Abstract:
Survey plat documents which are not susceptible to intentional alteration or damage due to environmental conditions are made using a photographic process. A transparent photographic film is exposed and photographically processed to capture the image of a plat drawing and then protected by applying clear laminates to each side of the film using a permanent, clear adhesive.

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
       [0001]    Not applicable. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates to survey plat documents. More specifically, the present invention relates to a composition and method for creating durable survey plat documents. 
         [0005]    2. Background of the Prior Art 
         [0006]    A survey plat is a plan or map of an area of land which is a proposed site for construction. More specifically, a survey plat is a map drawn to scale, showing the divisions of a piece of land. Given the value of real estate, the possibility of disputes related to ownership and boundaries and the needs of the Federal, State and local governments, plats must be carefully created and documented. Such documents must be preserved for many years. 
         [0007]    Many governments have enacted statutes regulating how plats are to be documented to ensure plat records are preserved. For example, Minnesota Statute 505.021 requires that a plat be prepared on 4 mil transparent reproducible film or the equivalent and that it be prepared by a photographic process. This statute also specifies the length and width of the sheet size of the plat document, specifically, 22 inches by 34 inches. This statute even regulates borders used on the document and how the sheets of multiple sheet plats are to be numbered. 
         [0008]    A number of problems exist when a photographic process is use to document plats. First, portions of a photographic image are susceptible to being scratched off the film bearing the image. This can occur due to normal wear. This can also occur as a result of purposeful efforts to alter the image. Second, it is often desirable to stamp the plat document with a date stamp, a notarial stamp, or the like. The ink used often does not bond well to film bearing the image of the plat resulting in smearing of the stamped information making it illegible. Third, government officials and others may find it necessary or desirable to make notations on the document. Also, such officials routinely sign such documents to make the documents “official”. The ink used to make such notes or to sign may not bond well to the image or film bearing the image causing the notes to smear. 
         [0009]    In view of the foregoing, there is a real need for survey plat documents and a process for creating survey plat documents which meet the requirements of the aforementioned statutes and which overcome the problems described above. 
       SUMMARY OF THE INVENTION 
       [0010]    A survey plat document meeting all of the requirements of such statutes and overcoming the above-described problems includes a base layer comprising a polyester film which has been coated with a light-sensitive photo emulsion coating. After the photo emulsion coating has been exposed and processed so that it bears an image of a platdrawing, a matte laminate is applied to the front and back of the film using a permanent adhesive. The matte laminate may be made of polyvinylchloride (PVC) and serves not only to protect the image on the film, but also serves as a substrate which is receptive to the inks typically used to stamp, sign or make notes on survey plat documents. 
         [0011]    The process used to create such survey plat documents begins by creating a plat drawing on wide format paper which conforms to the applicable legal requirements. The plat drawing must then be transferred to a reprographic service bureau, otherwise referred to herein as a “photo processor”. This can be done by sending the original drawing to the photo processor or by scanning the drawing to create a digital file, such as a jpeg or PDF file, and sending the digital file to the photo processor. If a digital file is sent to the photo processor, the photo processor will print the image in the digital file onto wide format paper complying with the statute. 
         [0012]    Next, a reduced size photographic negative of the original or printed drawing is created. If the negative contains any unwanted images, they are removed from the negative. Using the negative and a camera, the image is projected onto the light-sensitive photo emulsion coating of the durable clear polyester film. After the film is exposed, it is processed by submerging the film in a photographic developer tank, then in a chemical fixative tank and finally into a wash tank. The film is then dried. 
         [0013]    After the film has been dried, a transparent laminate is applied using a clear, permanent adhesive to both the front and back of the film. The laminates have a matte finish comprising a notation (drafting) tooth receptive to ink. The composition is then trimmed to size to yield a composition which fully complies with the statute. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description with references to the following drawings in which like numerals in the several views refer to corresponding parts. 
           [0015]      FIG. 1  is a top view of a survey plat document; 
           [0016]      FIG. 2  is a cross-section of the survey plat document of  FIG. 1 ; 
           [0017]      FIG. 3  is a partial side view of a laminate having a notation (drafting) tooth. 
