I've been watching Luminous Landscape Video Journal # 17, the interview with Jay Maisel. You could argue that a tour of his 'junk' collection is irrelevant but you get a strong sense of who the person is. Near the end of the interview they discuss having confidence in your work, the belief that you are better than most. Jay goes on to say that he feels photographers should be arrogant, they need to feel that when they show someone one of their images, the person will never quite look at the world the same way again.
I've written about emotional impact of images but I like this as a definition of a good image - one which will in some small way (or large) change the way the viewer will look at the world.
One might be excused for thinking this is pretty grandiose and impractical for all but a small minority of images, perhaps of famine or war or suffering, but what of a picture of a hand that makes the viewer look at his own hands the next time he's sitting on the can, perhaps turning his hands around, looking at the aging spots or wrinkles, the scars of a life times experience. Maybe it's one of my machine shop images which if I'm lucky will change the way a viewer looks at machinery in the future - as not just functional but as something with shape and curves and lines, something even to be enjoyed, perhaps touched or picked up instead of walking past.
Clearly not every photograph is going to to that for every viewer - it's clear from the images I have shown on this blog over the last couple of years that many images are only liked by some people. There are people who 'don't get' Pepper # 30, who cannot see beyond something that belongs in a salad.
So it would in fact be arrogance to believe that every one of my images (or yours) is going to affect every viewer, but the best of our images, for some of our viewers - yes I do believe we need that confidence or arrogance to feel we can change the viewer.