ASTM Pastel Lightfastness Standard D8330-20

This will interest all pastel artists - specifically those who are interested in the lightfastness of pastels and the new technical standard for how lightfastness is tested.

I've been a long-time proponent of lightfastness which is how I got involved in how lightfastness standards are developed and the testing involved. 

I first wrote about the development of a lightfastness standard for pastels back in 2010 - in A Lightfastness Standard for Pastels: current status. As a result of this I was invited to become a member of the ASTM Subcommittee D01.57 on Artist Paints and Related Materials - albeit have never made it to a meeting since they've traditionally been held in the USA! I stuck to commenting from a distance!

This was followed by a second post - ten years ago(!) - called UPDATE! Standard Specification for Artists Pastels

Finally the Standard was published in 2020 - but for some reason passed me by at the time! Maybe other things were happening!!

Below you will find two videos, produced by the International Association of Pastel Societies (IAPS),  about the new (in 2022) Lightfastness Standard for Pastels published by the American Society for Testing and Materials - now better known as ASTM International.

The Visual Appearance of Light Testing Results - from the video talk by Michael Skalka
from left to right: the colour not exposed to light, the colour exposed indoors, the colour exposed outdoors

ASTM D8330-20: Standard Specification for Artists’ Pastels

Below are two videos - made in 2022 - which comment on the process and the technical aspects of testing for lightfastness.

• the first is a talk by the man who has been responsible for steering all the lightfastness standards on art materials
• the second is a discussion between Council Members of IAPS about how they were involved with the process of developing the standard

IAPS ASTM Pastel Standard (54 minutes) - this lengthy video has an explanation by my good friend Michael Skalka,  the longtime Chair of ASTM Subcommittee D01.57 on Artist Paints and Related Materials, about 

• the rationale for the development of the Lightfastness Standard
• the benefits of the Standard
• addressing criticism of the Standard
• plus a demonstration of some of the test results across different colours (which accounts for why I got heavily involved with lightfastness well over 15 years ago - when I saw the same results for coloured pencils using different pigments!)
• plus a visual summary of the test results - which highlighted which pigments did very well and why dyes used for pastels produced very poor results
• Conclusions about the overall process - highlighting the lack of engagement by both manufacturers and artists

Since Michael retired from his work in Conservation at the National Gallery in Washington, he's started a website called The Syntax of Color and I wrote about Michael and new developments in Michael Skalka knows about art materials!

IAPS ASTM (11 minutes)

The second is a "talking heads" video which focuses more on the ongoing relationship IAPS had with ASTM in the development of the standard over many years.

A conversation with IAPS Materials team - Richard McKinley, Shirley Anderson and Susan Weber about the ASTM pastel lightfastness standard.

The IAPs developed an Art Materials Team and have worked together with ASTM - to help finish the testing and build a bridge between the artists and the manufacturers.

Note: You can read current news from IAPS here. This INCLUDES an article about ASTM and Lightfastness of Pastels.

My own informal testing process

I have my very own lightfastness tests going on, on the walls of my home.

I have to say that, compared to other media (notably coloured pencils), I am very impressed with the quality of colour of artworks produced using Unison Pastels.