THE DEFECTIVE PAINT!
This is a
serious warning about Aureolin
PY40 (Cobalt Yellow) in ALL brands. Despite the
ASTM ‘s good recommendation (rated ASTM II), my tests show that the pigment Aureolin PY40 turns
BROWN and FADES even in a dry state. I recommend that
you do not use this paint any more. The perfect substitute for
Aureolin is Winsor Lemon PY175.
sample [BELOW] shows how closely Winsor Lemon matches the color of
Aureolin- before Aureolin turned brown. Both samples were exposed to
exactly the same amount of light.
Aureolin (cobalt yellow) PY40
Winsor Lemon PY175
Aureolin, Cobalt yellow PY40.
was first sold as a paint in 1850. Winsor Lemon
was introduced in 1996
I had been aware of the defects
regarding Aureolin when researching my book "Color Right from the Start" in
1993. But because Aureolin-PY40 received an endorsement by the ASTM- the
American Society for Testing and Materials- as a recommended pigment I
felt that my research must be flawed and not the ASTM's! I reasoned
that perhaps my negative
results were due to the extreme heat or humidity in Texas for
instance? However, when testing Aureolin PY40 for my book
"Hilary Page's Guide to Watercolor Paints
and it's FREE online updates"
I found in ALL nine brands that use the pigment, that the
paint turned brown and faded.
I contacted the
chemists from two leading paint manufactures and told them of my
findings. They concurred with what I was saying- that Aureolin is a
defective pigment. One said that the pigment even turns brown in its
dry, powdered state! In addition the
pigment has a tendency to react with the medium in some brands,
causing the tube to explode. To crown it
all the paint is very expensive! We made a concerted effort to have
the ASTM re-test Aureolin. But to date this has not been done. It
should be noted that although the ASTM subcommittee that handles artists’
paints is manned by professionals in the field, they nevertheless
The actual color of Aureolin is
wonderful. As a "warm" lemon it is the color of the
standard primary yellow. This color is orange
biased at full strength meaning that it will mix with reds to
produce bright orange colors. It is green-biased in tint meaning
that it will produce fresh, vibrant greens when mixed with blues and
phthalo greens. Until recently there was no pigment available to
match Aureolin’s "warm" lemon, two-tone color qualities: PY3 Hansa Lemon is too
green biased and PY97 Hansa Yellow is a little too orange biased.
1996 a new pigment appeared in artists’
paints that is the perfect match for the "warm" lemon
color of Aureolin and it's cheaper too!. This pigment is PY175, a lemon Benzimidazolone as in WINSOR LEMON (Winsor & Newton).
The same color is in Cotman’s Lemon Yellow Hue PY175
or Permanent Yellow Lemon PY175
(MaimeriBlu) or (Schmincke's) Chrome Yellow Lemon (no lead) Any
paint made with PY138 is also the same "warm"
lemon color as Aureolin.
A few brands list an “Aureolin
Hue”. Usually it is
made with a warmer, more orange-biased yellow, PY97 or PY151. These
are not the best substitutes. They do not match the "warm"
lemon tone of Aureolin and so do not work so well in mixtures.. American
Journey’s "Aureolin" PY40, PY3 [BELOW] is a mixture
of both Aureolin Cobalt Yellow PY40 and the more stable, cheap
greenish lemon PY3. The bad news is that the paint contains enough
Cobalt Yellow for the pigment to react with the medium causing
the tube to almost explode! And it’s expensive too! Hansa
Lemon PY3 is too green biased to mix to produce bright oranges. The M Graham
& CO.brand has an Aureolin substitute (not shown)- but it is PY 97
(Hansa Yellow) It does not work in mixtures very well
to make greens.
American Journey’s"Aureolin" PY3,PY40
Hansa Yellow Lemon PY3
Without a doubt PY175 as in
Winsor Lemon is
the perfect substitute for Aureolin and cheaper too!