Over 30 white and coloured titanium enamels of different origin were tested with a derivatograph. Thermoceram crucibles were used, which enabled the tests to be interrupted when a change was indicated by the DTA curve. The crucible was removed from the derivatograph, and the sample pulverized and studied by X-ray diffraction method. A major difference compared to previous observations was the fact that the exothermic peak indicating the anatase-rutile transformation was also found on the DTA curves of certain anatase-type enamels. With these enamels the temperature relating to the start of the transformation peak was regarded as the critical temperature, as at a temperature below this the enamel was stable, but above it unstable.