Nanofiltration (NF) has attracted increasing interest for dye and NaCl fractionation in textile industry. However, it typically shows high rejections to divalent salts (i.e., Na2SO4), compromising to effectively purify dye from dye/Na2SO4 mixtures, which is crucial in digital ink-jet printing. This study used a tight ceramic ultrafiltration (UF) membrane (MWCO of 2410 Da) to desalinate diverse reactive dye species with molecular weights from 626.6 to 1205.4 Da. The UF membrane showed considerably high rejections to all the reactive dyes (> 98.12%) and nearly complete salt transmission (rejections < 0.1% and < 1.5% with 60 g L−1 NaCl and Na2SO4, respectively). Operational conditions, i.e., dye concentration, applied pressure and salt addition, have insignificant impacts on the dye rejection, due to dye aggregation. An integrated UF-diafiltration process, including pre-concentration, diafiltration and post-concentration, was designed to fractionate reactive dyes and Na2SO4. The model dye, reactive blue 19, can be concentrated to 142.60 g L−1 with a purity of 99.83% in the process, since low salt rejection and high dye retention of the membrane allows for 99.88% salt removal and 2.3% dye loss after ca. 9 diavolumes. These results indicate that tight ceramic UF membranes have high potential as a state-of-the-art technology in reactive dyes and Na2SO4 fractionation for digital ink-jet printing applications. Display omitted •Tight UF membrane is used in efficient dye purification for digital printing.•Tight UF membrane has consistently high rejection (> 98.12%) for 7 reactive dyes.•Integrated UF-diafiltration process removes 99.88% of Na2SO4 with ~9 diavolumes.•Reactive blue 19 is concentrated to 142.60 g L−1 with 99.83% purity in diafiltration.•Complete flux recovery for UF membrane is obtained after NaOH/HCl cleaning.