In Visible Emissions Smoke School -What is opacity?

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Opacity is the term used to refer to the blockage of light. In the old days I had a Kodak SLR 35 mm camera with an aperture that could reduce the amount of light going through the lens.

In visible emissions opacity refers to the amount of sunlight blocked by smoke or dust between the observers eyeball and the contrasting background on the opposite side of the plume.

In the old days the Ringelmann Chart was used to evaluate the density of a smoke plume. The chart was fool proof and fool hardy. The problem was that it only worked on black smoke.

When the government became concerned about white smoke and dust, they switched to the opacity theory. The opacity theory is based on the Ringelmann chart and 20% opacity is equal to number one on the Ringelmann chart.

This is my common man with a common van view of opacity. Opacity is when something gets in the way when you are trying to view something. For example you are trying to view the background- most cases a clear blue sky. In our smoke schools we often use green trees for a background because they give a contrasting background color on cloudy days. I have been trying 30 years to get our customers to plant giant 500 foot trees on top of a building near a smokestack. They just don't listen.

In common terms the smoke or dust gets in the way between you and the background. The smoke or dust reduces the visibility of the background. When you read the opacity focus on the background and not the smoke or dust.

My example of opacity. I am in my recliner relaxed, drinking a JAX Beer,

feet propped up. I am eating on a grape, a raisin, a pomegranate, a moon pie, Doritos, cheese dip, cheese grits, and an anchovy pizza. Singing Does your chewing gum loose its flavor on the bedpost every night.

The Saints are playing the Packers. It is the 4th quarter, the 2 minute warning. The Saints are winning by 2 touchdowns. Brett Favre is taking the snap from the center.

The wife Angie stands between me and the TV set hovering with the vacuum cleaner at 99 decibels. She vacuums between me and the TV, now that is 100% opacity, a complete blackout, and 100% frustration.

That ain't all. The Saints are winning by 2 touchdowns at the 2-minute warning. They will manage to somehow snatch defeat out of the arms of victory by letting Brett Favre score 3 touchdowns in 2 minutes. That is why some of us call them the Aints.