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What Is Lightfastness And Why Does It Matter?

Have you ever noticed your coloured pencil artwork fading over time?

Understanding lightfastness can preserve your creations and save hours of effort from fading into obscurity under bright sunlight.

Lightfastness measures how well pigments resist fading when exposed to light, particularly harmful ultraviolet (UV) rays. For artists, this knowledge is key to ensuring their work retains its vibrancy and beauty for years.

Before examining lightfastness in colored pencils, here's how light affects different art materials:

  • Watercolours: With their delicate, thin layers, watercolours are especially vulnerable to fading. Completed pieces are often stored away from bright light or displayed cautiously under UV-protective glass to preserve their colours.
  • Oil Paintings: The thick layers and protective oil binders provide some resilience. However, many "Old Masters" paintings have lost their original vibrancy over centuries due to dirt, varnish degradation, and light exposure.
  • Acrylics: Modern acrylic paints benefit from durable polymer binders and advanced pigments, making them more resistant to fading than many traditional media.
  • Inks: Often derived from stable pigments, inks tend to be among the most lightfast water-based mediums.

Understanding these differences provides a valuable foundation for grasping how coloured pencils perform under similar conditions.

Lightfastness in Coloured Pencils

Coloured pencil art is as sensitive to light as other media and requires similar protective measures.

Certain pigments are more prone to fading—reds, purples, pinks, and some blues are often less stable than natural browns, yellows, and greens.

Thankfully, advancements in modern chemistry and synthetic pigments have led to fade-resistant formulations, especially in professional-grade coloured pencils.

Why Older Pencils May Fade More Quickly

Older pencils often contain less stable pigments.

Modern manufacturers, aware of the demand for durable colours, have improved their formulas.

However, not all pencils are created equal.

  • Student and Budget Lines often use cheaper pigments that fade faster.
  • Professional Artist Lines feature highter-quality pigments with better lightfastness ratings but come at a premium price.

The images above demonstrate colour fading from non-lightfast pencils. The first photo shows the drawing at completion, the second after 6 months of exposure to Mediterranean sunlight.

Why Do Watercolour And Wax Pencils Carry Different Ratings?

Lightfastness ratings differ between watercolour (aquarelle) and wax-based (non-soluble) pencils, even when the same pigments are used. This variation is due to the thickness of the pigment layer.

Wax-Based Pencils: Produce thicker, more resilient pigment layers resulting in higher lightfastness.

Watercolour Pencils: Create thinner layers when diluted with water, making them more prone to fading.

Caran d'Ache's Museum Aquarelles, launged in 2013, demonstrate that excellent lightfastness is achievable in watercolour pencils. Most score 3+ stars on the Blue Wool Scale, whether used wet or dry.

How Is Lightfastness Measured?

Lightfastness ratings measure a pencil's resistance to fading. Common rating systems include:

Blue Wool Scale: 1-8, with 8 being most lightfast. Ratings of 6+ are suitable for professional work.

Star Ratings: 1-3 stars, where 3 stars indicates high durability.

ASTM Ratings:

  • ASTM D6901: Tests lightfastness on coloured pencils directly, providing highly reliable results. LF1 (excellent) and LF2 (very good) are the highest ratings.
  • ASTM D4303: Evaluates the pigments used in pencils and other art materials. While less specific to the pencil itself, it offers a good indication of colour longevity.

Avoid using pencils rated below Blue Wool 5 or with single-star ratings for work you want to last.

Manufacturers Lightfastness Settings

To ensure durability, always check manufacturers' ratings or documentation. For example:

FABER CASTELL (use their own star system) - try to avoid 1 star pencils

CARAN D'ACHE (also use a star system for brands other than Luminance and Museum) - Avoid 1 and 2 star pencils

Luminance ratings are given as LF1 and LF2 - according to the ASTMS 6901 data, LF1 is 100% lightfast and LF2 is 80% lightfast. All Luminance colours can be considered fine for coloured pencil work. 

DERWENT (use the Blue Wool Scale) - try to avoid 1 and 2 star pencils

Derwent Lightfast - All the colours comply with ASTMS 6901.  The pencils are OIL based (a new departure for Derwent  who usually base their ranges on wax or mainly wax and some oil).  Softer than Faber Castell Polychromos.  An expensive pencil, on a par with Luminance for cost.

PRISMACOLOR - Sanford have been very coy in the past about publishing the data.

However  they have now published an official Prismacolor Premier Chart showing the colour card and the official ASTMS 6901 ratings for their 150 colours.

They show the range with the 5 grades listed from excellent ( 1 ) to poor ( 5 )

On this scale, the serious coloured pencil artist would normally be aiming to use those in grades 1 and 2 and there are 72 colours Prismacolor Premier pencils that match this aim, with quite a few of the ‘good’ colours, shades of grey or white.

OTHER BRANDS

Staedtler and Lyra do not publish data on the internet - or if they do, I haven’t found it in any leaflets. UV star ratings for Lyra are shown against each colour inside the lid of the box.

TALENS (VAN GOGH) - Talens say that the Van Gogh range ‘meet the standards of ASTMS 6901’

I also understand the Dutch made Bruynzeel FullColor pencils are lightfast, but I have no data to back this up.

CRETACOLOUR - Made in Austria by the successors to the Hardmuth pencil business.

Colours of the 36 Karmina (dry point) and Marino (watercolour) pencils meet the ASTMS 4303 standard with all colours either LF1 or LF2.

Karmina can be very difficult to find, but Marino are on sale in the UK and I have tested them as very good (and not highly priced).

Tips for Protecting Your Coloured Pencil Artwork

Even with high-quality, lightfast pencils, additional measures may help preserve your artwork:

  • Use UV-Blocking Sprays: Apply a fixative with UV protection to shield your work from harmful rays.
  • Frame with UV-Protective Glass: Mount your artwork behind glass or acrylic with UV-blocking properties for added defense.
  • Avoid Direct Sunlight: Store or display pieces in low-light areas to reduce exposure.

Although there is no direct evidence that these help, they are worth keeping in mind. 

Summing Up

Investing in lightfast coloured pencils and understanding how to protect your artwork is crucial for creating pieces that endure.

By using high-quality materials, checking lightfastness ratings, and applying UV protection, you can ensure your coloured pencil creations maintain their beauty for years to come.

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