It is all in the “trans” when it comes to comparing transparency with translucence. Both terms describe objects that allow light waves to pass through, but the difference is vast, when it comes to being able to look at the substance or object and to actually see everything that is on the other side of the object.
Transparent objects provide no interference from flaws, distortions, reflective matter, or solid matter that would obscure the details of anything that is on the other side of the object. We can virtually see through a transparent object.
A translucent object contains some flaw, distortion, reflective action or enough solid matter so that objects on the other side might be visible, but are not clearly visible. (The term “opaque” means that nothing can be seen through a material or object).
The simple example of a pane of glass that is completely clear, without internal or surface flaws, dirt, or scratches will help. The perfect pane of glass offers an unimpeded view through the material, and is transparent. If we apply a very thin layer of oil, the view will be distorted by the refractive properties of the oil, but light and views will not completely blocked. If we apply a thin layer of oil that is impregnated with fine particles of solid matter, the view becomes increasingly obstructed as the light is partially blocked by the fine particles. If we apply glass etching material, the view will be completely blocked because the surface of the glass has been damaged by acid, but light will still pass through, making the pane of glass translucent.
In other words, light that would normally pass straight through the object is now sent into other directions by the introduction of solid or other substances that partially block or redirect the rays of light before it passes through.
Artists create the illusion of transparency and translucency by the above method, where solid grains of pigment are loosely suspended in clear oil or other mediums, and carefully spread over a very clearly defined image. In this way, the illusion of smoke, viewing a scene through distorted glass, or other illusions of translucency are created by introducing real translucency, or partial obscuring of light.
In a three dimensional object, such as a very bright opal that is encased in a translucent rock, or a light source that is encased in a translucent polymer, we see that light passes through from inside, or passes through, hits a reflective substance, and passes back through, but not as completely as it would if a very bright reflective substance or an internal light source were encased in a transparent substance.
Christmas time is the most excellent time for examining and studying transparency and translucence, as new creations of light and substance are brought out every year!