           [0018]      FIG. 4  is a flow chart showing a process for creating the survey plat document of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    This description of the preferred embodiment is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top” and “bottom”, “under”, as well as derivatives thereof (e.g., “horizontally”, “downwardly”, “upwardly”, “underside”, etc.) should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “connected”, “connecting”, “attached”, “attaching”, “joined”, and “joining” are used interchangeably and refer to one structure or surface being secured to another structure or surface or integrally fabricated in one piece unless expressly described otherwise. 
         [0020]      FIGS. 1 and 2  show a survey plat document  1  made in accordance with the present invention. The survey plat document  1  includes opposing left and right side edges  2  and  3 , as well as opposing top and bottom edges  14  and  15 . The top edge  14  and bottom edge  15  are 22 inches apart and the left edge  2  and right edge  3  are 34 inches apart. These dimensions may be altered without deviating from the invention, but are employed in the embodiment shown to conform with the Minnesota Statute referenced above. 
         [0021]    The survey plat document  1  also has front and back surfaces  4  and  6 . Front surface  4  and back surface  6  will be spaced so the survey plat document is 4 mil thick to conform with the Minnesota Statute. Again, other thicknesses may be employed without deviating from the invention. 
         [0022]    The survey plat document  1  comprises a base layer  8 . Base layer  8  is a thin, clear polyester film such as a biaxially-oriented polyethylene terephthalate film (BoPet). BoPet materials are sold by DuPont under the brand name “Mylar”. The base layer  8  has a first face  100  and a second face  102 . Applied to face  100  of the base layer  8 , to form together with the base layer  8  a photo-sensitive film  104 , is a light sensitive photo emulsion coating  9 . An example of such a coating is a composition comprising light sensitive crystals, such as silver halide crystals, dispersed in gelatin. Various companies including Agfa and Fuji sell films such as film  104 . When the coating  9  of the film  104  is exposed to light, the light sensitive crystals are activated. When the film  104  is then processed, an image such as  16  will appear on the clear film  104 . 
         [0023]    The survey plat document  1  includes two clear (transparent) adhesive layers  10  and  11 . Adhesive layer  10  permanently couples the film  104  to a first laminate  12  which forms the front  4  of the plat document  1 . More specifically, adhesive layer  10  permanently bonds the laminate  12  to the coating layer  9  to sandwich the coating layer  9  between the laminate  10  and the base layer  8 . 
         [0024]    Adhesive layer  11  permanently couples face  102  of base layer  8  to a second laminate  14  which forms the back of the plat document  1 . 
         [0025]    The first laminate  12  and second laminate  14  are each made of a clear polymer film having a matte finish. The laminates  12  and  14  may come with the adhesive layers  9  and  11  pre-applied. In such cases, the laminates  10  and  12  are supplied with a paper backing which is removed at the time the laminates  10  and  12  are applied to the film  104 . The laminates  12  and  14  are made of a material and with a finish that allows the laminates to receive and bond with the inks used on stamps such as stamp  17 , and signatures and notes written on the document with a pen such as  18 . For this purpose, the front and back surfaces  4  and  6  each have a “notation tooth” (sometimes referred to as a “drafting tooth”) finish. As illustrated in  FIG. 3 , the front  4  of laminate  10  has a plurality of interstices  200  which provide this matte, notation tooth finish. 
         [0026]    Since preserving the image of the survey plat drawing from harm is of primary importance, the photo emulsion coating  9  selected should be resistant to the damaging effects of ultraviolet (UV) and other forms of light which, in the early days of photo processing, were known to cause fading of photographic images. Many suitable photo emulsions are now available. For added protection against fading of the image  16  due to exposure to light, a UV inhibitor may is imbedded either in the laminates  12  and  14  or in the adhesive layers  10  and  11 . 
         [0027]    In most cases, the primary purpose of the laminates  12  and  14  is to protect the image from other environmental conditions which may damage the image  16  or from intentional or accidental scratching away of portions of the image. Using two such laminates allows the survey plat document  1  to lay flat and keeps the survey plat document  1  from curling. The laminates  12  and  14  are made of a non-porous polymeric material such as polyvinylchloride (PVC). This material also offers the advantages of being able to accept and bond with the inks which would be typically used to apply stamps such as  17  or signatures and notes such as  18  to the front  4  of back  6  of the survey plat document  1 . Such a laminate is made by Oracal USA and sold under the designation Oraguard  290 M. 
