Zinc Oxide makes dried oil paint brittle (prone to cracking) and can cause the paint to delaminate (peel off). There is a ton of research available about the downsides to zinc oxide, but one of the best articles I’ve read is found on JustPaint.org.
A zinc/titanium white mix is popular among landscape painters because zinc white remains brighter over time. You just need to decide if that extra bit of brightness is worth the risk.
Clove oil is fantastic for slowing down the oxidation (drying) of oil paints. I’ve been experimenting with clove oil and a palette cover to slow down the drying of the paints on my palette.
Avoid mixing the clove oil directly into your paint. Clove oil softens the final paint film and leaves it susceptible to damage – just ask conservators who’ve worked with paintings where clove oil was mixed into the paint. The softer ‘skin’ allows dirt and pollutants to embed more easily into the paint and the gentlest cleaning agents can damage the paintings.
That’s what happens with water-mixable oils as well. The paint dries slower and softer than traditional oil paint.
Artists have experimented with lots of solvents. Solvents evaporate and leave little behind. Oils on the other hand oxidize and form a tough shell to protect and bind the pigment (color) to the painting surface.
Artists use solvents such as Turpentine, Mineral Spirits, and Spike Oil to add fluidity to their paints or to create watercolor type washes that they can easily cover their canvases with. The solvent evaporates (dries) quickly (within minutes) and can then be painted over without fear of substantially altering the initial wash.
The main problem with solvents is that the evaporative nature and the aromatics are generally toxic and over time can cause severe health problems for artists. Turpentine is one of the worst. The toxicity of Spike oil (lavender) is mostly unknown – no real studies have been conducted. My own experience is that it caused me to feel flushed. Because of that, I stopped using it. It smells great (if you’re a fan of lavender), but the smell is powerful.
Mineral spirits (especially Gamsol) are the least toxic since they’ve removed 99% of the aromatics. Even so, it’s still toxic. I used it for almost 30 years without noticeable negative effects which seem to be the case with many artists, but other artists have developed strong allergic reactions over time. I decided to stop using it about 10 years ago just to avoid potential problems.
The other downside is that we artists think we can mix a watery soup, and everything will be grand. All solvents, including mineral spirits, weaken the paint film – they thin the binder (oil). Too much solvent will effectively remove the binder and leave the pigment to flake off the painting. So, if you use solvent, use it sparingly.
What art materials do you avoid?
Stay Healthy and Happy painting!