Dear Sandy,
That's the answer. Source forgotten, but obviously wrong. Thanks.
Cheers,
Roger
Roger,
To be fair, none of these processes are completely DOP or POP, in the sense that a modern bromide paper is DOP. Even with DOP kallitype and pt./pd. you have a whisper image that may impart some degree of self-masking, and with most POP processes there is some degree of intensification of the image in post-exposure wet processing.
That is why I used the term "primarily DOP" to describe true kallitype.
Sandy