In order to maintain the photographic image qualities of graphic arts films, chemical analysis of both stock solution and tank solution of automatic processing machine are quite important. The methods to determine the constituents of Kodak developer D-85b (for graphic arts films) in stock solutions are studied in the condition of separate solutions A and B. The constituents of A solution are easily determined by the conventional methods already reported. The constituents in question are paraformaldehyde and formaldehyde-sodium-bisulfite, and both can be determined by the comparatively simple volumetric titrations. Namely, paraformaldehyde is determined from sodium hydroxide, which is produced by the addition of excess sodium sulfite, by alkalimetric titration with standard hydrochloric acid solution. Formaldehyde-sodium-bisulfite, formed by the combination of paraformaldehyde and sulfite, is decomposed to formaldehyde and sulfite by the addition of sodium carbonate, and then sulfite can be titrated with standard iodine solution, using starch indicator.