Yellowing

[Levi van den Berg]

Hello this is my display cabinet I taped of the back and in the summer I keep my sure nu light falls on my models when the sun rises. I was wondering how fast yellowing can happen and of I have enough protection?

 

[Jakko]

Acrylic paints don’t yellow, a little research seems to tell me. Oil-based paints yellow because of the oil; as a British paint manufacturer puts it:

Paint “yellowing” on aging is a widely known and well documented characteristic property of alkyd (oil-based) enamels and is most noticeable in the dried films of pale coloured or white pigmented oilbased enamel paints or clear varnishes.

It has been extensively researched and is known to be due to the presence of chromophores (coloured chemicals) that are formed during the paints drying process. These chromophores are sensitive to light and will be bleached out of the paint film if exposed to daylight. Some alkyd enamel paints discolour more than others depending on the type of vegetable oil blend(eg. Safflower, sunflower, soya oil, etc) that is present in the formulation. However all alkyd enamel paints can be expected to develop a yellow tinge/tone as time passes, especially in the absence of daylight.

Oh, even better: you seem to be worried that the paint on your models will yellow because the sun shines on them in the morning. You may want to read this:

Of je nu een professionele of DHZ-verf koopt: alle verf op terpentinebasis vergeelt binnenshuis op plaatsen waar geen zonlicht bij komt.

(my emphasis)