Hi John
>>Does anyone know what process would produce raised highlights, as opposed
to raised shadows?<<
Yes our old secrative friend the Fresson process.Although to be really
accurate you could also describe it as a process of sunken shadows with a
pigment less top coat of gelatin on the surface [ conjecture on my part].
Karl P Koenig's Gum/Oil process, and of course Photo/silk screen.
hopes this helps
pete