Test Card. Hydrus - top, Winsor & Newton - bottom.
I've started my permanence/lightfastness test today. As you can see from the image above I'm using 2 sets of primary colours; Hydrus Fine Art Watercolour by Dr. Ph. Martin's and Winsor and Newton Artist's Watercolour. I want to see if the Hydrus colours are lightfast, or at least as lightfast as the W & N colours.
On the bottles of Hydrus it says: Hydrus fine art watercolour is made from the finest artist's pigments which have been chosen for extreme lightfastness and brilliance. Hydrus gives to the watercolourist a new freedom to blend and intermix while maintaining the transparency and luminosity of the colour.
On the test card I've produced there are 6 stripes of paint, the top 3 Hydrus colours are: Cadmium Red, Hansa Yellow Light and Phthalo Blue. I diluted them by 2 drops of water to every 1 drop of liquid colour.
The Winsor and Newton colours are: Cadmium Red (rated A permanence, ASTM I.), Winsor Yellow (rated A permanence, ASTM I.) and Winsor Blue (Green shade) (rated A permanence, ASTM II.). Each of these were diluted to the same level as the Hydrus colours.
The test card is now standing in a south facing window with the "6 month" section only exposed. The rest of the card is securely covered with a very thick piece of grey card.
On the 21st October I'll expose the next section, along with the existing exposed area, and the final area will be exposed on 21st December. The test will end on 21st February.
I'd like to use the Hydrus colours to produce woodblock prints, but if the colours fade hugely then I'll stick to traditional tube watercolour. We'll see...