Transparency halation measurement method and apparatus

A method of recording a calibration standard for measuring halation in a transparency, comprising the steps of:

• (a) projecting light from a light source toward a lens of a camera;
• (b) interposing a filter in the light path between the source of said light and said lens of said camera such that direct light from said light source is occluded from said camera lens, said filter having a central opaque portion with a plurality of rings concentrically encircling said central portion and diminishing in opacity the greater distance each ring is from said central portion;
• (c) photographing an image of said filter on film in said camera;
• and
• (d) producing a photographic print of said filter image for use as a calibration standard in which the contrast between various rings of said plurality of rings of said filter is readily visible on said print.

Apparatus for measuring halation in a transparency comprising:

• (a) a light source positioned on one side of a transparency for projecting light through a given test region of said transparency;
• (b) a camera disposed on the opposite side of said transparency, said camera containing photograhic film and having a lens aligned with said light source for receiving light which passes through said transparency test region to produce an image on said film within said camera;
• and
• (c) a filter interposed in the light path between said light source and said camera lens, said filter serving to occlude from said camera lens the direct light from said light source such that an image of halation present in said test region of said transparency outside the periphery of said filter may be recorded on said photographic film of said camera.