We discovered a hand-painted professional oil colour chart which had been folded in storage for, we estimated, around five years. We found that the white swatches were visibly discoloured, ranging from light cream to yellow. It’s an example of dark yellowing, a reversible discolouration of oil paint that occurs when a painting is stored in the dark or in low-light. The phenomenon can affect oil paints of all qualities, from professional to student ranges and is most evident in white oil paints.
Artists and conservators have known about the phenomenon for centuries. In 1624, Rubens wrote a letter expressing his concern that a painting which was left in a packing case in Antwerp would go yellow in the dark. Rubens thought that this yellowing was caused by a surplus of oil leaching from the drying paint film, and while we know now that his interpretation is incorrect we still don’t know exactly what causes dark yellowing. What we do know is that it affects linseed oil much more than any other oil and that it is most likely to occur while the painting is drying. Of course, oil paints do not “dry” through the evaporation of water from the paint film, in the sense that water-based paints, such as acrylic or watercolour, do. “Drying oils” like linseed oil and safflower oil, are so-called because of their ability to react with oxygen from the air and polymerise into a solid paint film. Even if not much is known about the exact science of dark yellowing, we know that it is a consequence of this process of polymerisation.
Dark yellowing differs from age-related yellowing in that it is temporary and the discolouration should be reversed after exposure to light. To see this for ourselves, we covered half of each swatch and placed the colour chart in natural, but not direct, light. The exposed halves showed signs of losing their yellow hue very quickly and we noticed a change after just a couple of days. After a month, the swatches seemed to have recovered a good amount of their vibrancy, with the exception of Zinc White, which still looked a little warmer than it should be. However, the recovery is ongoing and the swatches will continue to adjust to the new light levels.
In all images, the left-hand side of the swatch shows dark yellowing, while the right-hand side shows the reversal of yellowing from the swatch having been exposed to ambient light for a month.
On our colour chart, paints with a linseed oil binder had yellowed the most as expected, but it was clear that the darkening varied depending on the pigment used- Titanium White with linseed oil had become cream while Zinc White with linseed oil had become a brighter yellow. The difference shows that the transparency of the pigment has an effect on the extent of yellowing- it must be remembered that the discolouration takes place in the binder, not in the pigment that is suspended in it. Zinc white pigment is semi-transparent, allowing the yellowing of the binder to be seen clearly. Titanium White is opaque enough to mask the discolouration of the linseed oil to a large extent and titanium white with safflower oil had barely changed at all, except that it appeared slightly warmer.

Titanium white with safflower oil, showing a barely perceptible amount of dark yellowing on the left
Although the effects of Dark Yellowing are reversible, it’s preferable to take steps to prevent it- if only to avoid the shock of finding that your painting looks very different to when you left it! While the painting is curing it will go yellow more quickly, so it’s particularly important that the painting is consistently exposed to normal amounts of light during this time. ‘Normal’ light can be ambient daylight as well as artificial light. It can take between six months and a year for a painting to cure but even after this time it is advisable to avoid storing paintings in the dark. Surfaces prepared with an oil-based primer can also be affected by dark yellowing and should receive adequate light.
Safflower oil is known to be a non-yellowing alternative to linseed oil. Our colour chart supports this, with Titanium White ground in safflower oil showing barely any yellowing at all. For this reason, some manufacturers use safflower oil to bind their white paints so you may choose to use these as alternatives to linseed oil-based whites. Safflower oil can also be used as a medium to extend the paint but bear in mind that safflower oil is much slower drying than linseed oil and forms a weaker paint film, so it is recommended to use it only in the final layers of a painting.
If dark yellowing has occurred, resist the temptation to put a painting in direct sunlight as it could cause fading in some pigments. Our advice is to give the painting the time it needs to adjust to normal lighting conditions.
Golden’s extensive research on dark yellowing was very helpful in the writing of this post. I highly recommend their blog post on the subject.
Thanks for this. I’ll go and unstack my paintings that are leaning against each other, particularly the one of icebergs!
No problem, Lesley! Glad to be of help
A great article on yellowing of oil
paintings kept in the dark. This is quite a
problem, as for many artists the only
option is to store paintings either in some
sort of covering or stacked so they are
effectively in the dark anyway, until they
get sold,.
