"Merck's pyro has undergone a severe test in my hands. I find it to possess many qualities which give it superiority over all other makes. Authorities place the solubility of pyro as one part in two of water. I found one ounce of Merck's to dissolve readily in 1:7 of water at 60°. It is extremely light, pure, and of a fine white color, giving rich negatives full of vigor and sparkling brilliancy."
Walter E. Woodbury,
Editor of The Photographic Times.
"I have used Merck's Pyrogallic Acid, and prefer it to all others."
B. W. Kilburn,
Official Photographer (Stereoscopic), at the Columbian World's Fair, and San Francisco Mid-Winter Exposition.
"I have tried Merck's pyro and must certainly say it is the best I ever used. The results I have obtained with it are remarkably fine."
W. B. Post,
Amateur Photographer, New York.