Pigments No.1
The Color Index
Before beginning this chapter on pigments, it can be useful to
say something about the international nomenclature of pigments: the
Color Index. Each pigment has received a Color Index
Number (C.I.#), which is made up of letters and digits like
this:
| PB15: |
PB = Pigment Blue |
15 = identifying number for Phthalocyanine Blue |
| PBk11: |
PBk = Pigment Black |
11 = identifying number for Mars Black |
The complete system is:
| PB = Pigment Blue |
PBk = Pigment Black |
| PBr = Pigment Brown |
PG = Pigment Green |
| PO = Pigment Orange |
PR = Pigment Red |
| PV = Pigment Violet |
PW = Pigment White |
| PY = Pigment Yellow |
|
This system is far from being perfect —
for example, PBr7 can represent 3 or 4 different earth pigments
(see The Iron Oxides).
Nevertheless, it is a useful tool for the artist who wants to kwow
more precisely which pigments hide behind traditional color names
like e.g. Naples Yellow, Hooker´s Green or Bright Red.
Actually, the composition of such colors can vary among
manufacturers.
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(Back to History of
Pigments)
Traditional classification of pigments
Since the Middle Ages the pigments have been divided into two
classes: the natural and the artificial pigments. Later on, the
mineral (or anorganic) pigments were set against the organic
ones.
The anorganic or mineral pigments are principally metallic salts
or oxides like cadmium sulfide or iron oxide.
The organic ones are made up from carbon and hydrogen and often
oxygen and nitrogen too (sometimes with other elements in
addition). All the living beings are made up from organic
substances, and all the minerals, like the water, the earth or the
stones, are anorganic ones. (See Examples of
chemical formules.)
In consequence, one knows four categories of pigments:
- Natural anorganic pigments, like the natural earths
(e.g. Yellow Ochre), which mainly contain iron oxides, and some
precious stones (e.g. Lapis Lazuli or Genuine Ultramarine);
- Synthetic anorganic pigments, produced by the industry,
like ferric ferrocyanide (Prussian Blue), synthetic iron oxide
(Mars Pigments), cobalt aluminate (Cobalt Blue), etc.;
- Natural organic pigments, which come principally from
plants, like the Genuine Madders, extracted from the madder root,
or like Indian Yellow, which came from dried urine of Indian cows,
fed with mango leaves;
- Synthetic organic pigments, like copper phthalocyanine
(Phtalocyanine Blue PB15) or brominated anthranthrone (PR168).
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Permanence and Lightfastness
The former theoretical classification is not of great interest
for the painter. What he wants to know is “Will my colors
stand the test of time?” In other words, he wants to work
with permanent pigments, i.e. lightfast pigments that don´t
fade in the light and solid pigments that will not be discolored
when being in contact with other substances like other pigments,
binders, or the polluted air of the towns.
- Lightfastness: durability of a pigment when exposed to
light.
- Permanence: durability of a color, including
lightfastness AND stability of the pigment exposed to noxious
agents like the polluted atmosphere. This permanence depends not
only on the pigment, but on the medium too.
So a lightfast pigment can be permanent in oils and nonpermanent
in watercolors or fresco, or conversely. Lead White PW1 is
absolutely permanent in oils but becomes quickly black in
watercolors, because this medium doesn´t protect it against
an atmosphere polluted with sulfur compounds (sewers and automobile
exhausts in the towns, manure and fertilizers in the country).
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Lightfastness of the pigments of the 21th century
In the 19th and 20th centuries, the chemistry gave us an
enormous quantity of pigments; some of them being very bright.
Unfortunately, most of these bright colors had no lightfastness at
all.
That´s the reason why, about one year in two since 1987, I
personally tested the lightfastness of a lot of colors from the
best brands, which I exposed at the sunlight behind a window. So
I’ve seen that the manufacturers are sometimes too optimist
about the lightfastness of the pigments they sold to the artists.
