Back to photography: Grevenmacher – Huelen Zant Brownprint Arches platine sensitizer formula by Christopher James, Alternative Photographic Processes, 2nd ed., p. 234 3 drops Tween 20 5% / 3 ml sensitizer (Note: without tween 20 the image is flat, grainy and lacks contrast) exposure 20″ Share this:TwitterFacebookLike this:Like Loading... Related