Positive images while viewing negatives

[scott_kinkade]

Hey folks...

 

I was scanning some B&W medium format negatives last night and happened to hold

one strip in such a way that I had a very clear positive view of the images

contained on it. I was quite amazed and played around with it a bit, then went

about my work. A few minutes later I tried to duplicate the effect but

couldn't, and then later it happened again accidentally. The proper conditions

seemed to have something to do with the right combination of light reflected off

the emulsion (rather than the shinier non-emulsion side,) backlight (from my

light table,) and the black background formed by the frame of my light table.

 

Not only was this a startling and interesting effect, but it seemed very useful

as well, since I could literally see the positive image, which helped to pick

which frames I wanted to work with.

 

Questions: what is this effect called and how can I reliably duplicate it?

[nikos peri]

Have a bright light source on the (say) ceiling, shining down onto the negative emulsion side (matte side) held at 45 degrees to your line of sight. Don't know if it has a name, but it essentially is a reflected image instead of a transmitted one, where the greater densities (in the highlights) are more reflective than the lower densities (shadows) which allow the light straight through the negative instead of reflecting it to your eyes.

[nikos peri]

By the way, it helps to have a dark background behind your negative.

[pico_digoliardi]

It is easiest to observe with thin negatives and occurs because the background and film base transparency is close to the reflectivity of the image (the silver).

 

I find such negatives to be hard to print, unless the image is suitable (shooting on the toe), so they are the exception I'd avoid.

 

If you want something kinda sorta close on a print, look into the Sabatier Effect (solarization). It's still not quite the same.

 

You might also find similar effects on prints if you give them an inadequate fix (or better yet, just a good stop bath), and lay them out without any wash. It might take many days, but eventually with the right paper some of the image will stain to a glossy gold color and some of the image will partially reverse. (I learned this when friends pulled rejected exposure strips from my trash. Very cool to look at after thirty years.)

 

(If you want to try it in Photoshop, use the solarization effect on a duotone or tritone mode image.)

[scott_kinkade]

Thanks for the response.

 

Pico...what you say makes sense about difficult to print, as these pictures were shot in low light. In this case they weren't difficult to print because I expected a very dark image, but if they were exposed in daylight I'd definitely say something was wrong.

 

Cheers all.