Monday, February 04, 2008

How lightfast are your artist grade coloured pencils?

The coloured pencils which did NOT make the grade
My pencils which are NOT INCLUDED as 'lightfast' in the CPSA Lightfastness Workbook

Lightfastness is a major issue for coloured pencils - as indeed it is for all artists' materials and colours.

I tested my coloured pencils recently against the ratings for lightfastness in the CPSA Lightfastness Workbook Version 4 - and got a very big surprise. You can see it above - these are all my coloured pencils which did NOT make the cut because they are NOT listed in the CPSA Lightfastness Workbook as having an acceptable level of lightfastness. These are the ones which were in use and the picture excludes those that were in reserve and those which I've left in their boxes. Overall, we're talking a LOT of pencils - and a lot of money which has been spent on them.

What is lightfastness and why is it important?Lightfastness relates to the chemical properties of organic and inorganic pigments used to create artists' paints and colours. In essence it's about how fast colours lose their colour integrity. 'Fugitive' materials are those that will either bleach white or radically change colour in less than 20 years when displayed in a normal home environment. Archival standards require colours to last for a very long time.

Lightfastness is certainly not an issue which is unique to coloured pencils. All art materials are derived from the same basic sources and so it also applies to all other media used to produce artists' materials. The difference between pigment, paint and colour is not always well understood.
Because most artists have been trained under the "color theory" dogma that paints are just "colors", even knowledgeable artists or not always keep the distinction clear between pigments (colored powders), paints (mixtures of pigments and liquid vehicle) and "colors" (the product names given to paints). This results in frequent inaccuracies and outdated information in art instruction books.
Handprint - pigments, paints and colours
Not all pigments behave in the same way and have to be treated differently when making up colours. Concerns for artists arise when colours use pigments which are not lightfast or which have reduced lightfastness as they are weakened in strength - as in a watercolour wash or a pale tint of a colour.

Why is lightfastness in coloured pencils important?

Historically coloured pencils have mainly been used by illustrators and consequently work was not being produced with a view to longevity and lightfastness in coloured pencils was not a major issue.

As illustrators have increasingly switched to the use of digital technology the market for coloured pencils has changed. I don't know the figures but my guess would be that professional, semi-professional and amateur artists now make up a much larger proportion of coloured pencil buyers.
Naturally, artists want to work with materials which will not deteriorate with age and coloured pencil manufacturers are beginning to understand that this is becoming a major issue in relation to product development.
What's the lighfastness standard?
ASTM International (originally the American Society for Testing Materials) has a committee - ASTM D01.57. - which has developed and published eleven standards covering such topics as testing of pigments for lightfastness, labeling content, paint performance criteria, and the health hazard labeling of art materials. Three additional standards are currently in development.

It has a published statement about lightfastness which is applicable to all artists' materials. ASTM D4303-06 Standard Test Methods for Lightfastness of Colorants Used in Artists' Materials is highly technical.
ASTM D 4303 Standard Test Methods for Lightfastness of Pigments Used in Artists' Paints
This is a highly technical method that describes the ways in which pigments used in artists' paints (any kind of artists' paint) can be tested for relative lightfastness. It requires the use of color measuring instruments and instrumentally monitored exposure equipment. It details the preparation of test specimens and controls, describes the four types of simulated daylight exposures used in the method, and details how the test results are to be evaluated in order to place products on one of five lightfastness Categories.
The ASTM apply this standard when testing the lightfastness of all different types of artists materials and it forms part of the composite standard for each type of material. For example these are the latest standard specifications for:
(Note: There is no standard as yet for pastels although I understand ASTM are working on one.)

A further standard has also been published for use as a method which is simple and can be performed without instrumentation in a comparatively short length of time. I believe this is the one used by CPSA for its lightfastness workbook results.

ASTM D 5383 Standard Practice for the Visual Determination of the Lightfastness of Art Materials by Art Technologists
This practice describes a method for testing the relative lightfastness of art materials not covered by D 4302, D 5067, D 5098, and D 5724: non-traditional materials like colored markers, pastels, inks, colored pencils, and so on. The practice uses Blue Wool textile fading cards as controls to determine when the proper amount of natural daylight exposure has been reached. D 5383 does not require the sophisticated instrumentation of D 4302 to evaluate the results, but it is a less strenuous and less definitive test than D 4302. It does, however, reveal products that will fade or otherwise change if used, and enables the user to communicate the test results to others with a good degree of confidence.

How has lightfastness of coloured pencils been determined?

The Coloured Pencil Society of America are to be very much applauded for recognising early on that lightfastness would be an important issue for getting artwork in coloured pencil accepted by the art world and galleries generally. Accordingly around 1993 CPSA began to work with the ASTM on this issue with a view to developing a quality standard for coloured pencils.