Thanks for your comment Lenore- yes I agree, I think it’s also a key consideration for the buyer of the artwork to keep the painting looking its best.
It’s interesting to be given clarity
between what is age-related yellowing (
non reversible?) and a yellowing that
occurs during the ‘curing’. AND I know it
should be obvious – but to be told it isn’t
the pigment that yellows- it is the binder.
Do any whites go yellow with age?
Hello Frances, I’m glad the article was helpful to you! Age related yellowing of oil binders is, unfortunately, irreversible. Factors that contribute to age-related yellowing are numerous, complex and still a matter of debate among artists and conservators. The artist pigments themselves do not go yellow, but it is interesting to note that lead white pigments increase in transparency with age (There are examples of this in the National Gallery in London- passages of white which have become ghostly). If the pigment becomes more transparent with age, any yellowing of the binder will gradually become more obvious. Titanium White and Zinc White are not known to become more transparent over time, at least I haven’t come across any research which suggests so.
Very informative article.
Thank you very much, John!
Hi Evie,
I just bought a Mabef Pochade box.
What do you recommend to oil it with?
Thank you!
Hi Wendy, you can use linseed oil to condition and protect the wood. It’s best to rub it in with a cloth a little bit at a time.
Re darkening of whites. I use Griffin Alkyd oil paints and wonder
whether the Titanium white is affected?
What a great question. I’m unsure of how alkyd oils would be affected by dark yellowing. Let me do some research and get back to you!
Hello Maureen, a quick update! I did a very informal test with Griffin Alkyd oils- titanium white and zinc white- next to each other and let them dry in the dark (against the wall) both appear to have yellowed a little over two months (I am judging by eye, in comparison to the white of the canvas). The zinc white has yellowed more than the titanium white, which is what I expected. So in answer to your question- yes, Griffin Alkyd Oils do seem to be affected by dark yellowing, but no more than traditional oil paints.
I’ve just read your article as have
yellowing of titanium white of my
paintings done in artisan, water
mixable oils. Do you have any
knowledge of the same thing
happening in that type of paint? They
were stored on the top of a wardrobe
and not in the light at all. I will bring
them out and see what happens and
hope it works!
Hi Hannah,
It is very plausible that dark yellowing would also occur on watermixable oils, as these are made with a modified linseed oil, which is likely to possess the same properties as regular linseed oil. Have you noticed any changes to the appearance of the colour now you have brought it out into the light?
Many thanks
Lisa
Do Jackson’s oil paints contain linseed
or safflower?
Our Artist Oil paints are all bound with linseed oil. In our Professional Oil range we offer two titanium whites- one bound with linseed, and one with safflower.
How very interesting. I stack my
canvases as I’ve run out of wall space.
I’ll have to have a rehang so as not to
have a load of yellow paintings!
That sounds like a good idea! I’m glad the article interested you.
Thanks for the info very interesting and
helpful
I’m pleased it was helpful, thank you for the feedback!
Great comments on this informative
article. I have used oils, and alkyds for
many years and have always found that
applying a good quality gloss or matt
varnish really reduces any long term
yellowing of colours. Always making sure
that your paintings are totally dry,
especially oils, before varnishing. Even
very old paintings will benefit from a clean
and re-varnish.
Thank you for your comment, William! We always recommend using a removable varnish for exactly that reason. Removing and applying a fresh coat of varnish gives a new lease of life to an old oil painting, as well as being an important part of its conservation.
Thank you Evie… so I imagine that
whites that are less opaque in the nature
of their pigment ( Flake White for
example) are going to appear to yellow
more with age…that would go for all the
pigments with less in the way of tinting
strength?
Opacity of the pigment certainly plays a role in the degree of yellowing, but it’s worth remembering that tinting strength is not the same as opacity. Tinting strength refers to the strength of the pigment in mixes which is different to its opacity/transparency. Some pigments, like ultramarine blue, are transparent but have a high tinting strength. Due to its transparency, ultramarine blue develops a green undertone if the binder has yellowed. There are other factors which contribute to how yellow a colour appears, including the colour itself- a yellow paint would not noticeably be affected by dark yellowing, no matter how transparent the pigment. A transparent purple, being opposite to yellow on the colour wheel, would appear particularly muddy. I hope that helps!
