One can be opaque in a number of ways. It can refer to transparency, a person's ability (or lack thereof) to see through things. It can also mean difficult to understand. In both instances its root meaning is closely related to perception and understanding.

In the origins of Impressionism there was a concept that had began to take root prior to the popularization of the art genre, the concept of the flaneur:

"Flâneur (French: [flɑnœʁ]) is a French noun referring to a person, literally meaning "stroller", "lounger", "saunterer", or "loafer", but with some nuanced additional meanings (including as a loanword into English)." (Wikipedia)

A wanderer, hardly noticeable, walking the streets of a city....

The Opaque Impressionist is a collection of instrumental Doom / Stoner Metal that presents Stoner as modern flaneur, traversing landscapes urban and desert, challenged by altered perception both imbibed and organic. This album was largely inspired by these impeccable albums as well as too many more to name.

This album has been inspired by:
-Orange "Heavy Rocks" by BORIS
-Phase 3: Thrones and Dominions by EARTH
-Primitive & Deadly by EARTH
-The Sciences by SLEEP
-Weedsconsin by Bongripper
-Dopethrone by Electric Wizard
-Dead Roots Stirring by Elder
-What We All Come to Need by Pelican

For their inspiration I thank them. For those who listen I say thank you as well.

"The concept of the flâneur is important in academic discussions of the phenomenon of modernity. While Baudelaire's aesthetic and critical visions helped open up the modern city as a space for investigation, theorists such as Georg Simmel began to codify the urban experience in more sociological and psychological terms. In his essay "The Metropolis and Mental Life", Simmel theorized that the complexities of the modern city create new social bonds and new attitudes towards others. The modern city was transforming humans, giving them a new relationship to time and space, inculcating in them a "blasé attitude", and altering fundamental notions of freedom and being:

The deepest problems of modern life derive from the claim of the individual to preserve the autonomy and individuality of his existence in the face of overwhelming social forces, of historical heritage, of external culture, and of the technique of life. The fight with nature which primitive man has to wage for his bodily existence attains in this modern form its latest transformation. The eighteenth century called upon man to free himself of all the historical bonds in the state and in religion, in morals and in economics. Man's nature, originally good and common to all, should develop unhampered. In addition to more liberty, the nineteenth century demanded the functional specialization of man and his work; this specialization makes one individual incomparable to another, and each of them indispensable to the highest possible extent.

However, this specialization makes each man the more directly dependent upon the supplementary activities of all others. Nietzsche sees the full development of the individual conditioned by the most ruthless struggle of individuals; socialism believes in the suppression of all competition for the same reason. Be that as it may, in all these positions the same basic motive is at work: the person resists being leveled down and worn out by a social-technological mechanism. An inquiry into the inner meaning of specifically modern life and its products, into the soul of the cultural body, so to speak, must seek to solve the equation which structures like the metropolis set up between the individual and the super-individual contents of life."
Simmel, Georg (1950). "The Metropolis and Mental Life". In Weinstein, D. (ed.). The Sociology of Georg Simmel. Translated by Wolff, Kurt. New York: Free Press. pp. 409–424.