Definition - What does Presentation Layer mean? The presentation layer is layer 6 of the 7-layer Open Systems Interconnection (OSI) model. It is used to present data to the application layer (layer 7) in an accurate, well-defined and standardized format. The presentation layer is sometimes called the syntax layer.
As shown in the next figure, an object is seen as black if it absorbs all colors of white light. A white object reflects all colors of white light equally. If an object absorbs all colors but one, we see the color it does not absorb. The yellow strip in the following figure absorbs red, orange, green, blue, indigo and violet light. It reflects yellow light and we see it as yellow. The eye also uses complementary colors in color vision.
A black light is a source of electromagnetic radiation that emits near-ultraviolet light, usually in the 350-375 nanometer wavelength range. This range is just slightly below the 400nm that human eyes can detect. When this light is reflected off certain materials, it looses energy and its wavelength expands to over 400nm. The reflected light is then visible to human eyes, and the illuminated objects appear to glow.