MITRA Forum Question Details

Hello there,

​Pigments, unless exceptional, don't change colour to go darker over time. Binders however do yellow over time.

Your oil thus might, and depending on its chemistry can go quite dark as it oxidizes. I've seen poppy oils go dark as tea. If you're using wallnut, poppy, or other kind of exotic oils away from linseed and safflower, that's not impossible to get darker shade over time.

It's highly likely there is a misunderstanding in what's happening to your work. You may want to try oil colours from a different brand and compare.

Also expose your darkened pictures to sunlight for a while, it may bleach them back slightly to the expected early colour.

Cheers,

Lussh​

This is in response to Lussh's post of 2023-09-23:

The MITRA resources section has excellent information about the darkening of oils. Lussh, the way you have worded your response may inadvertently lead a reader to misinterpret your post. 

The darkening or yellowing of oils is understood by conservators. When you do not post the details of how and when you observed poppy oil to darken may lead a reader to assume that poppy oil routinely darkens more than linseed.  I do not think that walnut oil is exotic for oil painters. It has been used for hundreds of years.  

When you suggest exposing an oil painting to sunlight: do you mean direct sunlight? Direct sunlight has UV, which is known to damage oil paintings. Again, the MITRA resources explains this. 
​