In 2003, ASTM D6901-06 Standard Specification for Artists' Colored Pencils - which covered lightfastness ratings and labelling - was agreed and published. However, it was recognised that it would take a bit of time to implement.
Because ASTM D6901 is so recent, no colored pencil manufacturer has yet had time to officially comply with it, although the two companies mentioned prior have manufactured and tested pencils which will be able to comply when officially tested. When companies do comply, colored pencils will be marked with Lightfastness I and II symbols, allowing artists to choose lightfast colors.
CPSA Press Release 2003
In November 2003, CPSA identified the benefits of the new standard as follows
Major advantages of this new colored pencil lightfastness standard are:
  • Artists choosing lightfast colored pencils as their medium can now work with confidence in knowing that their art will not fade. Public awareness of this fact will increase their artworks value and profitability.
  • Collectors are becoming increasingly aware of the archival aspects of their artworks. Their interest is in the art’s lightfastness of medium, and the archival quality of the surface. Colored pencil art now ranks high in longevity of the medium, which is the ultimate asset for the collector.
  • Museum Conservators search for methods to make artwork last through the ages. As colored pencil is a viable fine art medium, it is imperative that ASTM D6901 addressed the issue of lightfastness. Brilliant works created by contemporary masters using colored pencil will be safely preserved because materials used were in compliance with the standard. This option is far better than salvaging a faded piece of work.
  • Prices for colored pencil art by renowned artists will command the same as for other mediums because of the advent of this lightfastness standard.
  • Retailer advantage lies in their ability to stock and sell quality higher-priced colored pencils that comply with ASTM D6901 to artists wanting their finished art to last.
Since the early 80s, work has been done in various places to determine lightfastness of coloured pencils on a formal and informal basis. Indeed it's perfectly possible for you to conduct tests and I've included a lot of links to information about lightfastness in my information site Coloured Pencils - Resources for Artists in three sections.
So far as I am aware, there have been two major pieces of work done around testing for lightfastness.
  • The original work done to produce the first standard for coloured pencils. This involved the following manufacturers - Sanford (Prismacolor), Talens (Van Gogh) and Derwent
  • the testing done by Rhonda Farfan on behalf of CPSA and reproduced in the CPSA lightfastness workbook which I believe followed the art technologist standard.
So far the only manufacturer labelling pencils according to the CP standard is Sanford - and this only relates to its new Premier Lightfast range. Their site also provides details (pdf file) of the conduct of the testing done to determine the lightfastness results for pencils in this range.

How can I get hold of the lightfastness workbook?

The CPSA Lightfastness Workbook is only available to members of the Coloured Pencil Society of America. I joined as an International Member for two reasons (1) to go to the convention in the USA in 2006 and (2) to get my hands on the lightfastness workbook. Having said that I kept forgetting to order it!

When I finally placed my order, the website indicated that a new version is due out Spring 2005 and all orders would be held for that. Which was fine with me as Version 5 and the new test results for 2005-2007 contains the results for the following brands. Since Derwent Coloursoft is aimed at the Karisma (UK version of Prismacolor - now discontinued) market I was happy to wait.
  • Prismacolor Premier Lightfast
  • new Prismacolors
  • Caran d'Ache Neocolors
  • Derwent Coloursoft
  • Derwent Graphitint
  • Derwent Inktense
  • Fantasia Premium Artist Colour
  • Koh-I-Noor Progresso Woodless
  • Daler-Rowney Artists' Watercolor
  • Blick Studio Artists' Colored
And then Version 4 turned up in the post as there had been a mix-up! This includes testing of the following brands of coloured pencils (in alphabetical order):
  • AW Faber Castell Polychromos
  • Bruynzeel Design Fullcolour
  • Caran d'Ache Pablo
  • Derwent Artist series
  • Derwent Signature
  • Lyra Rembrandt Polycolor
  • Royal Talens Van Gogh
  • Sanford Prismacolor
  • Sanford Prismacolor Premier Lightfast (I'm assuming this relates to the initial batch of colours)
  • Stabilo Softcolor (discontinued)
  • Sanford Verithins
  • Metallics (all brands)
  • Water-soluble Pencils
    • Caran d'Ache Supracolor Aquarelle
    • Bruynzeel Aquarell
    • General Kimberley's Thin Lead Watercolor
    • Sanford Prismacolor Watercolor
    • AW Faber-Castell Design Watercolour
    • Derwent Art Sticks
    • Derwent watercolour
    • Derwent Metallic pencils
    • Derwent Signature Watercolour
    • Lyra Rembrandt Aquarell
    • Royal Talens Van Gogh Aquarelle
    • Cretacolor Aquamonoliths
So there I was with a stack of pencils and a brand new unused workbook which wasn't the one I'd ordered.....

