Liquid on the Surface to Enhance Colour?

My fascination with the colour of oil slicks on roads or pavement surfaces is something I wanted to experiment with, perhaps producing something that is even better than flip paint, or that compliments it well. I thought about different liquid substances that could be poured over a sculpture during the exhibition, that would then react with light to produce an oil-slick effect, more colour enhanced than anything I have done before. I knew that this idea of having liquid continually pouring over sculptures was going to take a lot of labour-intensive calculation and specialist equipment (if I didn't want to just have a tank dripping slowly from above, without flowing back into itself) This idea would also have health and safety implications - however I was adamant to explore it in case it could be possible.

A Little bit about Pavement Oil Slick Rainbows:

"When petrol is dropped on the road during a rainy day, a thin layer of oil will appear on the water surface. Both the top and bottom surfaces of this oil film can reflect light. If the path difference between two light rays is an integral times of the wavelength, there will be constructive interference (SEE DIAGRAM). A light ray will pass through different thickness of oil when the angle of reflection varies. The wavelength corresponding to the constructive interference also differs and this causes the reflected light to have various colours. As a result, a rainbow-like colour pattern is shown on the oil surface and this phenomenon is called thin-film interference."

Essentially, the rainbows we see are dependant on:

- Light hitting the oil and water in a very specific way.

- Dark colour on surface.

It might be possible for me to create the look of a rainbow or some kind of iridescent liquid, using the pigments I bought for use in my printmaking (instead of working with oil, water and light).

Experiment 1: SUNFLOWER OIL & SWEET VIOLET SHIMMER PIGMENT.

I like how thick this appears, but it doesn't look that great flowing over the surface of black expanding foam. It is too yellow but the consistency is perfect.

Experiment 2: WATER & SWEET VIOLET SHIMMER PIGMENT.

I really like the way that this pours over the surface of the sculptures, although the shimmer pigments stick to the surface which might not make it as effective as I'd hoped (it had it's best moment when it is first poured). If the liquid was oil based, maybe it would have worked.

It was suggested to me to try baby oil or clear mineral oil with the added pigment to see how that works. At this stage it's probably more practical to conquer what I'm actually going to make first, then revisit this later.

The images below FAR LEFT & RIGHT is experiment 2. The middle image is just a FAIL. (water, oil and blue transparent resin pigment).