My guess of what you're seeing is that the fixer is dissolving the white unexposed silver chloride under the negative (black/gray) image the developer creates. The white base of the unexposed silver chloride makes the image seem twice as dense by light passing through the image, to the white base, back through the image to your eye.
When making an (dry plate) ambryotype/tintype using Liquid Light, you'd need to use a unconventional developing agent that tints the exposed silver a color away from black, most commonly a ammonium thiocyanate is added to a developer to give the image a yellowish green/orange tint, or adding some amount of an exhausted rapid fix to the developer (ammonium thiosulfate). Ammonium gas does fume out when using these developers, so I've been trying (off and on) to use plain hypo (sodium thiosulfate) to achieve the same effect. Though I got the same color range as the ammonium, I have yet to achieve the reversal effect.
Also when the plate dries, the image will have less light blocking "power" because of gelatin's quality of contracting when it dries.
Last edited by musila; 10-07-2012 at 10:33 AM. Click to view previous post history.