The Edit — Craft
Lightfastness: Whether a Painting Survives
Two tubes of the same colour can be the same price and behave completely differently over ten years on a wall. The difference is printed on the tube, in a code most people never learn to read.
This guide is research-led: we have not handled these units ourselves. If you buy through our links we may earn a commission — it never changes a pick. How we choose
Lightfastness is how well a pigment resists fading under light. It is measured, it is published, and it is the specification that decides whether a painting looks the same in 20 years or has quietly lost its reds.
Two scales, and both appear on tubes
ASTM D4303 is the American standard, and it runs in categories rather than numbers.
| ASTM rating | Meaning |
|---|---|
| Category I | Excellent. Permanent |
| Category II | Permanent for all normal display |
| Category III | Fair. Fades in normal display conditions |
| Category IV and V | Fugitive. Fades in months to a few years |
The Blue Wool Scale is the European equivalent, running 1 to 8, where 8 is the most permanent. Manufacturers frequently print their own star ratings alongside, and those are marketing rather than standards.
Anything at Category I or II, or Blue Wool 7 to 8, will outlive you in ordinary indoor light. Category III and below will not.
The pigment code is the real name
Every pigment has a Colour Index generic name: a letter pair for the family and a number for the specific pigment. PB29 is ultramarine. PR108 is cadmium red. PY35 is cadmium yellow. PV19 is quinacridone.
That code is the only reliable identifier on a tube. Colour names are marketing and vary between brands — one maker’s Crimson is another’s Rose — while PR83 is PR83 everywhere in the world.
A tube listing a single pigment code mixes cleanly. A tube listing 3 codes is a convenience mixture, and mixing it with another mixture is how paintings turn muddy.
What the word “Hue” means
“Hue” after a colour name means the tube does not contain that pigment. It contains a mixture formulated to look like it, usually because the real pigment is expensive, toxic, or both.
Cadmium Yellow Hue is not cadmium. Cobalt Blue Hue is not cobalt. This is disclosed rather than hidden — the word is right there on the tube — but almost nobody is told what it means.
Substitutes are not automatically worse for permanence. They are reliably different in mixing behaviour, granulation and opacity, and a painting planned around real cobalt will not reproduce with the substitute.
Winsor & Newton Cotman Watercolour, 21ml Tube, Cobalt Blue Hue
12,862 ratings on a tube whose name ends in Hue, which means it is a mixture imitating cobalt rather than cobalt — and the listing says so plainly.
Current price shown on Amazon. We may earn a commission.
| Range | Cotman, the student line |
|---|---|
| Name | Hue — a substitute mixture |
| Owners praise | Colour per stroke, price |
12,862 ratings makes this the most-evidenced watercolour tube on the shelf, and the last word of its name is the one this page is about. Cobalt Blue Hue is a mixture imitating cobalt, and Winsor & Newton say so on the label rather than burying it.
Owners praise the colour delivered per stroke and the quality for the price, and both are fair. Cotman is the student range: less pigment, more filler, more substitutes. For learning and for volume that is exactly right, and it is the wrong tube for something going on a wall for 20 years.
Buy it if
- You are learning and using a lot of paint
- The work is practice rather than permanent
Don't buy it if
- The painting is going on a wall for a decade
Student grade and artist grade differ in three ways
Pigment load. Artist grade carries more pigment per volume, so 1 pass reaches full strength where a student paint needs 2 or 3.
Single pigments. Artist ranges use one pigment per tube far more often, which is what keeps mixes clean.
Substitution. Student ranges lean on hues, because cadmium and cobalt are the expensive part of the tube.
Lightfastness is not automatically one of the three. A well-made student paint can rate Category II, and the difference shows in handling long before it shows in fading.
Winsor & Newton Cotman Watercolour Paint Set, 12 Colours, 8ml
The student range in a 12-tube set, and owners describing exactly what a student grade is for — mixing, learning, and using without counting the cost.
Current price shown on Amazon. We may earn a commission.
| Range | Cotman, the student line |
|---|---|
| Tubes | 12 x 8ml |
| Watch | Durability opinions mixed |
The highest-rated set here, and the reports describe a student range accurately: rich colours that mix into a wide range, easy to use, and a texture that goes milky in a wash — which is filler doing what filler does.
