Ever since I picked up a book on a Truffaut film called 'La nuit américaine' certain cowboy movies have been ruined for me. What is the 'American Night'? It's what they do in film making to pretend that a scene is at nght by using a dark filter over the lens. It is cheaper and less complex than really shooting at night. You can spot them easily enough because there are often shadows displayed, as if by very, very bright moonlight. They call it 'day for night' in English but obviously the French film industry picked it up from America and, in a sense, the meaning becomes 'Artificial Night'. Once you know this you can spot the effect in many films, particularly, I have found, in westerns from the fifties. Don't ask me why. Knowing this may well spoil your enjoyment of Randolph Scott films for ever. It is like watching a conjurer have cards fall from his sleeve in the middle of a trick.

That's what this is in the image. It is taken during the bright early morning, around nine thirty. Look at that shadow. You might think it is a spotlight causing it but no. That is my shadow cast by the sun. I put the photo together and then decided it wasn't so intriguing and messed about with hues and saturation and contrasts till I got this.

I was close to the obelisk - it is the Washington Monument in DC - and I elongated it hugely as it was also rather squat in the first version.

It can take on a host of new meanings with the title alone. Is this a metaphor for the 'American Night' we are now facing,? And is that an economic night or that dark tea time of the soul type of night? The threat of terrorism? Or is it a comment on the power and myth of monuments? Getting too deep for me.

Next week I hope to show more versions of the World War II Memorial done by invited guests.