Cyanotype weirdness

[Liam Lawless <lawless@bulldoghome.com>]

Good Morning,

A cyanotype I'm working on is giving a kind of tone reversal that doesn't
seem like normal solarisation.  A picture of a black-skinned girl with long,
polished fingernails that show specular reflections - the reflections are
printing black whereas any sane person would expect them to print white...
or so I'd have thought.

On the positive these highlights measure 0% (Photoshop's eyedropper) and the
surrounding skin is about 40%; on the curved negative the reflections are
100% and their surroundings around 65%.  The rest of the image has printed
fine.  The reflections are relatively small, so I wonder if some kind of
'infectious development' is taking place.

Of course it's an easy matter to adjust the negative to avoid this problem,
but now I'm curious...


Thanks in advance,

Liam