Subtractive filter for the printing of color photographic film
First Claim
1. A subtractive filter assembly for the printing of color photographic film comprising three individually adjustable elementary filter portions through which the light to be filtered passes, each of the three elementary filter portions comprising:
- a fixed cylindrical central portion having at its center a channel for the passage of the light and a radial milled slot on its surface;
a rotary ring positioned concentrically with said fixed cylindrical central portion, said rotary ring having a graduation on its circular periphery and having an internal surface comprising a logarithmically progressive ramp;
a filter holder comprising a frame adapted to slide in said radial milled slot in said fixed cylindrical central portion, said frame having a top and bottom, said bottom of said frame having the shape of a rounded point which abuts said ramp, said top of said frame having a spring which rests against said receiving part;
said frame of said filter holder having an upper portion comprising a window opening and a lower portion comprising a filter element;
whereby the positioning of said rotary ring operates to position said filter holder within said radial milled slot to regulate the amount of light passing through said filter element.
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Accused Products
Abstract
A subtractive filter having three elementary filters, each comprising a fixed cylindrical central portion having at its center a channel for the passage of the light and on its surface a radial milled slot; a rotary ring concentric to the said fixed cylindrical central portion having a graduation on its central periphery, the inside of said rotary ring having the shape of a logarithmically progressive ramp; and a filter holder comprising a frame adapted to slide in the said radial milled slot in the fixed cylindrical central portion, the bottom of said frame having the shape of a rounded point which rests against said ramp and the top of said frame having a spring resting against a part fastened to the periphery of the fixed central portion, said frame of said filter holder comprising at its top a window opening and at its bottom the filter. Regulation of light passing through each of the three filters is accomplished by rotating the rotary rings.
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Citations
11 Claims
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1. A subtractive filter assembly for the printing of color photographic film comprising three individually adjustable elementary filter portions through which the light to be filtered passes, each of the three elementary filter portions comprising:
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a fixed cylindrical central portion having at its center a channel for the passage of the light and a radial milled slot on its surface; a rotary ring positioned concentrically with said fixed cylindrical central portion, said rotary ring having a graduation on its circular periphery and having an internal surface comprising a logarithmically progressive ramp; a filter holder comprising a frame adapted to slide in said radial milled slot in said fixed cylindrical central portion, said frame having a top and bottom, said bottom of said frame having the shape of a rounded point which abuts said ramp, said top of said frame having a spring which rests against said receiving part;
said frame of said filter holder having an upper portion comprising a window opening and a lower portion comprising a filter element;whereby the positioning of said rotary ring operates to position said filter holder within said radial milled slot to regulate the amount of light passing through said filter element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A subtractive filter assembly for the printing of color photographic film comprising a plurality of individually adjustable filter portions, each of said filter portions comprising:
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a fixed central portion having a central aperture, a forward surface and a rearward surface, said forward surface comprising a slot, a filter holder located movably within said slot, said filter holder comprising a bottom contact portion, a light transmitting portion and a colored light filtering portion adapted to be moved across said central aperture; a rotatable ring concentrically located relative to said fixed central portion, said rotatable ring comprising an internal surface, said internal surface comprising a curved ramp portion which engages said bottom contact portion of said filter holder and causes said filter holder to move within said slot such that said light transmitting portion and said colored light filtering portion are moved across said central aperture as said rotatable ring is rotated; means for biasing said filter holder such that bottom contact point is biased into engagement with said curved ramp;
said curved ramp having a first point located at a distance from the center of said rotatable ring such that when said bottom contact portion is located at said first point said colored light filtering portion substantially covers the entirety of said central aperture and a second point located at a distance from the center of said rotatable ring such that when said bottom contact portion is located at said second point substantially all of the light passing through said central aperture passes through said light transmitting portion,whereby the degree of light filtered by each adjustable filter portion is regulated by the rotation of the corresponding rotatable ring.
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Specification