A printing system comprising: a print head array comprising a plurality of ink jet print heads for depositing a printing fluid onto a substrate to form images on the substrate; a first source adapted to emit UV radiation to polymerize the printing fluid deposited onto the substrate by the plurality of ink jet print heads to immobilize, but not cure, said printing fluid; and a mechanism adapted to adjust an energy level of the radiation emitted by said first source, wherein the fluid is selectively immobilized by said first source to exhibit a desired degree, or lack, of gloss; characterised in that the energy level shown in the "UVA mW/cm2" column of the following table results in the corresponding exhibited gloss levels in the "C", "M", "Y", "R", "G", "B" and "Avg" columns at 85 degrees for MCS, 3.1, and LED ink types and Hg and LED pinning lamps: Ink Type Pinning Lamps UVA mW/cm2 C M Y R G B Avg MCS Hg 27 95.1 96.3 94.1 39.5 8.5 91.2 70.8 MCS Hg 39 58.3 71.3 64.8 58.2 28.1 75.8 59.4 MCS Hg 65 15.3 18.2 15.2 13.7 10.4 15.4 14.7 MCS LED 5.8 91.5 98.4 97.2 63.9 57.7 91.4 83.4 MCS LED 24 50.7 55.8 97.3 62.4 41.4 67.4 62.5 MCS LED 36 30.9 29.0 73.3 35.5 42.0 30.1 40.1 3.1 Hg 27 79.1 72.3 91.4 89.4 94.6 88.1 85.8 3.1 Hg 39 35.5 36.1 46.1 49.8 49.3 49.9 44.5 3.1 Hg 65 13.9 14.0 15.2 11.7 12.0 12.5 13.2 3.1 LED 5.8 68.6 76.4 99.4 94.7 97.6 97.1 89.0 3.1 LED 24 43.6 37.8 98.6 55.3 72.5 36.1 57.3 3.1 LED 36 34.8 30.7 66.8 32.9 36.7 25.9 38.0 LED Hg 27 79.9 61.2 62.9 74.0 47.5 87.7 68.8 LED Hg 39 21.2 18.1 16.2 14.2 14.9 18.2 17.2 LED Hg 65 12.5 12.2 11.3 9.6 9.2 10.6 10.9 LED LED 5.8 76.1 66.4 96.0 63.3 76.1 74.7 75.4 LED LED 24 33.4 19.0 19.1 24.3 26.3 21.4 23.9 LED LED 36 20.9 17.1 15.0 18.8 18.7 17.5 18.0 a print head array comprising a plurality of ink jet print heads for depositing a printing fluid onto a substrate to form images on the substrate; a first source adapted to emit UV radiation to polymerize the printing fluid deposited onto the substrate by the plurality of ink jet print heads to immobilize, but not cure, said printing fluid; and a mechanism adapted to adjust an energy level of the radiation emitted by said first source, wherein the fluid is selectively immobilized by said first source to exhibit a desired degree, or lack, of gloss; characterised in that the energy level shown in the "UVA mW/cm2" column of the following table results in the corresponding exhibited gloss levels in the "C", "M", "Y", "R", "G", "B" and "Avg" columns at 85 degrees for MCS, 3.1, and LED ink types and Hg and LED pinning lamps: Ink Type Pinning Lamps UVA mW/cm2 C M Y R G B Avg MCS Hg 27 95.1 96.3 94.1 39.5 8.5 91.2 70.8 MCS Hg 39 58.3 71.3 64.8 58.2 28.1 75.8 59.4 MCS Hg 65 15.3 18.2 15.2 13.7 10.4 15.4 14.7 MCS LED 5.8 91.5 98.4 97.2 63.9 57.7 91.4 83.4 MCS LED 24 50.7 55.8 97.3 62.4 41.4 67.4 62.5 MCS LED 36 30.9 29.0 73.3 35.5 42.0 30.1 40.1 3.1 Hg 27 79.1 72.3 91.4 89.4 94.6 88.1 85.8 3.1 Hg 39 35.5 36.1 46.1 49.8 49.3 49.9 44.5 3.1 Hg 65 13.9 14.0 15.2 11.7 12.0 12.5 13.2 3.1 LED 5.8 68.6 76.4 99.4 94.7 97.6 97.1 89.0 3.1 LED 24 43.6 37.8 98.6 55.3 72.5 36.1 57.3 3.1 LED 36 34.8 30.7 66.8 32.9 36.7 25.9 38.0 LED Hg 27 79.9 61.2 62.9 74.0 47.5 87.7 68.8 LED Hg 39 21.2 18.1 16.2 14.2 14.9 18.2 17.2 LED Hg 65 12.5 12.2 11.3 9.6 9.2 10.6 10.9 LED LED 5.8 76.1 66.4 96.0 63.3 76.1 74.7 75.4 LED LED 24 33.4 19.0 19.1 24.3 26.3 21.4 23.9 LED LED 36 20.9 17.1 15.0 18.8 18.7 17.5 18.0