A study of FujiFilm’s FM screening method TAFFETA

Sammanfattning: The study of Fujifilm´s halftoning method Taffeta has been done on behalf of Fujifilm Sverige AB, they especially wanted a subjective evaluation of Taffeta. Taffeta is a FM halftoning method of second generation, specific for this halftoning method is the structure of the dots, which should give a print with more evenness. Being present at the installation of Taffeta at Norrköpings Tryckeri gave a better understanding for the printing process and Taffeta. During the installation, the settings were done so the print with Taffeta is as similar it can be with print with AM halftoning method, in this way the printing company can use them both combined in print. Due to Fujifilm’s wishes, a subjective evaluation of Taffeta was set with highest priority. An objective evaluation was also performed, in this way there could be drawn parallels between this and the subjective evaluation. There are several parameters that can be studied in these two evaluations; we chose some of them that we found had importance in both visual opinion and when measuring the objective capacity of Taffeta. When decision was made of which parameters we should study a sheet, which should be used during the installation at Norrköpings Tryckeri, was produced. This sheet contained images to the subjective evaluation and areas that could be used in the objective evaluation. In the subjective evaluation a test panel was arranged, in this test panel it was eighteen persons present, these were divided into four groups dependent on experience from printing business. Parameters that were studied were; a general impression of the image, evenness, naturalness and sharpness in images. Persons in the test panel graded our five chosen images, printed with both AM halftoning method and Taffeta, in these five parameters. There was also a test where the persons compared the images, printed in AM and Taffeta, in this way we got a result which halftoning method that was found as better for each image. In the subjective evaluation we studied dot gain, gamut for prints and the amount of paint used in the halftoning methods. These evaluations has shown that print with AM halftoning method and Taffeta is found visual almost as same, but sharpness is much better reproduced with Taffeta according the test panel. Results from the subjective evaluation shows that the professional category does not distinguish much. Persons working with advertising and people that work in the printing industry found print with AM as better, while teacher at the university and students found print with Taffeta as better. In the objective evaluation the dot gain and the gamut for the prints with the two different halftoning methods did not distinguish, because the settings that was done at the installation. The amount print that is used in print is much less with Taffeta, 15% less than print with AM halftoning method. Strands Tryckeri, which has used Taffeta a longer time has established this.