Foxing on your artwork


If you collect watercolour paintings or works on paper, you may be familiar with the appearance of reddish-brown spots, commonly known as ‘foxing’. Rusty looking spots mar the appeal of your painting, and if left untreated, can cause severe damage to an already delicate artwork.

What causes Foxing

Reversing and restoring the surface pigments of most original prints of Mould damage and foxing spots is achievable.

Firstly, Fungal growth on paper causes Foxing is one theory. Another possible cause is the oxidation of iron, copper, or other substances in the pulp or rag papers from where the paper was made. High humidity may contribute to Foxing.

At the heart of all foxing instances, you’ll find mould spores needing suitable conditions to thrive. 

As the paper degrades, becoming more acidic and more absorbent as sizing agents break down. Paper reaches a certain acidity level, combines with humidity in the atmosphere, causing impurities and mould to grow; the reddish stains then appear.

Furthermore, Foxing causes your artwork to be unusually eye-catching for the wrong reasons. Subtle colours and shades used in works-on-paper are at odds with the unmistakable bold reddish-brown impressions on the painting. 

How Foxing affects your artwork

With artwork where there is possibly an expanse of cloud or a stretch of sea, it’s very noticeable. You can see from the image, these marks mottle and blemish the artwork.

Foxing is treated without compromising the paper support or pigments. Also, and to a certain extent, you can treat it using specific washing treatments that flush out the paper’s polluted acidic elements. However, usually, removing foxing use a conservation standard bleaching agent.

Many issues arise with watercolours and works on paper; Foxing is preventable. Paper consistently absorbs moisture from the atmosphere, therefore absorbing many impurities. It’s sensible to put preventative measures in place and avoid future damage. Ensure your painting is correctly stored and displayed, with minimal exposure to humidity.

Frame your artwork with Tru Vue Museum Glass®, preventing 99% of UV light, is often another favourable option.

Important to realize, we often work with artwork restoration and conservation specialists. Contact us for assistance.

2 thoughts on “Foxing on your artwork

  1. Stephen Siddons says:

    Are you still in business. I have a one off pencil drawing by Christopher J May, it has developed brown spots on the white paper backround. Any suggestions on what you can do please ?

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