US3685900A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure calculator and filter device for darkroom color photography
Assignee: KMS Industries Inc
•
Filing: 1970-02-12
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Granted: 1972-08-22
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Expires: 1990-02-12
Abstract
Abstract Calculator for determining proper exposure times in making color prints from color negative films comprises an opaque mask with three series of windows having respectively blue, green and red filters of graduated density. The windows have double wedge shape to provide contiguous points and other points remote therefrom. Color print paper is test exposed to light passing through the negative, a diffusion filter, and the graduated filters; when the paper is developed, the correct exposure time is indicated on the paper by the faintest double wedge image which has sharply defined points. A filter device for use in conjunction with the calculator comprises a wheel rotatably mounted on the lens barrel of a projector and having a series of openings: one clear for focusing, one with a diffusion filter for the test exposure, and the others with blue, green, and red filters respectively.
Inventors
- 👤 Herbert D Kirby
- 👤 George L Nearhoof
- 👤 Jimmie Glenn Culler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:52
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/007; G01; G01J; G01J1/00; G01J1/42; G01J1/4209; G01J1/4214; G03; G03B; G03B27/00; G03B27/72; G03B27/73; G01J1/02; G01J1/04; G01J1/0488; G01J1/0492
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
65 words
An exposure calculator for color photographic emulsions which comprises, a substantially opaque member having three series of windows therein, means providing the windows of said series respectively with red, green, and blue filters of graduated density, each of said windows having a portion which tapers acutely and terminates substantially at a point, and means providing exposure duration indicia correlated to the densities of said filters.
Claim 2
Dependent Claim
65 words
An exposure calculator for color photographic emulsions which comprises, a substantially opaque member having three series of windows therein, means providing the windows of said series respectively with red, green, and blue filters of graduated density, each of said windows having a portion which tapers acutely and terminates substantially at a point, and means providing exposure duration indicia correlated to the densities of said filters.
Claim 3
Dependent Claim
18 words
The calculator defined in claim 1 wherein each of said windows has a plurality of said taper portions.
Claim 4
Dependent Claim
24 words
The calculator defined in claim 1 wherein each of said windows has two of said taper portions which are opposed with their points contiguous.
Claim 5
Dependent Claim
51 words
The calculator defined in claim 1 wherein each of said windows has two sections each of which has a said taper portion, said sections being opposed with their points contiguous, each of said sections having two other portions which taper acutely and terminate substantially at points remote from said contiguous points.
Claim 6
Dependent Claim
33 words
The calculator defined in claim 1 wherein said calculator is adapted for use in combination with a projector having a diaphragm adjustable to various f/stops, said graduated densities being correlated to said f/stops.
Claim 7
Dependent Claim
31 words
The calculator defined in claim 5 wHerein adjacent ones of said densities are so related as to correspond to a variation of about one-third of an f/stop of a said diaphragm.
Claim 8
Dependent Claim
26 words
The calculator defined in claim 1 wherein said densities are in the range of from about 0.02 to about 2.00 on the standard Density Transmittance Table.
Claim 9
Dependent Claim
38 words
The calculator defined in claim 1 wherein said densities are graduated in a step-by-step manner, the density difference between adjacent steps being in the range of from about 0.01 to about 0.11 on the standard Density Transmittance Table.
Claim 10
Dependent Claim
31 words
The calculator defined in claim 1 wherein said means providing each of said filters comprises a colored translucent element secured in laminar relation with a gray translucent element having graduated density.
Claim 11
Dependent Claim
14 words
The calculator defined in claim 9 wherein said colored element has substantially uniform density.
Claim 12
Dependent Claim
27 words
The calculator defined in claim 9 wherein said opaque member has transparent portions providing said windows, said elements being secured in laminar relation with said transparent portions.
Claim 13
Dependent Claim
28 words
The calculator defined in claim 11 wherein each of said elements comprises a strip which spans the length of the series of windows with which it is associated.
Claim 14
Dependent Claim
70 words
The calculator defined in claim 12 wherein said series extend substantially parallel to each other and the windows thereof are in laterally aligned groups of three, said gray element having three longitudinally extending portions, each of which has densities which are graduated in a step-by-step manner along its length, said three portions respectively overlying said three series with the steps thereof in registry with the windows of the respective series.
Claim 15
Dependent Claim
20 words
The calculator defined in claim 11 wherein said opaque member and said translucent elements comprise exposed and developed photographic films.
Claim 16
Dependent Claim
38 words
The calculator defined in claim 13 wherein said indicia comprises a series of numbers on said opaque member extending substantially parallel to said series of windows, said numbers being laterally aligned respectively with said groups of three windows.
Claim 17
Dependent Claim
34 words
The calculator defined in claim 14 wherein said films are secured to a supporting frame which defines three slots each exposing one of said three series of windows so that light can pass therethrough.
Claim 18
Dependent Claim
31 words
The calculator defined in claim 16 wherein said frame also has an open area, said opaque member having a transparent portion extending across said open area and providing a writing surface.
Claim 19
Dependent Claim
40 words
The calculator defined in claim 17 wherein said frame has another open area, said opaque member having a portion which extends across said other open area and which has transparent regions defining numerals, said numerals providing said exposure duration indicia.
Claim 20
Dependent Claim
88 words
In combination with the calculator defined in claim 1, a filter device which comprises, means forming a holder having a series of openings within which are mounted respectively a diffusion filter, a blue filter, a green filter, and a red filter, mounting means adapted to be mounted on the lens barrel of a projector with which said calculator and filter device are adapted to be used, said mounting means movably supporting said holder so that said filters can be moved successively into alignment with the lens barrel axis.
Claim 21
Dependent Claim
64 words
The combination defined in claim 19 wherein said holder is in the form of a wheel pivotally secured to said mounting means with said series of openings extending circumferentially with respect to the axis of the pivotal mount, said mounting means comprising a ring adapted to be mounted around a lens barrel, said ring being substantially coaxial with a filter rotated into alignment therewith.
Claim 22
Dependent Claim
27 words
The combination defined in claim 20 wherein said series includes a fifth opening through which an image can be focused on a photographic plane by the projector.
Claim 23
Dependent Claim
31 words
The combination defined in claim 20 wherein said wheel carries phosphorescent indicia for each of sAid filters, said indicia being disposed substantially diametrically opposite the pivotal mount from the respective filters.
Claim 24
Dependent Claim
46 words
The calculator defined in claim 1 wherein said opaque member has transparent portions providing said windows, said windows having graduated gray densities, and a colored translucent element secured in laminar relation over each of said series and cooperating with said gray densities to provide said filters.
Claim 25
Dependent Claim
17 words
The calculator defined in claim 23 wherein said member and elements comprise exposed and developed photographic film.
Claim 26
Dependent Claim
28 words
The calculator defined in claim 1 wherein said opaque member has translucent portions providing said windows, said windows being colored and having graduated densities to provide said filters.
Claim 27
Dependent Claim
19 words
The calculator defined in claim 25 wherein said member and windows therein comprise an exposed and developed photographic film.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-22 | 1976-02-21 | 1976-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-22 | 1980-02-21 | 1980-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-22 | 1984-02-21 | 1984-08-22 | $7700.00 | Window Closed / Lapsed |