         [0028]    A process for producing the survey plat document is illustrated in  FIG. 3 . The process starts at step  20  by collecting the survey information necessary to prepare a drawing of the plat. At step  22 , a plat drawing is created on a standard piece of paper, preferably sized to conform to the applicable government regulations. If convenient to do so, the drawing created at step  22  may be transferred to a photo processor as represented by the arrow from step  22  to step  30  in  FIG. 4 . 
         [0029]    Alternatively, the drawing created in step  22  can be scanned using a digital scanner or camera to create a digital file of the plat drawing, as shown at step  24 . The digital file may be in any suitable file format, such as jpeg, PDF or TIFF. A native raw file format could also be used. At step  26 , the digital file is transferred to the photo processor. This can be done by attaching it to an e-mail or uploading it to a server where it can be retrieved by the photo processor. The digital file is then printed onto wide format paper which conforms to the applicable governmental regulations related to size and boarders at step  28 . 
         [0030]    The paper print created at step  28  is then photographed at step  30  to create a photographic film negative. This may be done using a computer-controlled camera/projector. In some instances, for example due to dust on the camera lens or sensor, there may be imperfections on the negative. The negative is then examined at step  32  and any unwanted images on the film negative are removed by opaquing them from the negative. 
         [0031]    At step  34 , the same camera/projector may be used to project the image onto film  104  and, more specifically, the light sensitive photo emulsion coating  9  on the polyester base layer  8 . The film  104  is then processed at step  36 . 
         [0032]    Processing step  36  includes substeps  38 - 44 . At step  38 , the film  104  is submerged in a tank containing a photographic developer solution which brings out the image, such as image  16 , on the film. The film  104  is then submerged in a tank containing a chemical fixative at step  40  to stop the chemical reaction between the developer solution and the emulsion coating  9 . At step  40 , the film  104  is submerged in a washing tank to wash away the excess developer and fixative from the film. The film  104  now comprising and bearing an image such as image  16  is removed from the washing tank and then dried at step  44  by running them through a dryer. Alternatively, the film can be hung in a suitable manner and left to dry. 
         [0033]    Once the film  104  bearing image  16  is dry, step  46  is performed. More specifically, a laminate  12  is applied to the front  100  of the film  104  using a permanent adhesive  10 . Laminate  12  is applied over the photographic emulsion coating  9  so that the photographic emulsion coating  9  and the image  16  formed by the coating are sandwiched between laminate  12  and base layer  8 . A laminate  14  is applied to the face  102  of the base layer  8  of the film  104  using a permanent adhesive layer  11 . The two laminates  12  and  14  may be made of the same material. Both should be moisture impermeable, durable and suitable to project the film  104  and image  16  from scratching, normal wear and environmental conditions. Since the base layer  8  is transparent in most cases, both of laminates  12  and  14  (or alternatively the adhesive layers  10  and  11 ) may be impregnated with a material that will preclude damaging wavelengths of light (e.g. light in the ultraviolet range) from reaching the image  16  so the image  16  is not degraded by such light. Impregnating the laminates or adhesive layers with such a material will not be necessary if a suitable photo emulsion is used to form the coating  9 . As noted above, the laminates  12  and  14  have a matte finish. This will serve to prevent glare in some light conditions making the information contained in image  16  easier to read. The finish is also characterized as having a notation tooth or drafting tooth finish to provide surfaces  4  and  6  which may be written upon or stamped. 
         [0034]    At step  48 , the survey plat document  1  is trimmed to the correct size. The process is finished at step  50  and the survey plat document  1  is ready for submission to the government or stored. It is during this step  50  that stamps such as  17  and signatures and notes such as  18  are applied to the front surface  4  or back surface  6 . 
         [0035]    Throughout this specification, terms such as “clear” and “transparent” have been used. Thus, terms reference the fact that the materials or structures referred to permit enough light of wavelengths in the visible range to pass therethrough to permit the image  16  to be viewed. From the foregoing, those skilled in the art will recognize that the materials and structures may be adapted to block light of other wavelengths, such as ultraviolet light, which could damage the image. The materials chosen must permit the image on the film  104  to be viewed through laminate  12 , and in some cases, laminate  14 , and the adhesive layers  9  and  11  used to bond these laminates to film  104 . 
         [0036]    The foregoing description is intended to explain the various features and advantages, but is not intended to be limiting. The scope of the invention is defined by the following claims which are also intended to cover a reasonable range of equivalents.