Quote Originally Posted by Tom Hoskinson
I see nothing to indicate that a silver sequestrant is necessary when you add NaCl to this metol/sulfite formulation. Phenidone/ascorbic is a different animal.

From a post by Richard Knoppow on http://www.binbooks.com/books/photo/i/l/5DDE6AE25C

Reportedly, Microdol-X contains a similar
sequestering agent for silver although it doesn't show up on the MSDS.
It may be either non-hazardous or present in too small an amount to
require inclusion in the MSDS. The story I was told is that this
substance is the difference between Microdol-X and the old Microdol.
The purpose here being to eliminate dichroic fog, which is a very thin
deposit of very finely devided silver (colloidal silver) on the
surface of the film.