Reader - I could not resist! After checking I'd still be getting Version 5 as well, one weekend before Christmas I sat down and worked my way through my entire collection and completed the CPSA Lightfastness workbook.

I was absolutely staggered - gobsmacked even! - at just how many pencils across various brands failed to make it into the book. My pinks, reds, crimsons, purples, violets, blues, lime greens and pale coloured greys were completely decimated. The image you see at the top are all the "rejects". On the other hand these are exactly the same colours which have problems in other media.

By the time I got to the end only one make/brand had a really good track record for the percentage of pencils accepted as lightfast and 'approved' and included in the book. Now as it happens I own a virtually complete set of that brand so it came as something of a relief. Anybody want to take a guess which one it was?

I'm making it a rule from now on that all my original artwork must use lightfast pencils. I refuse to throw my 'reject' pencils away. What I'm going to do is keep them entirely separate and only use them for work which will be produced as prints - the original will never be sold. In terms of existing artwork, I'm going to withhold it from sale only if I know I used a lot of particular colours with particularly weak ratings and/or protect it in other ways.

The other great thing about the CPSA workbook though is that I can now photocopy the pages to take out with me and use as a checklist for when I'm doing any buying. The workbook format means that I can also easily see where I am missing colours which are considered lightfast according to the blue wool tests. However a list of names as a pdf file on the CPSA website would be very helpful as well.

The way forward
The ASTM D6901 Standard actually requires that manufacturers put the Colour Index Name on pencils in order for them to claim compliance with the Lightfastness Standard. We fought very hard to have that requirement in the Standard, and we need to make sure the manufacturers know that it is important to all of us.
Betsy Holster, Director of Product Research
Kay Schmidt, President
Vera Curnow, Founder
Rhonda Farfan, Vice President of Consumer Standards Emeritus
I have two major quibbles about the current state of affairs.
  • Not all manufacturers produce clear statements of compliance with the standard and ratings of pencils - this means artists are not well informed about the particular lightfastness ratings of different colours in different brands of coloured pencils
  • lightfastness test results and the CPSA workbook are only available to CPSA members. Given the lack of progress with testing and labelling by manufacturers, knowledge about lightfastness issues cannot be reserved for CPSA members only - even if the book is sold by the CPSA. It's my belief that products only become responsive to buyer requirements when buyer behaviour changes - and for that buyers need better information to effect that change.
A delicate balance must be struck in relationships between art societies and the manufacturers of art materials. The latter can be patrons but they can also be slow to make improvements to quality if changes in production are required and can sometimes be an obstacle to progress around the quality of art materials being used from the artists' perspective.

It makes me wonder whether a case can be made for having an International Forum for Coloured Pencil artists on which universal matters of importance could be discussed and progressed. After all, lightfastness is a matter of international significance and the benefits identified by CPSA when the lightfastness standard for coloured pencils was produced cannot be achieved unless all CP artists - including non-CPSA members - have better information.

My Recommendations

How can we all help to change the current state of affairs? Well if you are a member of CPSA then I definitely recommend that you order the lightfastness results and also get hold of a copy of Version 5 of the Lightfastness Workbook when it is published

Here are a few other suggestions which I'm currently working on....
  1. Lobby ALL the CP manufacturers for better and more accessible information about lightfastness. Five years on from the publication of the standard I expect to see more progress.
    • all pencils now need proper labelling. If they are not properly labelled one has to question whether they can be referred to as artist standard.
    • In the interim, I'd like to see colour charts published on websites that have each colour with a rating validated using ASTM D4303 (which is the standard which applies to manufacturers) and a clear statement as to the pigments used. This is already available for other artists' materials - why not artist grade coloured pencils?
  2. Lobby your own coloured pencil art society for better and more accessible information for artists.
  3. Ask CPSA (see contacts) to licence the CPSA workbook for sale to members of other national coloured pencil societies. This avoids all coloured pencil societies having to reinvent the wheel! A licence would also enable CPSA to recoup a fair income.
  4. Lobby for CPSA to place the workbook on sale for non-CPSA members. The information is too important to restrict it to members only. Wider usage would start to change buying behaviour. Pricing for different types of buyers (eg members and non-members of CPSA) could be determined which gives CPSA a fair reward for their diligence in pursuing the research.
  5. Alternatively - all non CPSA members can buy ASTM D5383-02(2003) Standard Practice for Visual Determination of the Lightfastness of Art Materials by Art Technologists and conduct your own tests in your home environment using blue wool cards.
I'm going to return to this topic with some regularity as I really do feel it is very important for all those artists using coloured pencils. Let's hope I have some good news to report next time.



