By 1880 he had rented space in Rochester, had trained three assistants and had begun selling his plates to various black and white photographic supply houses. He kept his job at the bank, however, until 1881 when he went into partnership with Henry Strong, one of the roomers in his mother's boarding house, and formed the Eastman Dry Plate Company. Each man put up $1,000. But Eastman was aware that black and white photography would never become a popular hobby as long as black and white pictures were taken on awkward glass plates. What was needed was something light, inexpensive and flexible enough to put on rollers - in short, black and white film. His goal became obvious when the firm incorporated in 1884 under the name The Eastman Dry Plate and film Company. There was nothing new about the concept of roll black and white film. Almost from Daguerre's time, a number of men had tried with varying degrees of success to make it, but no one was able to produce it commercially until Eastman invented the equipment to manufacture black and white film on a mass basis. The result was Eastman's "American Black and white film," a roll of paper coated with a thin gelatin emulsion. After the black and white film was developed, the emulsion had to be stripped from the opaque paper backing to provide a negative that light could shine through for making black and white prints. Most black and white photographers had trouble with this operation-the negative often stretched when removed from the paper-so the black and white film was usually sent back to the company for processing. The new black and white film created a great stir among black and white photographers but it had little immediate meaning for the general public since the heavy, expensive view camera was still necessary to take black and white pictures. But roll black and white film made possible a new kind of camera - inexpensive, light and simple to operate - that made everyone a potential black and white photographer. In June 1888 Eastman introduced the Kodak. It came loaded with enough black and white film for 100 black and white pictures. When the roll was used up, the owner merely sent the camera with the exposed black and white film still in it back to the Eastman company in Rochester. Soon the developed and printed black and white photographs and the camera, reloaded with black and white film, were returned to the owner. The roll black and white film Kodak became an international sensation almost overnight. In the midst of all the excitement that followed the introduction of American Black and white film and the Kodak, few people paid any attention to a patent application filed in May 1887 by a New Jersey clergyman named Hannibal Goodwin. Yet Goodwin was the inventor of truly modern roll black and white film: a transparent flexible plastic coated with a thin emulsion and sturdy enough to be used without a paper support (as it is in most modern black and white films). Goodwin's starting point was a material developed in 1863 from the very substance that had served as the wet plate's emulsion base: collodion. Mixed with camphor, collodion became the versatile plastic, celluloid, which could be rolled, molded and extruded into many different forms and was used for handles on combs and brushes and for gentlemen's detachable collars. But commercially produced celluloid had severe shortcomings for Goodwin's purposes; it was not uniformly transparent and it became brittle after a short time. Goodwin modified celluloid with solvents and finally was able to produce this base at "two one-thousandths of an inch, more or less, in thickness." At first the black and white film tended to curl because the base was coated on only one side. Goodwin eliminated the problem by coating the other side with nonsensitized gelatin. But Goodwin's patent was not granted until September 1898, more than 11 years after he had made application. The reason for the delay was a condition common to parsons, a lack of funds. Goodwin could not afford to make tests the Patent Office required.