If you have a serious interest in the mechanism of image formation, can I direct your attention to this weeks (12th September) issue of the British Journal of Photography?
The magazine carries a short, but information packed article by Dr. Andrew Stevens.
IMHO this article is of no small significance, but obviously has been greatly, and sadly overshadowed by the past week's tragic events in America.

The article describes research into detection of the photographic latent image by a technique known as electron-spin resonance (ESR). Briefly, ESR uses microwave radiation to stimulate the electrons of an atom into an excited state, which can then be detected by extremeley sensitive magnetic sensors called Superconducting Quantum Interference Devices (SQUIDs). The resonant frequency of an atom's electron cloud varies from element to element, and microwave radiation can be tuned to pick out individual atoms in a cluster of different materials. In this way, the tiny nano clusters of ionic silver, which form the pre-latent and latent image, can be detected within the silver-halide crystal lattice.

This research represents a significant breakthrough, since previous attempts to detect a latent image (other than development of course) have failed.
The data gained so far appear to confirm current theories about image formation, and this technique may provide a vital new tool for improving the sensitivity or processing of film emulsions.

Personally, I think this breakthrough may have come too late to revitalise silver halide imaging, but you never know!

-- Pete Andrews (p.l.andrews@bham.ac.uk), September 17, 2001

Answers

Fascinating! It is ironic that we are finally gaining some insight into the latent image now that silver imaging is almost obsolete. I'd like to read that article.

-- Ed Buffaloe (edb@unblinkingeye.com), September 17, 2001.

I'm interested, Pete. But I suspect there is no online version, is it?

-- Andrey Vorobyov (AndreyVorobyov@mail.ru), September 18, 2001.

Andrey: I've searched for any online papers on the subject without any success, so far. The BJP website also only has a limited number of technical articles archived there.
This may well be one that they decide to add at a future date. I hope so.

-- Pete Andrews (p.l.andrews@bham.ac.uk), September 18, 2001.