PDA

View Full Version : characteristics of pigment - using acryl and watercolor


satsumas
01-08-2019, 12:40 PM
Hi eveyone! Im new to this and hope you can help!

I was wondering whats the benefit of knowing the characteristics of each pigment when using acryl and watercolor?


I understand that in oil its good to know the drying time as one example. But whats the benefit of knowing the each pigment characteristics for acryl and watercolor?

Best Regards

WFMartin
01-08-2019, 01:23 PM
In watercolor, I was often concerned with different pigments in terms of their staining power, and flocculation (a kind of clumping of pigment particles), and granulation.

Understanding the characteristic some pigments have for staining is important because those colors are not easily "lifted" (removed) by a mere re-wetting, and light scrubbing with a brush.

Other than that characteristic, I was usually most concerned with the transparency vs. opacity of the various pigments. Those characteristics really have their places in watercolor painting.

RomanB
01-08-2019, 01:29 PM
1. Pigments have various lightfastness in different media. It is good to know that you are using pigments that would last 100 years without changing much. Modern industry of organic pigments makes this task harder than ever since most of organic substitutes are less lightfast than the best inorganic pigments.

2. Pigment strength is very important. You could have a drop of Ultramarine Blue and a drop of Prussian Blue watercolour paints and while Ultramarine will behave as expected, pure Prussian Blue is a monster which colours everything around.

3. In acrylics pigment to binder ratio is poor, so many pigments are not saturated and opaque even in maximal concentration.

4. In watercolours pigments demonstrate some unique properties like staining (how much pigment could be scrubbed after application) or flocculation (how pigment interacts with paper surface relief and other pigment particles)

5. Some pigments cannot be used in some media while are beneficial in others. For example, there is no Lead White watercolour at all, but in oil it is magnificent.

6. Two pigments of same apparent color sometimes behave differently in mixtures.