Reply To: Acid Test Pen, Folder test question


I have a groundwood  test pen purchased from Carr McLean (Canadian distributor for museum, archival and conservation supplies)  that has proven reliable as a general indicator of the presence or absence of groundwood pulp content in paper.  I also use the Abbey pH indicator pens and sometimes I have found if I have tested a number of acidic papers I sometimes get a false reading on an non-acidic paper.  My assumption is that the felt tip nib has picked up traces of acidity from the acidic papers and needs to be “wiped off” periodically to remove contamination