When we say that an object is opaque, we mean that we are unable to view or recognize objects that are on the other side of it. Some objects are fully opaque, but some have a degree of translucency, which means that we can see through the object, but it is not completely transparent, or clear. Something like frosted glass would be considered opaque, which is not the same as a non-translucent object like wood.
Opaque items are colored by using lakes and pigments and the concentration of particles determine the level of opacity. The lower the concentration, the higher the level of translucency. When an object is dyed to be translucent, it allows more light to pass through, reflecting off the objects behind the surface and allowing them to reflect their own color wavelengths, increasing their visibility.