I have noticed that if I hold my black and white negs at just the right angle to a light source that my eye sees the positive image as it would be on a proof sheet. Can someone explain this phenomenon to me and are people using this to evaluate their negs?

-m

-- Mike Howard (mikethoward@earthlink.net), September 07, 2001

Answers

It's simply that the dense part of the negative reflects light towards your eye while the clear part passes the light through (since there is no silver to reflect it). Thus, the image appears reversed.

I don't know of anyone who uses it for evaluation.

-- Charlie Strack (charlie_strack@sti.com), September 07, 2001.

This phenomenon is what made the Ambrotype of the mid nineteenth century work. A glass negative was mounted in contact with a black background causing the negative to appear as a positive.

-- Wayne Firth (wayne@silverlight.net), September 07, 2001.

Funny you should ask...I just started using Rodinal with Tri-X and noticed that the effect seems much more pronounced than it did with my prior developer. On most films the positive is much easier to see on exposures which are underexposed, usually enough underexposed to fall into the "ooops" category. I have found this type of viewing useful only on 35 mm where I have lots of photos of more or less the same thing (usually people) and I can look at the "positive" and tell which ones have decent facial expression and which don't. I've never been able to judge that just off the negative without taking advantage of this.

-- Kevin Crisp (KRCrisp@aol.com), September 07, 2001.

Well, I develop my fuji neopan 80 quickload positively using photochem black & white reversal kit. It is a great developer but you need a processor like jobo because you need to agitate continuosly, and also for repeatability. I find making a black and white positive better than printing a neg because it is much more consistent ie When I'm not around anymore the my images will accurately show what I wanted to show! I'm sure that EW would probably developed his films positively aswell if he could when he was around.

-- Renee Galang (r.galang@chisholm.vic.edu.au), September 07, 2001.