(1) A small, unwanted, transparent area in the developed emulsion of a negative or black area on a positive; usually due to dust or other defects on the copy, copyboard glass or on the film (2) In paper, small imperfections caused by foreign matter on its surface during papermaking to top
an occluder with small holes that is held over the patients own glasses to see if their vision improves The pinhole gives the sharpest vision possible and gives an idea of what vision would be like if the patients glasses were changed
A vertical hole running through the middle of the insulator It may or may not extend all the way through the insulator and may or may not be threaded Designed to receive a pin or bracket See also: Threaded Insulator, Threadless Insulator
1 A small clear spot on a negative usually caused by dust on the film during exposure or development or by a small air bubble that keeps developer from the film during development
A pinhole is a tiny hole. a very small hole in something, especially one made by a pin
This artifact is defined as a bare spot on the surface of the polarizer such that light can pass through without being polarized This type of artifact impacts contrast but is not visible in transmission