Sometimes too — but not so often — they aren’t
enough! (See “Personal
Trials”)
(Back to History of
Pigments)
Here follows a classification of the main pigments that can be
found in modern trade, based on their permanence. In other words,
this list is not complete. The absence of a pigment does not mean
that it´s not a good one, but only that it is not so usefull
in the practice. Conversely, I have included pigments that are
seldom used, but which have some particular characteristic that may
make them indispensable in some circumstances.
My symbols for permanence (explanation in the text below):
| ¶¶+ |
Absolutely permanent pigments |
| ¶¶ |
Extremely permanent pigments |
| ¶+ |
Very permanent pigments |
| ¶ |
Permanent pigments |
| (¶) |
Probably permanent pigments |
| Ø |
Nearly permanent pigments |
| ØØ |
Nonpermanent pigments |
| ØØØ |
Fugitive pigments |
| ØØØØ |
Very Fugitive pigments |
| ØØØØØ |
Very Bad pigments |
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Absolutely permanent pigments
The most permanent of all pigments are whites, blacks, natural
earths and synthetic iron oxides. Some of them indeed have been
used for ten to fifteen thousand years without fading.*) **)
*) The colors of all the tables below are approximate.
It´s indeed impossible to guarantee an accurate
representation of colors on the screen, which depends on the
adjustment of every monitor.
**) These colors are best seen with Microsoft
Internet Explorer 6.0, Netscape 6.2, Opera 6.0 and NeoPlanet 5.2.
Some old browsers don´t show the colors of these tables
correctly; other ones don´t show them at all.
| ¶¶+ |
Yellow Ochre PY43 |
|
| ¶¶+ |
Raw Sienna PY43 |
|
| ¶¶+ |
Burnt Sienna PBr7 |
|
| ¶¶+ |
Raw Umber PBr7 |
|
| ¶¶+ |
Burnt Umber PBr7 |
|
| ¶¶+ |
Light or English Red (Red Ochre) PR101 or
PR102 |
|
| ¶¶+ |
Venetian Red PR101 or PR102 |
|
| ¶¶+ |
Indian Red PR101 or PR102 |
|
| ¶¶+ |
Lamp Black PBk6 |
|
| ¶¶+ |
Ivory Black PBk9 |
|
| ¶¶+ |
Mars Black PBk11 |
|
(Back to top)
Extremely permanent pigments
Here is a list of bright pigments that are extremely permanent,
but perhaps not so lightfast than the natural earths. They
won’t fade in the sun, but nobody can guarantee they will
continue to resist to direct sunlight during several centuries.
Nevertheless, in the light of a museum or in a house, they probably
will be lightfast for more than 500 years.
So we are authorized to say that these pigments are
probably absolutely permanent. But at the present time we are
in general incapable of being objective about it, the oldest among
them being less than 200 years old! With the passing of time our
grand-grand-grand children will judge better than us.
| ¶¶ |
Titanium White PW6 |
|
| ¶¶ |
Zinc White PW4 |
|
| ¶¶ |
Nickel Titanium Yellow PY53 |
|
| ¶¶ |
Cobalt Green PG19 |
|
| ¶¶ |
Viridian (hydrated oxide of chromium) PG18 |
|
| ¶¶ |
Opaque Oxide of Chromium PG17 |
|
| ¶¶ |
Cerulean Blue PB35 |
|
| ¶¶ |
Cobalt Blue PB28 |
|
| ¶¶ |
Cobalt Violet (Light) PV14 |
|
| ¶¶ |
Cobalt Violet Dark PV14 |
|
| ¶¶ |
Mineral (= Manganese) Violet PV16 |
|
You will immediatly remark that this range doesn’t contain
any bright orange or red. Even Nickel Titanium is a grayish yellow
with a greenish shade. The only bright blue of this palette, Cobalt
Blue, has a greenish shade too and not much coloring power.
Cerulean Blue is a grayish-whitish blue with a greenish shade.
