Measurement of chromium content in dichromated gelatin by x-ray fluorescence

X-ray fluorescence was applied to the determination of the chromium-ion content in developed dichromated gelatin after exposure. It was found that the Cr(3+) ions irreversibly linked to the gelatin molecules do not exceed one half of the original concentration of the ions. A similar study was carried out on the hardening of dichromated gelatin during dark reaction: as long as the degree of hardening of the gelatin allowed the chromium ions to migrate out of the film during development, the final Cr(3+) content was less than or equal to one half the original concentration.