Dear MITRA administrators,
Last year (2022) was writen a study: New insights into the deterioration of TiO2 based oil paints: the effects of illumination conditions and surface interactions. [Thomas Schmitt et.al.] Full text available on https://heritagesciencejournal.springeropen.com/.
Conclusion states “Both anatase and rutile TiO2 based samples showed these characteristic markers of degradation under the visible and UV–vis light conditions used in these experiments. By measuring the change in intensity of characteristic degradation FT-IR peaks, we showed that anatase and rutile based paints facilitate similar rates of linseed oil degradation.”
Also, they explicitly wrote that coated TiO2 was not used in this study. [First passage under “Materials and methods”.]
Based on all above, what do you suggest, to use it or maybe not in oil paint?
Kind Regards,
Damir Pusic.
Hello Damir,
It’s technically correct, both these structures of TiO2 have photocatalytic activity (with slightly different band gap). It’s a technology used to clean water for instance, by easing the oxydation of everything organic under the right light over pannels with these untreated crystals.
However as Greg mentions, commercially used TiO2 as a pigment is nearly exclusively surface treated to avoid that ‘chalking’ defect and ease dispersion.
Also it’s not specific to oils. That is true in any media. I’ve mostly seen that in cheap acrylic wall paints.
And as far as opaque white pigments go, I think we should keep using it in oil and everywhere else personally.
Cheers,
Lussh
Uncoated TiO2 is known to be photocatalytic, with anatase being much more so. The TiO2 used by many manufacturers has a surface treatment, so the results of this test are not really comparable to current products. We would hope the authors continue their research adding coated TiO2 data.
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