However, this conjecture may not be correct. This summer in the UK, although I cannot produce figures to support my observation, there have been many more wet days than the long-term average, but the total rainfall during the past few months has been below average. This apparent anomaly can be explained by pointing out that there has been a lot of mizzle this year. If you’re not familiar with this term, it is a portmanteau word for a type of rain that is intermediate in character between mist and drizzle.
Clearly, heavy rain will wash away a stain very quickly (and the pollutants will end up in the local river system), but mizzle merely provides a thin layer of water upon which any pollutants can float, so stains remain in situ for longer than is usual, which explains why I’ve seen so many this summer. Colour Field Analysis, which I posted in June, was the result of a mere ninety-minute stroll around town, and two days ago, I took almost forty photos on a similar walk (some of these are featured below).
The lighter and more volatile hydrocarbons, such as petrol and diesel, provide the most colourful pictures. Engine oil, by contrast, produces only a silvery blue smear. There are several different types of stain. The commonest type is what I refer to as an undisturbed point source. These appear to have come from stationary vehicles, and a good example is The Wow Factor:
The title of this photo refers to the way I came across it. It occurred at the entrance to a busy roundabout, and as I was crossing the road my attention focused on seeing if there was any traffic coming. When I turned to face the direction in which I was walking, this stain was right in front of my feet, prompting me to utter a not-so-silent ‘wow!’ and reach for my camera.
Another type of stain involves a fairly substantial amount of pollutant, which appears to have come from a moving vehicle. The next photo is a good example:
Large amounts of pollutant can get spread out over time by the wheels of other vehicles, as seen in the next photo:
A rare form is shown in the next photo: an actual river of petrol. The vehicle leaking this petrol must have been haemorrhaging it by the gallon. This photo was taken directly in front of my house.
The remaining photos show more variations on the point-source theme, with additional comments where appropriate.
The title of this photo references a track on Jethro Tull’s classic 1971 album Aqualung.
The title of this photo references a track on Deep Purple’s 1972 album Machine Head. Smoke on the Water describes a notorious incident during a Mothers concert in 1971 in which a member of the audience fired a flare into the roof. It contains the following words:
Frank Zappa and the Mothers
Had the best place around.
But some stupid with a flare-gun
Burned the place to the ground.
I see hints of Indian iconography in this image, although others may not.
In case you don’t understand the title of this picture, it’s staring you in the face. This photo appeared in the ‘yourpics’ section of the BBC News website on 27th January 2016.
Finally, here are three images to which I have not given titles, mainly because I couldn’t think of anything appropriate. You might like to suggest suitable ones.
On a technical note, you will not be surprised to learn that oil stains don’t look like any of these photos. I use Microsoft’s Picture Manager to crop the images to a standard shape, then to crank up the contrast and the colour saturation and finally to reduce the brightness. However, if colours are not visible in an oil stain before it is photographed, then no amount of manipulation will produce the colours you see here. All that will result is a fuzzy blue haze, hints of which can be seen around the edges of some of the images above.