articles/Photoshop/botanicalart-page3
by Mike McNamee Published 01/10/2007
Watercolours - a special case
Watercolours are a common subject for reproduction and require particular care for really accurate work. One of the key things that distinguishes a watercolour from other art is the way the qualities of the paper are exploited by the artist. Generally the highlights in the picture are created by not putting paint in that area. This is aFlower pictureccomplished by either careful brushwork or by protecting the surface with masking solutions such as Maskol. This is a rubber-based masking fluid which is painted in the highlight areas then removed at the completion of the picture. If they make a mistake, the artist is faced with either 'scratching back' the highlights or applying china white - both are potential pitfalls for reproduction as they might expose the camera or scanner to a metameric pigment or base.
In a nutshell, here is the problem when reproducing watercolours. Take, as an example, a delicate botanical illustration by professional illustrator, Margaret Stevens FSBA. Margaret, the president of the Society of Botanical Artists, has painted the image (right) on a cream watercolour paper.
The troublesome Cadmium reds and oranges. The as-scanned, profiled and then the hand-corrected red is shown inside the white marker.
No, we are not on the snooker table, we are talking red pigments! Lukman had experienced some difficulty in reproducing the popular pigment 'cadmium red'. Differentiating between subtle changes of tones with these reds had been a particular problem with differences in originals not being reflected by differences in the prints made from scans. We decided to investigate in some detail. Lukman painted a set of swatches for analysis and these were measured using a spectrophotometer and then measured again after a variety of scanning options. The colours chosen were Windsor and Newton's, Cadmium Orange, Cadmium Red, Alizarin Crimson, and a final swatch that was a mixture of the last two.
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