Thanks, Mark. I’ll have a look at this.

Yes on the surface it seems somewhat counterintuitive that scattering effects result in increased overall contrast when the light source is collimated. This is reflected in the formula for the Callier Q factor, which for a given amount of developed silver is the attenuation of collimated light divided by the attenuation of diffuse light, and the Q factor is always >=1. Some diagrams could help here but I’m stuck at work late…

Quote Originally Posted by Mark J View Post
I can't see how you can increase the contrast ( with a fixed light source colour/grade ) from a contact print situation, by going to any form of enlargement. Contact printing pretty much has the maximum directionality of the light reaching the negative - because it is illuminated by a small distant lens pupil that might be 2 or 3 feet above the neg.

There is a thread here in the UK where I showed how i worked through my thoughts on this.

This is where I joined, but I was late to the party -
http://www.film-and-darkroom-user.or...t=14020&page=6

There are print scans near the end.