It is not absolutely necessary to varnish a watercolour. Should extra protection be required, Talens watercolour varnish matt 050 can be used.
Granulation is a property of some pigments which refers to pigments in the paint combining together in small groups once applied. This produces a flocculated or curdled effect that brings life to the colour surface.
More about this in our blog 'Granulating colours'.
The fact that some colours remain on the paper and can only be partially washed away is due to the type of pigment (particle size) and/or the quality of the paper used.
More about this in our blog "Differences in drying of watercolour colours"
The bleeding technique is similar to the wet into wet technique (wetting your paper first with water, or painting into a wet area of color), only instead of laying your brush on the surface, let the color drip from above one into the next.
Tip – To control the bleed area, pre-wet only where you want the color to go first.
Ecoline and watercolour paint can be mixed without a problem, but whether this is wise depends on what you intend to do with the painting.
Read more in our blog 'Differences between Ecoline and watercolours'.