How to tell which Winsor & Newton colours are lightfast

All Winsor & Newton colours show a rating for Permanence on their packaging. This rating informs the user on all factors relating to the Permanence of colours which incorporates lightfastness . The permanence of an artists' colour is defined as ‘its durability when laid with a brush on paper or canvas, graded appropriately and displayed under a glass frame in a dry room freely exposed to ordinary daylight and an ordinary town atmosphere'. This definition reflects the way in which we expect to find paintings displayed. During this testing, we use accelerated tests for lightfastness, test for binder stability in addition to information provided by our pigment suppliers.

Winsor & Newton ratings are therefore a combination of the natural passage of time, accelerated tests and pigment manufacturers' testing and development and are the most stringent in the industry. These ratings are printed on the tube and can be seen in our composition and permanence tables. Read here for more information on ratings and what they mean.

Additionally, many of Winsor & Newton’s colours are tested for ASTM ratings. ASTM stands for American Society for Testing & Materials, which has set standards for the performance of art materials including a colour's lightfastness. To measure lightfastness using this system, colours are reduced to a level of 40% reflectance by the addition of Titanium White, (except for water colour which relies on the white paper). This means the amount of light reflected from the colour swatch. The swatches are then tested in both sunlight and artificially accelerated conditions. You can find out more on ASTM ratings here.

As not all colours have been tested for ASTM, it is recommended that the Winsor & Newton permanence rating (which is the comprehensive rating for evaluating colour for factors including lightfastness), should be used to indicate a colour's ability to resist fading.