The creator of the website Welshpaintings, Robertson works in Snowdonia producing mainly watercolour landscapes of subtle beauty. He is taken with the effects of light on the land/sky interface and often paints looking into the sun when the whole scene is unified by a common recurrence of a particular hue, often a warm grey or cooler blue-grey. His pictures are infused with a certain transient quality emphasised by layer on layer of transparent colour, reflecting the ephemeral nature of the light-effects he paints. He also works in oil and acrylic using a bolder approach and more expressive brushwork.