No consistent and true color film stock was available until the end of the 1940s, at which time Kodak introduced its Eastmancolor negative stock. With this product, a number of changes became possible in shooting technique, all of which decreased production cost and made spontaneity and mobility in shooting easier. Here the color was not printed in by dye-transfer, but was contained in an emulsion layer on the original negative stock in the form of dye couplers—chemicals that would be changed by the effect of color illumination. Eastmancolor prints were actually somewhat sharper than Technicolor prints, although the naked eye of the viewer did not detect this because of the "sharpening" effect of the color saturation of Technicolor. Cameras could now be considerably lighter and more mobile. Intense illumination was no longer required for shooting, and, in fact, it was possible to shoot color film in available light—as, famously, Néstor Almendros (1930–1992) did for Eric Rohmer (b. 1920) in Le Genou de Claire ( Claire's Knee , 1970); much of the extensive constraint as to costuming, makeup, set decoration, and lighting was removed. Unless it was exposed meticulously, however, and processed with great care, Eastmancolor gave inferior screen effects when compared with Technicolor. So poor were some of the results, owing to the money-saving casualness of treatment provided at the studios, that Kodak insisted the studios apply their own name to the process, and thus were born Pathécolor and WarnerColor. Most important for later film audiences, films shot in Eastmancolor (principally in the 1970s and onward) had a very short shelf life. Negatives were good for only around one hundred prints, and because these final prints were themselves degraded through projection their color was substantially lost. But the process was cheap, and thus attractive to producers who had to contend with higher above-the-line costs for stars and scripts. By contrast, the original Technicolor negatives were black and white and were used only for the production of the printing matrices. Thus, new Technicolor prints made from original negatives remain as crisp and brilliant as they were originally. DVDs printed from original Eastmancolor negatives make it possible to see films digitally that have, in their original form, hopelessly degraded.