Tuesday, February 20, 2007

Colourfastness in coloured pencils

Coloured Pencils: Brazilian Lightfastness Test
(Jan. 2006 - Jan. 2007)

(click the image to see a larger version and check the brand and pencil no.)
Colours exposed to Brazilian daylight for a year on the left;
colours preserved in conditions without light on right

Lucio Rubira is a 43 year old comics artist and professional illustrator living in São Paulo Brazil. He uses coloured pencils both for his job and his own personal artwork (see below) and given the strong light found in Brazil is particularly interested in the quality and lightfastness of material used for his own artwork.

Lucio recently posted a thread about a year long colourfastness test he has been conducting on the Wet Canvas Colored Pencil Forum. This involved testing the lightfastness of Prismacolors, Polychromos and Pablo coloured pencils of similar colours (see above) in identical light conditions and against a control chart of colours kept away from all light for the duration of the test.

Hong Kong 2005
coloured pencil
copyright Lucio Rubira

I invited Lucio to contribute to my blog about his test and he sent me larger versions of his colour charts than those available on the forum. For details of how the tests were conducted see Lucio's explanation below. As you can see the colours most affected are Prismacolor 1013 (Deco Peach) - which has completely disappeared - and Prismacolor 1028 (Blue Slate).
Colourfastness in Colored pencils

Lots of CP artists are concerned about the colorfastness of their colored pencils. As CP artwork once sold may not be framed and exposed to light to museum standards we all need to be careful to avoid any pencils that fade when exposed to light. I work mainly with Pablo from Caran D´ache and Faber Castell's Polychromos, but I got some samples of Sanford's Prismacolors to put them side by side in a small test.

I made two color charts on Fabriano 4 acid free paper using a Prismacolor pencil and then and the nearest colours to that using two other brands (Faber Castell Polychromos and Caran d'Ache Pablos - with Stabilo pencils used to fill some gaps). I put one chart in a drawer inside a black envelope. I attached the other chart to a window and it was exposed to intense daylight for one year from January of 2006 to January of 2007. This wasn't direct sunlight but it was tropical sunlight as I live in São Paulo, Brazil.

I am a illustrator and my works are scanned and later they rest in a dark place safe almost forever. However, if I produce work which is going to be displayed (eg a portrait) I am very concerned with the resistance of colors to light. Imagine a baby portrait made with a lot of Deco Peach ( Prismacolour 1030 ) I would have a disaster in a couple of years of inappropriate exposure to bright daylight!

I think the color comparison is self explanatory. I have to say that if the test was made with the charts protected with good fixatives and/or UV glass it's likely that the results would be different. Some UV glass has a protection factor of more than 90% . Ordinary thick glass will also probably help to protect the more fragile colors.
Traditionally, the colours which tend to be most robust when exposed to light are browns. Those that are most fugitive are pinks, purples and all light shades. Sanford recognised the very serious problem it had with its Deco colours and has now introduced a set of lightfast pencils. I understand that it has also withdrawn all those colours which caused the most problems in terms of lightfastness - which includes all the deco colours. It's certainly the case that they are no longer listed as part of the Premier Pencil range by Sanford - although Blue Slate (1024) is still listed and maybe its inclusion should be reviewed again?

Lucio goes on to comment.....
Serious artists have considerable difficulty at times making sure they are working with top quality products. The colored pencil makers usually rate the colorfastness of the pencil in the body of the pencil but some times we have to search their websites to find what the information means.
I agree with Lucio that it would be a huge bonus for all serious CP artists if all the coloured pencil manufacturers were to make good quality and detailed techinical information about lightfastness easily accessible on their websites and using universal technical terms and standards. I'm not clear at the moment which manufacturers are signed up to the new lightfastness standard.

If you have not already done so, I recommend that you should:
  • review lightfastness information supplied by manufacturers
  • identify pencils which don't have a good lightfastness rating
  • go through all your pencils and separate out all those which don't have good lightfastness ratings and/or are no longer listed as being supplied by the manufacturer. In general, colours withdrawn are those which are now recognised to be fugitive.
  • Unless you only produce prints and don't sell originals and/or keep artwork in sketchbooks you should now chuck all the pencils with fugitive colours. If you're being really rigorous get rid of all those except the most lightfast.
  • make sure all your future pencil buys involve pencils with good lightfastness ratings.
You might also want to take a look at the new lightfastness module within my squidoo lens "Coloured Pencils: Resources for Artists". This includes all the links I can find to information about lightfastness in coloured pencils which is independent of that provided by the manufacturer. It includes:
  • all known links to the websites of coloured pencil manufacturers - including a new link (hurrah - found it last!) to the Royal Talens Van Gogh lightfast pencils.
  • an explanation by Bet Borgeson of a simple way in which you can test your coloured pencils in your own home and
  • an example from another artist, Sarah Longrigg, of her own test on black paper (over a two and a half year period). Her test was conducted at her home close to the West Highland Way in Scotland - a bit of a difference from São Paulo Brazil!
An exercise still needs to be done comparing watercolour pencils with artist pencils - as dilution with water generally impairs lightfastness when pigments are less than the best.

In the meantime, Lucio also tells me that if any manufacturers would like to engage him to test any of their existing or new coloured pencil products in Brazilian sunlight and would like to send him pencils to try he'd be very happy to oblige! Lucio can be contacted either by leaving a comment on this blog post or via me.

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3 comments:

Belinda Lindhardt said...

Thanks for this Katherine I have actually been trying to read up on this lately and find it very confusing to know whats what. Your post has cleared the air a bit :)

Martin said...

Hello
these selfmade tests are always of very limited value and hardly of any practical relevance as the amount of UV-A received by the colors is not measured. The important question is how much UV-A light gets on your piece of art at the place of hanging. What is the situation in a normal indoor environment ? Did you ever get a sunburn in your living room? What about flowers, why do we place them near the window ?
Only a small fraction of natural UV-light gets through a standard glass window. If you have thermo glass even less. Depending on the hanging situation the amount of uv-light is reduced even more. Normally the work is framed under glas or even museum glas and the amount of UV-A is reduced again.Very quickly the factor of reduction comes to 1% or even less.How much time of the year do we live under artificial light ? In other words you would have to wait about 100 years to have a similar effect indoors that you might have in 1 one year on a rooftop in Sao Paulo.
One can expect that today`s artists quality pencils will last indoor, properly framed and not exposed to direct sunlight several generations. If these works get into a museum they will come under professional light management and will exist much longer.
So I think there is no reason to get in panic about your colored pencils and start the big sorting out.If you chuck out all "fugitive" colors as recommended you will end up with a very limited dark selection of earth colors.

Katherine said...

Martin - thank you for your comment.

Some points by way of response:
* first Lucio's chart was not fixed to a roof top in Brazil. I'm not quite sure why you thought this. As he indicated in the post, the chart was attached to a window and experienced tropical light but NOT direct sunlight.
* Lucio's concern arose from the fact that not everybody may frame a work 'properly' although I'm sure we would all agree this is to be recommended and does offer a greater degree of protection
* you may not be aware that various other tests which have been conducted by CPSA and Sanford have established that certain colours in the Prismacolor range which used to be on sale are definitely fugitive (eg all the Deco colours) and have already been withdrawn from sale although they may still be found in retailers. At the same time Sanford has released a new lightfast range which I understand is proving very popular.

I'm recommending that people get rid of colours which have been established to be fugitive if they want to sell original art.

Information is available from CPSA and others who have conducted tests in strict (blue wool) test conditions about the level of lightfastness displayed by different colours. There are some very lightfast colours which are not browns. I've provided the links for that information if you'd like to take a look.

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