Trees, rocks, opaque walls
That situation is pretty much the norm, since there's no such thing as an "opaque color".
All three ; the front is a mix of transparent & translucent and the back (where the photo-receptor dyes are) is opaque.
Gouache.
There are many objects that no light can pass through, although of course, it depends on what type of light you're talking about. The name of the type of object that visible light cannot pass through is called opaque.
gouache
This is referred to as an opaque overhead projector, or sometimes simply as an "opaque projector." This is in contrast to the regular overhead projector which must have transparencies to project, an opaque projector can project an image of opaque objects such as the paper pages of a book.
The scientific term for an object that does not let light through is "opaque." Opaque objects do not allow light to pass through them and therefore block the transmission of light.
Aluminum foil is opaque.
The three degrees of crystal diaphaneity are transparent (light passes through easily), translucent (light passes through but objects can't be seen clearly), and opaque (light does not pass through).
Opaque
The scientific term for an object that does not let light pass through is "opaque." Examples of opaque objects include metals, wood, and thick plastics that block the transmission of light.
The material is referred to as an electorchromic material.