Blue Print

By Tanja Pelzmann and Maharaj Tegan,
PhD candidates at Polytechnique School of Montreal

Dyes have been an important part of art and science for a very long time. We use colours to convey feelings, label diagrams; to tint paint that will coat buildings, toys, and many other objects. Ever since we have represented things by pictures, from early cave paintings to art, architectural blueprints, whiteboard markers it has always been useful to convey different information by making things differently coloured. An important aspect of conveying this information is the “colourfastness” of a dye - how long a material tinted with the dye will hold its colour over time. Other important aspects include the safety (of contact or consumption) of the dye and its impact on the environment, as well as the properties of the dye that might make it desirable for other reasons - e.g. in pottery glazes, there are dyes which make the material stronger when it has been fired; in paint, some dyes could absorb or reflect desirable spectra; in medical imaging the dye could be easily attached to a certain protein, etc. Blue dyes in particular have an interesting history. Partly because of the short wavelength of blue light, it has historically been difficult to find substances which reflect blue light and are chemically stable. There are very few plant-based sources of blue dye, and most of these (e.g. woad) require a lot of raw product to produce a small amount of dye [2]. During the Renaissance, ultramarine blue was the most expensive paint colour [5]. The recent discovery of a new blue dye is an interesting story in innovation - a lot of hard work, a bit of luck, and something useful results which is not necessarily what we expected.

A Serendipitous Accident

What has happened in the laboratories of the chemistry department of the Oregon State University (OSU) can be seen as a prime example of pure serendipity. It was not the lucky accident that it is worth to be emphasized here, but the intelligent conclusion derived by the attentive discovered from its pleasant surprise.

In 2009, graduate student Andrew Smith put his manganese oxide samples in the furnace at around 1200 °C as usual to investigate their electronic properties. When he lifted the lid, he found his specimen had changed their colour from black towards a brilliant blue. His professor, Mas Subramanian, who had worked some years in industry linked to chemistry, immediately saw the potential of this finding. He was aware of the fact that high quality blue colour pigments remain a challenge for the industry up to now, since they are often not stable, toxic or easily dissolve [3]. The underlying crystal structure formed by Manganese, Yttrium and Indium at such high temperatures signalled to Subramanian that this colour pigment has to be a very stable one. It exhibits absorption of red and green light and a high reflectivity of blue. It does not disperse in water or oil, and the physical properties prevent the colour from fading. In an interview Subramanian said that It was serendipity, actually; a happy, accidental discovery, but then he admitted, If I hadn’t come from an industry research background DuPont has a division that developed pigments and obviously they are used in paint and many other things I would not have known this was highly unusual, a discovery with strong commercial potential.[1]

Applications beyond blue

Further investigations of the colour properties showed that it absorbs UV and reflects IR radiation, meaning that such a painting will prevent the underlying structure from being heated up by reflecting the heat [4]. This cool colour offers thus a range of application in the field of energy efficiency. But also in the more obvious application in art, the new blue shows vast potential. Its fade-resistance makes it an ideal candidate for restoring old paintings and the intensity of the colour can be adjusted by playing with the ratio between Manganese and Indium. The OSU chemistry department holds since 2012 a patent on the colour which is now officially referred to as YInMn Blue (or MasBlue at OSU). The new blue has meanwhile been adopted in Forbes Pigment Collection and the Havard Art Museum. A few artists already use the colour, and the Shepherd Color company already saved their right for commercialization. Mas Subramanian and his team inspired by their findings continue their scientific journey on the colour palette on the search of new safe, stable and brilliant colours.

Conclusion

This story illustrates the process of innovation - beginning with some knowledge, we build on that knowledge, perform experiments, think about the results, and try new things an innovation does not necessarily mean that someone set out in advance to discover some specific thing. In the case of the Oregon State University lab, we can see that Mas Subramanian and his team were acting as true innovators - studying the efficiencies of electrically conducting substances, they stumbled on something unexpected and analyzed their findings in a novel way. This led to the creation of something they were not looking for in the first place - a remarkably stable, colourfast, and safe blue dye.


References

[1] Mark Floyd. Licensing agreement reached on brilliant new blue pigment discovered by happy accident. 2015. URL: http://oregonstate.edu/ua/ncs/archives/2015/may/licensing-agreement-reached-brilliant-new-blue-pigment-discovered-happy-accident.

[2] Julia McLean. Paint it Blue. Sept. 2012. url: http://lifeasahuman.com/2011/arts-culture/culture/paint-it-blue.

[3] Department of Chemistry Oregon State University. The Story of YInMn Blue. Url: http://chemistry.oregonstate.edu/content/story-yinmn-blue.

[4] Andrew E Smith, Matthew C Comstock, and MA Subramanian. “Spectral proper-ties of the UV absorbing and near-IR reflecting blue pigment, YIn 1-x Mn x O 3”. In: Dyes and Pigments 133 (2016), pp. 214–221.

[5] Ultramarine. Encyclopaedia Britannica. 11th ed. Cambridge University Press, 1999.