Hi, really interesting, keep going!
Thanks Stella!
Hi, Evie, great article , big help , thanks.
What advise would you have for using
unfinished old painting? I often
incorporate the old image into my new
painting, concerned if over time, the old
paint can bleed through?
Hi, thank you for your question. The biggest consideration would be adhesion – we have a blog post about painting over an old oil painting which should help with this. Some pigments can become more translucent over time giving the impression that the old paint is bleeding through, but this is seen in paintings that are centuries old and this may or not be a concern for you. There is a great tradition of artists painting over and correcting older work! – https://www.nationalgallery.org.uk/paintings/glossary/pentimento
I have an oil painting with a light over to
illuminate the painting. Over many years
the painting has yellowed around the
upper center of the painting near the
light. This painting is over 100 years old.
Can this be fixed ?
Hi Daniel, I’d recommend speaking to a conservator about this to see what they advise!
Hi Daniel,
Without knowing the specific conditions of your painting it is hard to answer your question – has the painting faded or is it a victim of dark yellowing or some other temporary effect? You could try placing the work somewhere where lighting is even across the whole work and see if any changes appear in the colours on the top half of the painting, but this could take weeks or months. A much quicker solution may be to take it to a picture restorer and conservator who will be able to ascertain where the yellowing is temporary or permanent.
Many thanks
lisa
Thank you for this information. I made a test
with colour swatches of pure walnut oil and
safflower oil on white Paper (acid-free). I
was scared when I detected that my walnut
oil swatch got very yellow in the dark (within
three month), the safflower oil didn’t change
yet. My question is, do you think the
safflower oil will only take longer to yellow?
Hi Sabine! I’ve found that it’s not that safflower oil takes longer to yellow, but that it generally yellows less than linseed oil. But as a general rule the longer the oil paint swatch is in the dark, the more yellow it goes.
Sorry Evie for annoying again. It’s so
important for me.
Does dark yellowing stop sometime,
how long should I wate? I currently
make a test before going on using the
oil…
Stand oil starts to turn yellow now,
after some time (three month after
drying). I am very desperate because I
had hope that it would be stable. The
other swatches linseed and walnut did
yellow very soon after drying (one
month)
What about sunflower oil? Does it
yellow more or less than safflower oil?
Hi Sabine
Most of the dark yellowing occurs in the first year but it will continue to darken for many years if the painting is left in complete darkness.
But it can be reversed by unwrapping it and exposing it to light for a few days.
It is not a case of some linseed oils being “stable” or not. All white paints made with linseed oil will do this. But exposing the painting to normal light will reverse the ‘dark yellowing’. But it only yellows if the painting is in complete darkness for months or years. If paintings will be stored in a way that light cannot reach the surface, make sure they are taken out and exposed to light with plenty of time to recover before showing – a few days is often enough but it may take up to a month to fully reverse.
The fact that oil paint yellows over time, as it ages, is related to dark yellowing but it isn’t as big a colour change, and it cannot be reversed. Linseed oil is the strongest, most long-lasting oil paint binder and it also will yellow the most, because it’s the number of strong molecular bonds that causes the yellowing, so strength equals yellowing. But in well-made oil paint the yellowing is generally not very noticeable because it is masked by the pigment load. So except for white colours, yellowing isn’t a big concern unless you change the pigment concentration by adding anything which will dilute the concentration of pigment, allowing the yellowing to become noticeable. If what you add to dilute the pigment is more oil binder then it is even worse, because it also yellows. The yellowing of the oil binder is most noticeable in whites and blues, so it makes sense to use those colours bound with a less yellowing but weaker oil like poppy or safflower. Blockx oil colour uses poppy oil for its light colours, Sennelier uses safflower oil for all its colours, and many brands that use linseed for everything else will offer one titanium white made with safflower. Poppy oil yellows almost not at all but that is because it doesn’t have the strong bonds, so is a weaker surface (which means it can crack or be scratched).
Testing isolated oils for yellowing, without pigment, won’t give you the best idea of the yellowing of the paints.
Thank you very much Julie,
this explanation is really
helpful!
Many thanks
Sabine