I respectfully disagree (I'm not really a fan of "reading between the lines"). The Talbot Museum at Lacock Abbey would disagree with this interpretation also.
Originally Posted by cliveh
My understanding (and of course my notes are packed in preparation for a move) was that he used the salt fixing more for his photogenic drawings and not so much for the prints from his calotype negatives. I'm also aware that much of the color difference in prints had lot to do with the sizing used in the different papers of the day (i.e., one color from arrowroot sized paper and another from gelatin sized paper). Also keep in mind, he improved his process many times before he was satisfied. His original photogenic drawings are very different from the salt prints he did later (the processes are related but not the same). The aesthetic value of a given print was always a bit secondary to permanence.
Post-Talbot workers almost always use(d) plain hypo for their salt prints.