CARDBOARD PRODUCTS-NAMELY, PICTURE MAT BOARD, MOUNTING BOARD, WOOD PULP BOARD FOR PICTURE MOUNTING, ADVERTISING DISPLAY BLANKS, SHOWCARD BOARD, BOARD FOR USE WITH SILK SCREEN PROCESS PRINTING, ARTISTS' BRISTOL BOARD, [ MENU COVER BOARD, CARDBOARD PANELS HAVING ONE CANVAS SURFACE FOR ARTISTS' PAINTINGS, CARDBOARD SUPPORTS FOR DISPLAY CARDS, ] AND MOUNTINGS FOR PHOTOGRAPHS