Differential Reduction Printer (Patent No: 625049)

Inventor: Glazier, Walter H.

Location: Calgary

Comments: N/A

Description: THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A differential printer for processing seismic sections which comprises; means for holding the negative of the print to be processed; means for holding a photographic sensitive medium parallel to the negative; a first opaque screen and a second opaque screen, said screens being parallel to said negatives and each screen having a narrow slit with the slits being at right angles to each other.
2. A differential reduction printer for processing seismic section for making a photographic print from a negative in which one dimension of the print is enlarged or reduced in comparison to the other dimension of the print which comprises; means for holding said negative in a fixed position; means for holding a photographic sensitive medium parallel to arid spaced from said negative; a first opaque screen parallel to said negative and spaced between said negative and said photographic sensitive medium, said first opaque screen being characterized by having a narrow horizontal slit across the center thereof; a second opaque screen spaced between said first opaque screen and said photographic sensitive medium, said second opaque screen having a narrow slit at right angles to the slit in said first opaque screen.
3. An apparatus as defined in Claim 2, which includes a light source of uniform intensity and of greater area than said negative, said light source being on the opposite side of said negative from said screens; and a mask between said light source and said negative, said mask being a negative of the density variation of said negative.
4. An apparatus as defined in Claim 2, in which one of said slits is curved.
5. An apparatus as defined in Claim 2, in which one of the slits is bent.
6. An apparatus for making variable density seismic depth sections from variable density seismic time sections which comprises: means for holding a negative of the time section in a fixed position; means for holding a photographic sensitive medium parallel to and spaced from said negative; a first opaque screen parallel to said negative and spaced between said negative and said photographic sensitive medium, said first opaque screen being characterized by having a narrow horizontal slit across the center thereof; a second opaque screen spaced between said first opaque screen and said photographic sensitive medium, said second opaque screen having a narrow vertical slit across the center thereof; a light source of uniform intensity over an area at least as large as said negative and spaced from said negative on the opposite side thereof from said screens; means for exposing a narrow horizontal section of said negative with the horizontal section exposed moving from the top to the bottom of said negative; means for adjusting the position of first said screen during the exposure of said negative in which the first said screen is moved at a function of time determined by the velocity of the depth of the section being exposed.
7. An apparatus as defined in Claim 6, in which the slit in said first screen is curved.
8. A differential reduction printer for processing a seismic section for making a distorted photographic print of a negative which comprises: means for holding said negative in a fixed position; means for holding a photographic sensitive medium parallel to and spaced from said negative and aligned therewith; a first opaque screen parallel to said negative and spaced between said negative and said photographic sensitive medium, said first opaque screen being characterized by having a narrow horizontal slit across the center thereof; a second opaque screen spaced between said first opaque screen and said photographic sensitive. medium, said second opaque screen having a narrow slit at right angles to the 1it in said first opaque screen; means for exposing said negative by sweeping with a narrow band of light; means for moving one of said plates during the exposure of said negative, the instantaneous position of said plate being a function or the distortion desired for the segment of the negative then exposed.