Dyeing cellulosic fibres with reactive dyes wastes great quantities of salt and water. The objective of this work is to dye cellulosic fibers using colored nanoparticles (CNPs) as an alternative to dyeing with reactive dyes, without salt and without washing off at the end of dyeing. Samples of cotton were dyed by exhaustion with CNPs at medium to dark colours. Build-up of colour compared to samples from previous work is given and shows a big improvement. Washfastness results are given. Washing-off after dyeing was not necessary for the red and yellow colours. The blue colour needs some washing off since the fastness is lower than for the other colours even though soaping is not necessary, saving energy and time relative to dyeing with reactive dyes.