Cobalt Violet has an extraordinary beautiful hue, near spectral
violet; but its coloring and covering power is so weak that this
pigment is rather difficult to handle. Manganese Violet is
excellent but not so bright as the Cobalt one.
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(Back to Prices)
Very permanent pigments
| ¶+ |
Flake White (= White Lead, Silver White, etc.)
PW1 |
|
| ¶+ |
Cadmium Lemon PY35 |
|
| ¶+ |
Cadmium Yellow Light (or Pale) PY35 |
|
| ¶+ |
Cadmium Yellow Medium PY35 |
|
| ¶+ |
Cadmium Yellow Deep PY35 |
|
| ¶+ |
Cadmium Orange PO20 |
|
| ¶+ |
Cadmium Red Medium PR108 |
|
| ¶+ |
Anthranthrone Red PR168 |
|
| ¶+ |
Cadmium Red Deep PR108 |
|
| ¶+ |
Ultramarine Violet PV15 |
|
| ¶+ |
French Ultramarine PB29 |
|
| ¶+ |
Phthalocyanine Blue PB15 |
|
| ¶+ |
Indanthrene Blue PB60 |
|
| ¶+ |
Phthalocyanine Green PG7 |
|
These pigments are very permanent, and perhaps they would
deserve the qualification ¶¶ (extremely permanent),
But:
- either they are too young yet (less than one century: phthalo
blue and phthalo green were discovered in 1935),
- or they have a chemical problem: they need to be mixed with
some other ones with caution, otherwise there will be a chemical
reaction between them and other pigments, or between them and other
chemicals contained in the mediums or in the polluted air. For
example, the Cadmiums are lead sensitive and Flake White is sulfur
sensitive. Never mix Flake White with Cadmium pigments, the lead of
the white may combine with the sulfur of the cadmiums to produce
lead sulfide, which, being black, will discolor the mixture.
Like the natural mineral Lapis Lazuli, French Ultramarine
(chemically synthetized Ultramarine), is extremely sensitive to
acids, which bleach it.
We have bright yellows and reds at last. French Ultramarine is
the bluest of all the known blue pigments. Phthalocyanine Blue has
a strong green shade. Phthalocyanine green is near Viridian, but
brighter.
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Permanent pigments
Until the nineties, when the artist needed a bright transparent
yellow, there was only one: Cobalt Yellow PY40 (Aureolin). But this
beautiful color was not really permanent. Now we have a marvelous
transparent yellow: Chromophytal Yellow PY 128, which I
haven’t been able to make fade in direct sunlight — even
strongly diluted in a medium for glazes.
| ¶ |
Chromophytal (Transparent) Yellow PY128 |
|
| ¶ |
Permanent Rose (Quinacridone) PV19 |
|
| ¶ |
Permanent Magenta (Quinacridone) PV19 |
|
These quinacridones PV19 probably deserve to be placed among the
¶+ pigments. According to my trials, maybe PY128 too.
Let’s wait the test of the time.
Note:
There are numerous quinacridone shades, and my
personal trials have showed that the lightfastness of some most
orange shades of PR207 are not so good as the one of these
PV19.
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Probably permanent pigments
Until recently, there was a problem with nonpermanent alizarin
(and the natural madders too), which could not be replaced easily
by any quinacridone, because no quinacridone has exactly the same
hue than Crimson Alizarin. You had to mix Quinacridone Rose with
darker pigments like French Ultramarine, brown earths and black.
But this operation wasn’t very easy and the results were not
always satisfactory.
At the very end of the 20th century, two pigments were
introduced as substitutes for these nonpermanent, but useful
pigments. The future will say if they deserve to be placed higher.
