether we’ve got the sizes right.

Sizes?

Oh, yes, there is that. Sizes are terribly important.

But you know we always measure carefully and several times. We also cut out paper templates. Sometimes we even made full-width prototypes and triple-check they go in smoothly.

But it’s not the sizes now.

It’s the light.

Anxiety about the light

You can never do a proper full-sized test for light, not for a set of 16 skylights, not for a triptych, not for a set of 12-feet windows which you see from 15-feet below. Of course you mount things on your blackened, towering, toughened easels. You squint at them from various angles. But whatever you do you can never replicate the final architecture: there can be no rehearsal here – apart from that solitary, frightful, passionate one you alone do in your imagination.

Is it too dark? Is it too light? Will the reds read as I want them to? Will the blues shine, or will they be dragged to grey?

And my point is: as professional glass painters, we just have to take hold of ourselves and not let the tension get the better of us.

You too. Yes. You just have to learn to live with the fact that – as time gets short  you’ll wonder if you’ve really done enough. Or done too much.

Shadows too dark here, highlights too bright there …

All the same, if you’ve honestly done everything you possibly can, then, at this point, you’ve just got to “run with” your own conviction and talent.

Up a mountain peak

Nothing arrogant here. It’s like you’re a skilful mountaineer, nearing the peak: no turning round now, and you must calm those nerves because nothing good can come of them.

There’s time for worry but it’s not now

Returning to my friend the famous sculptor: what could my head show him which might possibly soothe his worries about the head which he was working on?

Nothing.

The night before “opening night” is not the time to permit your worries to get out of hand.

Of course, if someone’s got no talent to start with, or they’ve not put in all the work that’s necessary to bring forth something magnificent, then worry is justified.

But not in my friend’s case.

A narrow escape

My sculptor friend was lucky it was me who visited him that day. A less stubborn person than I am might have acquiesced. A man-off-the-street might have jumped at this opportunity to have his features immortalised in bronze.

But I knew I was right to refuse.

My head – magnificent, if craggy – would only have added to the uncertainty.

I know this. You know this. You and I share this experience of looking at our painted glass just before it’s finished – and learning not to be too literal about what we see, summoning instead our imagination which already sees us on the peak. Because that is the only way to safely take the few last steps which must be made.