How to make a platypus swim - "Afloat" WIP3-5

How do you make a platypus swim? Or how do you make a water animal appear as though it is partly submerged in the water?

After fiddling with the background and gel effects (see previous post for work in progress shots), it was finally time to add detail to the platypus in my painting "Afloat". But the question remained - how was I going to make it appear as though the platypus was submerged partly in the water, and swimming along?

Reflections and sharp focused 'shiny' highlights: These are an obvious component to making an object appear 'wet'. Both wet and glossy surfaces have the characteristic that when light shines on them, instead of being diffusely scattered (and hence causing a wide dull highlight), the light is reflected back in a close to parallel fashion. This means that wet objects typically have distinct areas of 'shine' or 'glint' similar to the glint in animal eyes which shows they are alive. You can see how as soon as these highlights are added to the head of the platypus in WIP 3, it starts to appear somewhat more 'alive'.

Trapped bubbles in fur: Water-submerged fur tends to trap bubbles when a mammal first gets wet (or if it has an especially thick water-repelling coat), and these bubbles tend to be highly reflective. The bubbles tend to form patterns which make streaks along the animal's body, in the direction of travel through the water. I've attempted this effect with the lighter patterns down towards the platypus' back.

Darker, duller and refracted underwater light: Light that travels to our eyes from an object underwater is often distorted (depending on the variable density of the water particles caused by waves or ripples above it), and somewhat darker and more neutral in colour than objects above water. This is because water is a more dense medium than air, and tends to scatter light differently to air. In the case of my platypus, the water was relatively clear, and the surface was unruffled (so the submerged parts of the platypus still appear roughly in proportion), however, the water adds a mild dullness to the submerged parts (WIP 4). I've achieved this by adding dark but transparent washes of colour on the submerged parts.

Boundaries and interfaces: Furthermore, light tends to refract more at boundaries between media, such that there can be an interface line between the two parts of a partly submerged object. You can see this effect especially at the shoulder of the platypus in WIP 4, where the water meets the above water highlights. I've achieved this simply by adding a thin white line.

Three dimensional effects: An additional technique I decided to try in this painting to enhance the effect of the platypus being partly submerged was to varnish the whole piece (except the above-water parts of the platypus) with liquid gloss which provides a 2mm thick layer of clear glossy varnish over the painted background. This gloss also sometimes contains bubbles (through the mixing process - it comes as a two-part epoxy resin), and this can add to the effect of the water. When photographed at a steep angle to a light source, you can see where the liquid gloss interfaces with a satin varnish that I've used to coat the above-water parts of the platypus (see WIP 5a - platypus detail).

So there you have it! The platypus now swims! :)