Some call it photography without a camera, but really, it's merely using parts of the traditional photographic development process and making something really great. Pierre Cordier pioneered the chemigram over 50 years ago and when someone told him he should keep the process a secret for himself, he refused. Now the technique is an open-source phenomenon and even today, chemigram artists share their passion with each other online and otherwise.
Is there ever an exclusive technique? Is there any point in keeping it a secret? Cordier clearly thought it was not worth the price of taking his creation to the grave. Instead, he set forth a seed that has now grown to become a flourishing creative community.