• Drawing

  Copper oxidation.

  Posted by tatiana on February 22, 2024 at 7:37 pm

  Member wrote:

  Regarding NP Traditional ground and copper’s tarnishing/ reaction. I have deliberately stayed away from copper after discovering drawings loosing 50 to 60 percent of their value on another commercially available acrylic ground. I am not the only one who has experienced this either. Is there any reason to suspect this may happen with the Natural Pigment ground? I have seen Nickel disappear overnight on day old casein white paint. Anyway, I suspect it is a chemical reaction that makes the copper metal more unstable with the acrylic polymer as a catalyst, maybe tarnishing to a yellow thus loosing value. Any insights?

  Answer:

  As it oxidizes, copper loses its initial tonal value (fades). Copper oxidation on different grounds will be different. Substances in acrylic dispersion grounds or other grounds may exacerbate oxidation and loss of value (fading). For example, casein grounds are typically made with alkalies that can induce these changes.

  tatiana replied 2 years, 1 month ago 1 Member · 0 Replies
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