</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (bmacphoto.com @ Nov 21 2002, 09:32 PM)</td></tr><tr><td id='QUOTE'>I could be totally wrong, but I believe that hardner wasn&#39;t added into fixer until the mid 60&#39;s.</td></tr></table><span id='postcolor'>
My 1943 copy of Kodak&#39;s "How to Make Good Pictures" lists only two fixers (F-5 and F-1), both with hardeners. The F-5 formula uses boric acid (like the modern F-5), and the F-1 (just sodium thiosulfate) had a hardening addition: either Kodak Liquid Hardener, or a sulfite/acetic acid/alum mixture.