Rose Welty said...

Katherine, you're scaring me here. But, it's right to be scared. Your idea about the prints is a good one.

Can you spill the beans on the better-than-average brand? :-)

Edition Handdruck said...

"My pinks, reds, crimsons, purples, violets, blues, lime greens and pale coloured greys were completely decimated."
Not really a surprise :). But is this really relevant ?
Did you calculate how long it would take until these colors fade visibly, maybe in 100 or 200 years ??

Edition Handdruck said...

I have spoken to Schmincke Laboratory.
They have a 5 star system. All colors with at least 3 stars will last under normal conditions i.e. framed and indoors about 25 years before fading starts. Reduction of UV light is the key ! A good uv-protection glass can elongate that period by factor 2- 4 ! Proper hanging i.e. not in direct sunlight etc. will do the same ! Colors with 4 and 5 stars go 100+ years. The trend goes to more and more lightfastness. But colors which are lightfast are less brilliant,so we loose those brilliant cadmium reds etc..
When you use colors with less than 3 stars you have to be aware that they can start fading within a couple of years.

Katherine said...

Rose - this may come as a bit of surprise for people but the one that did really well (in percentage terms) was Royal Talens Van Gogh. The fact that I have a supplier who sells single pencils from stock just down the road makes me feel very comfortable. I've always really liked them (they're very pigment rich) and I've now got another reason to like them even better!

Katherine said...

Rose - I forgot to say - it's maybe not surprising that Talens van gogh did so well. Like Derwent and Sanford they participated in the original work to develop the ASTM quality standard for coloured pencils. They've already invested in creating a product that meets the standard.

Five years after the standard was produced I'd very much like to see ALL manufacturers meeting the standard for pencils referred to as 'artist grade' - or at least telling us when they will be able to meet the standard.

Otherwise one has to question whether they can be fully justified in describing their coloured pencils as 'artist grade'.

Katherine said...

Martin - I do agree with you, the colours involved are hardly surprising!

However I think in this day and age we are all entitled to expect that some progress is being made in creating substances which enable a mark made by paint or pastel or coloured pencil to last more than 25 years!

Plus it would be good to know that where progress has been made with coming up with susbtitutes for the problematical pigments that progress is also being made with applying these to artist grade materials wich are sold in the marketplace.

To use an analogy, would you want your computer to be supplied with a chip from 15 years ago because it was 'the original' material used to produce a computer?

Remember also that Schminke pastels are also very pigment rich and the same might not apply to other brands.

The reason we have quality standards is so that we can measure manufacturers' claims for their product against a common standard so that materials become comparable.

So long as there is no standard for pastels or as long as manufacturers continue to fail to apply an industry standard (which ASTM effectively is) to the manufacture of their product then so far as I am concerned they are not delivering their best efforts to ensure that we as artists have a product that meets a minimum acceptable quality for products tagged as being 'artist grade'.

Perhaps of most concern is the fact that colours with a 2* rating or less can start fading a lot faster. I really don't think these should even be sold!

But then I've always been one of those people who's been very picky and used to stand for hours in art shops reading the star ratings on pastels before putting them on one side for purchase. So far as I'm aware I've never bought a pastel which is less than 3* and all the colours in my pastels are as bright as when they were first done.

But there's the rub - 'so far as I'm aware'. Bottom line for me is the overwhelming need for MUCH better information.

After all, these products are being used to produce paintings which are sold. Both artists and our customers deserve to know and be confident that the art isn't going to look faded in their lifetime. I've not come across an artist yet who subscribed to the artistic school of "planned obsolescence"!

Lisa B. said...

Excellent post. Can anyone be sure where a customer will hang a piece of artwork?

Belinda Lindhardt said...

As usual a fabulous post Katherine, i a few things for me made sense there which previously hadnt done in other articles :) Thankyou again

Laura said...

Another great post Katherine if very worrying. From one who makes a living from coloured pencil portraits this kind of information is invaluable.

Luckily I don't use reds, crimsons and purples and if I do only in small areas but even so I'd hate to think of a portrait I'd sold fading away in someones house. This information should really be made available to everyone and I wish the CPSA would sell it to non members - I'd definately buy one.

Katherine Tyrrell said...

Version 5 is now published and available from the CPSA website

It covers Derwent Coloursoft, Inktense and Graphitint amongst others

Anonymous said...

Thanks so much for this informative post. Lovely website and artwork. Thank you! --Joanne S., New York

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