According to the present state of my personal trials (I have tested
them only one time), I can say that their lightfastness is much
better than the one of alizarin, the ordinary madders and some
other pigments. (So far, I haven´t been able to make them
fade when exposed to sunlight.) But I do not know yet if they are
as permanent as e.g. the quinacridones. That´s why I give
them “(¶)”, i.e. a provisional permanence rating. I
add to this list a absolutely transparent bright red: Transparent
Quinacridone Red PR207 (tested only one time
too).
| (¶) |
Permanent Madder Deep PR264 |
|
| (¶) or Ø |
Permanent Crimson Alizarin
PR177 1 |
|
| (¶) |
Transparent Quinacridone Red PR207 |
|
- In 2001, I considered this pigment to be “probably permanent”. In September 2002, my last trial seemed to be about to show a relative frailty of this PR177 to the light, what would have given this pigment the permanence rating “Ø” (= nearly permanent pigment) rather than “(¶)” (= probably permanent pigment). I had hoped to be able to precise this diagnosis with more accuracy before the end of the year but unfortunately, owing to the poor weather of the last months, I couldn’t. So I’ll continue this trial next spring untill I am absolutely sure of the exact permanence rating of this PR177. (See Trials — The New “Permanent” Alizarines.) — note added in September 2002 and updated January 20th 2003.
So far, all the pigments I have talked about are listed as
Excellent (I) by the ASTM (American Society of Testing and
Materials). You can see that, in my opinion, there are five classes
of “excellent ASTM I” pigments, some of them being
“much more excellent” than others!
Some pigments are listed as ASTM II (Very Good) or ASTM III
(Fugitive). I hardly ever use these pigments any longer, since
there exist enough good permanent pigments now.
In the past, when I needed a particular shade, I used to paint a
glaze of a transparent bright pigment on an underpaint of a less
bright pigment of nearly the same shade. So doing, if the bright
superficial pigment would fade, the color wouldn´t be
modified: only its shade would be less bright. An example: a glaze
of Aureolin PY40 (ASTM II) on an underpainting made with
Cadmium Yellow PY35. But now we don´t need Aureolin any more:
we have the Transparent Chromophytal Yellow PY128, which is
permanent (¶ & ASTM I).
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Not really permanent and more or less fugitive pigments
Sometimes you´ll be captivated by some brilliant shade,
but remain cautious! Many of them are not really permanent, often
even fugitive. Nevertheless, I think it will be useful for you to
know some of them.
This needs more explanation about “nearly
permanent”, “nonpermanent”, “fugitive”
and “bad” pigments:
- Ø: Nearly permanent pigments: those which have
resisted to all my lightfastness trials but one;
- ØØ: Nonpermanent pigments: those which
haven´t resisted to my lightfastness trials, but which had
some or other reason for being considered as (nearly) permanent
until more or less recently;
- ØØØ and
ØØØØ: More or less fugitive
pigments: those which haven´t resisted to my
lightfastness trials, the number of “Ø” depending
on the relative fugitiveness that was observed in my tests;
- ØØØØØ: Bad pigments:
pigments worse than alizarine PR83.
| ØØ |
Arylide Yellow 10G (Arylamid Yellow) PY3 |
|
| (¶) |
Arylide yellow GX PY73 |
|
| ØØ |
Cobalt Yellow (Aureolin) PY40 |
|
| (¶) |
Arylide yellow 5GX PY74 |
|
| (¶) |
Pyrrole Red PR254 |
|
| Ø |
Naphthol Red (Naphtol AS OL) PR9 |
|
| Ø |
Naphthol Red (Naphthol AS-TR) PR7 |
|
- As I´ve just said, (transparent) Cobalt Yellow
PY40 is easily replaced by Chromophytal Yellow PY128.
- The Arylide Yellows (PY3, PY73 and PY74) can sometimes
replace the Cadmiums, but at your own risks concerning
permanence.
- Pyrrole Red PR254, and both Naphthol Reds PR7 and
PR9 are unnecessary shades.
