Maybe it used to be… go back in time five years or so, before photo printers were invented, your average everyday inkjet printer would just have used black ink. The printer was a lot like your fax machine – used to print off text pages and maybe a limited graphic. So before the advent of photo printer’s people’s expectations of their desk top printer was fairly simple: does it pick up paper, without screwing it up; is the text legible; does it dry quickly without smudging.

Moving forward now to the present day and because cheap printer’s aren’t renowned for their longevity and that they don’t cost a king’s ransom (loads of Lexmark one’s are free with a new computer) – loads of people have got a printer which is also a photo processing unit, which they expect to produce better results than Max Spielmann’s! So if the ink used in these new photo processing units was just ‘coloured water’ how would the user feel if they spent good time and money on glossy paper and the prints were just washed out and faded before you placed them into the photo album?

To cut a long story short, the technology used in ink is amazing, it just has to be.. otherwise imagine the force of complaints from all the users. The major inkjet companies either employ or outsource hundreds and scientists to invent and test only the best ink for use in their printers. In fact it is a rumour that HP has a group of 16 scientists based in South America (location unknown/secret) whose sole purpose is to test recycled cartridges and their ink to see if they infringe their own ink’s patents/copyrights. HP have actually won some cases against a few large companies who have re-filled cartridges with ink that has infringed their intellectual property. How the infringement is determined is beyond this blog, but suffice to say that the ink used in these recycled HP cartridges must be damn close to the original stuff.

Also, what this suggests to me is that Hewlett Packard must be are worried that the re-cyclers are getting close to achieving similar results to their own original cartridges. I have seen the printed results from recycled cartridges being just as good as the original’s and I have also seen awful results that have white lines across the page and either pink or green hue throughout the printout. The end quality of the print-out is a result of many things – but the main one’s being the recycling process and importantly the quality of the ink used to re-fill them.

Anyway back to the point, just a few qualities that the ink must have these days are:-
> Fade resistance or colourfastness
> Have correct colouring – pigmented or dye based
> Be smudge resistant
> Fast drying
> Remain uniform in colour through time i.e. keep the colour and solvent mixed in the same proportion from the first print to the last one
> Have the correct viscosity, PH level and surface tension

Add to this all the complexities involved with how the different ink interact with each other, the paper and the outer environment and you can see that even though ink makes up around 80% of the ink it is not just colour water. A more detailed report on inkjet ink can be read here.