Owners call it suitable for beginners and students, which is what the range is named for. Buy it to learn on, and read the pigment codes on individual tubes before assuming any given colour is a single pigment.
Buy it if
- You are building a first palette
- You mix your own secondaries
Don't buy it if
- You want single-pigment paints for clean mixes
The pigments that actually fade
Alizarin Crimson, in its original PR83 form, is the classic example — beautiful, widely sold, and rated poorly for permanence. Most manufacturers now offer a Permanent Alizarin as a substitute for exactly that reason.
The other groups to check are the fluorescents, which are fugitive by construction, and some of the cheaper violets and pinks. Earth pigments at the other end — the ochres, siennas and umbers — are among the most permanent things you can put on paper.
Where a set publishes no lightfastness data at all, assume nothing. That is not evidence of a bad paint; it is an absence of evidence, and it is common at the volume end.
Paul Rubens Artist Grade Watercolour Set, 24 Colours
Sold as artist grade, and owners report the property that actually distinguishes one — pigment load heavy enough that mixes stay clean instead of going muddy.
Current price shown on Amazon. We may earn a commission.
| Grade | Artist, per the listing |
|---|---|
| Owners praise | Pigmented, blends without muddying |
| Watch | Reports of debris in pans |
Owners report the property that genuinely marks an artist grade: heavy pigmentation, a creamy rather than chalky consistency, and mixes that blend without going muddy. Muddiness is usually a mixture-on-mixture problem, so paint that avoids it is paint doing something right.
What the listing does not publish is per-colour lightfastness, which is the specification this page argues for. Treat the grade claim as a description of handling, and check individual pigment codes before committing a colour to a finished piece.
Buy it if
- You want density without a European price
- You mix rather than use colours straight
Don't buy it if
- You want published lightfastness per colour
MEEDEN Professional Artist Watercolour, Payne's Grey, 15ml
A single professional-line tube, which is how a palette should be built — one pigment at a time, chosen for what it does.
Current price shown on Amazon. We may earn a commission.
| Format | Single 15ml tube |
|---|---|
| Owners praise | Steady pigmentation |
| Note | Payne's Grey is a mixture by definition |
A single tube is how a working palette is actually built — colours run out at different rates, and replacing them one at a time beats buying another set. Owners describe steady pigmentation and good value.
Worth knowing about this particular colour: Payne’s Grey is a mixture by definition rather than a pigment, usually blue plus black plus sometimes a red. That is not a criticism, but it does mean its behaviour varies by maker more than a single-pigment colour would.
Buy it if
- You replace colours individually as they run out
- You want to test a line before committing
Don't buy it if
- You want a complete set in one purchase
What to check before buying
Look for the pigment code, the ASTM or Blue Wool rating, and the absence of the word Hue if you want the named pigment. A maker that publishes all 3 for every colour is telling you it has tested them.
Then match the paint to the job. Practice work does not need permanence, and the paper matters as much as the pigment for anything that does — which is why gsm decides everything, and the same read-the-specification habit as the yarn weight system.
The quick list
Every pick, in order. Jump to the full test on any of them.
- Most-reviewed, and the word to notice is Hue
Winsor & Newton Cotman Watercolour, 21ml Tube, Cobalt Blue Hue
12,862 ratings on a tube whose name ends in Hue, which means it is a mixture imitating cobalt rather than cobalt — and the listing says so plainly.
4.8from 12,862 verified reviews - Highest rated
Winsor & Newton Cotman Watercolour Paint Set, 12 Colours, 8ml
The student range in a 12-tube set, and owners describing exactly what a student grade is for — mixing, learning, and using without counting the cost.
4.8from 1,889 verified reviews Paul Rubens Artist Grade Watercolour Set, 24 Colours
Sold as artist grade, and owners report the property that actually distinguishes one — pigment load heavy enough that mixes stay clean instead of going muddy.
4.6from 1,377 verified reviewsMEEDEN Professional Artist Watercolour, Payne's Grey, 15ml
A single professional-line tube, which is how a palette should be built — one pigment at a time, chosen for what it does.
4.6from 136 verified reviews