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Pigments to avoid like the plague
I’m always astonished to see many painters and books on
painting still recommanding unsafe pigments which I consider you
have to avoid like the plague. Here are the most striking
examples.
| ØØØØØ |
Chrome Yellow Light PY34 |
|
| ØØØØØ |
Chrome Yellow Medium PY34 |
|
| ØØØØØ |
Chrome Yellow Deep PY34 |
|
| ØØØØØ |
Chrome Orange PR34 |
|
| ØØ |
Vermilion PR106 |
|
| ØØØØ |
Crimson Alizarin PR83 |
|
| ØØØ |
Dioxazine Purple (or Violet) PV23 |
|
| ØØ |
Prussian Blue PB27 |
|
- The Chrome Yellows PY34 and Chrome Orange PR34
receive the permanence rating
ØØØØØ. To be honest, I must say
I never have tested them personally, but in the past nearly every
manufacturer used to classify them at a worse level than alizarine
PY83, because they are lead compounds that can easily discolor in
an atmosphere containing sulfurated hydrogen (e.g. air polluted
with sewer emanations). It is also well known that Van Gogh’s
Sunflowers, painted with Chrome Yellow, have turned green with the
time (yellow plus black make green). Furthermore, the Chrome
pigments are very easily replaced by the Cadmiums, with the same
hues.
- Vermilion PR106 becomes more and more difficult to find
in the trade. It’s not a great loss. It´s a very
expensive pigment, which turns black after a period of exposure to
light. But (according to the best authors) this process is rather
capricious: there are masterpieces of the 15th century where
Vermilion isn´t discolored at all, and other ones in which
the pigment has turned black. A personal trial (made in 1988) has
undoubtly confirmed this blackening. Nowadays, Vermilion is very
easily replaced by Anthranthrone Red and the Cadmiums.
- Dioxazine Purple (= Dioxazine Violet — sometimes
called Carbazole Violet, because its chemical formule is Carbazole
Dioxazine) PV23 is still recommanded by most color manufacturers,
and yet it doesn’t deserve to be maintained in the list of
permanent pigments (my personal tests have established without any
doubt that it fades in the sunlight), what is confirmed by its ASTM
rating II. Strangely enough, Mineral Violet (= Manganese
Violet) PV16, which is a perfectly permanent substitute for it,
doesn’t even appear in many books and manuals on oil
painting.
- Prussian Blue (PB27) is an unstable pigment that fades
in the light and becomes again normal in the dark. It is said to be
fugitive if strongly diluted with zinc or titanium white. It’s
easily replaced by Phthalocyanine Blue PB15, and even by
Indanthrene Blue PB60.
The color lists of most renowned color manufacturers for artists
are crammed with fabulous colors names like Payne’s Gray,
Hooker’s Green, Sap Green, Chrome Green, Cadmium Green, Olive
Green, Naples Yellow, Royal Blue, Flesh Tint, etc. All these colors
are unnecessary, because they are mixtures of several pure
pigments; in addition, their composition and their lightfastness
vary from one brand to the next.
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The safest way
I recommand that you always make yourself your mixed colors
starting from pure ones. For example, Payne’s Gray is very
easily made extemporaneously by mixing Black and Ultramarine on
your palette. You can reproduce every fantastic green by mixing
Viridian (or Phthalo Green) with yellows, orange or earth pigments.
Even Phthalo Blue can produce very beautiful greens. So, make your
own trials!
Nevertheless, there are a few exception to this
golden rule. When a pure natural pigment like Burnt Umber is
replaced by a safer mixture of absolutely permanent pigments like
PR101 and e.g. PBk11, I recommand the newer composite pigment
without any reservation. Another exception is Light (English) Red,
which can (rarely) be a mixture of PR101 and PY42 (See “The Problem of the
Browns”.)
An example: for getting a perfectly permanent Sap Green, try to
mix Viridian PG18 with Transparent Yellow Oxide PY42. You can see
it on the image below. (It works with Phthalo Green PG7 too, but
the result will be less permanent.)
Click on the image for getting it bigger
| Page updated January 20th 2003 |
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