before the present methods are described it is to be understood that this invention is not limited to the particular methods , compositions and experiments described herein . moreover , it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting , as the scope of the present invention is to be defined only by the appended claims . by “ shrinkage ” is meant decrease in width of film when the film is exposed to processing temperatures of the polymer melt inherent to the method described and claimed herein . in one embodiment , “ shrinkage ” may be described as decrease in width of the film when the film is exposed to high temperatures of , for example , greater than 100 ° c .). by “ specular ” is meant capable of reflecting light like a mirror , having the qualities of a mirror and capable of providing an image of objects . by “ substantially free of distortion ” or “ low distortion ” is meant that the likeness of the image reflected by the mirror is substantially identical to the naturally occurring image so reflected therein . polymeric substrates suitable for use in the invention include any polymeric material such as acrylic from which a sheet product may be produced by calendering , including , but not limited to the following : copolymers of polyalkylene terephthalate ( e . g . copolymers of terephthalic acid or esters thereof with any of the following : i ) napthalene dicarboxylic acid or esters thereof ; ii ) isophthalic acid or esters thereof ; iii ) phthalic acid or esters thereof ; iv ) alkane glycols ; v ) cycloalkane glycols ; vi ) alkane dicarboxyl ! c acids ; and vii ) cycloalkane dicarboxylic acids ; polyethylene naphthalate ( pen ) and isomers thereof ; copolymers of polyethylene naphthalate ( pen ) including those of the ( 2 , 6 -, 1 , 4 -, 1 , 5 -, 2 , 7 -, and / or 2 , 3 - naphthalene dicarboxylic acids , or esters thereof , with any of the following : i ) naphthalene dicarboxylic acid or esters thereof ; ij ) isophthalic acid or esters thereof ; iii ) phthalic acid or esters thereof ; iv ) alkane glycols : v ) cycloalkane glycols ; vi ) alkane dicarboxylic acids ; and vii ), cycloalkane dicarboxylic acids ; polycarbonate resins including acrylonitrile butadiene styrene resins , polystyrene , syndiotactic polystyrene , syndiotactic polyalpha - methyl styrene , syndiotactic polydichlorostyrene , copolymers and blends of the foregoing styrenes ; styrene copolymers such as styrene butadiene copolymers and styrene acrylonitrile copolymers , 4 . 4i - dibenzoic acid and ethylene glycol ; polyacrylates such as polybutylacrylate and polymethylacrylate ; and polyimides such as polyacrylic imides and polyether imides ; substituted and unsubstituted vinyl polymers and their copolymers ; and other polymers processed by calendering including polyvinylchloride ( pvc ) as well as blends of two or more of the foregoing polymers or copolymers . in one embodiment of the invention , a film is first metalized and subsequently laminated by a calendering roll process to a molten polymeric substrate as the substrate is extruded . films suitable for metalization include , but are not limited to , pmma and its copolymers , polycarbonate , cyclic olefin co - polymers ( coc &# 39 ; s ) pet , polystyrene , and polyethylene terephthalate glycol ( petg ) as well as mixtures and combinations thereof . metalization of the film is typically accomplished either by depositing from plasma or vapor sputtering , such techniques being well known in the art . preferably the thickness of the film before metalization is from about 0 . 001 inch to about 0 . 005 inch . selection of the film is critical to the success of the lamination . if the film has too much shrinkage , the smooth mirror surface becomes distorted and can take on a matte appearance . a film shrinkage of less than about 2 % is optimal to maintain good mirror optics . ( i . e . impact modified pmma which has been metalized via vacuum deposition produced a laminated product with a dull matte appearance while the original film demonstrated a bright , highly reflective mirror finish .) a dull matte finish results when the film width shrank approximately 20 %. trials with various pet based films have yielded similar results where shrinkage of the film when exposed to elevated temperatures (& gt ; 100 ° c .) is less than 2 %. in another embodiment of the invention , a reflective film composed of multiple very thin layers is provided . because of the combined index of refraction and thicknesses , such a reflective film provides the appearance of a colored mirror and is bonded to the polymer substrate . in a particular embodiment , the reflective film may be composed of about 300 to about 400 layers and has a total thickness of about 0 . 001 inch to about 0 . 002 inch . films greater than 0 . 002 ″ thickness tend to cause the extruded polymer sheet to develop unacceptable warpage , e . g . greater than about 0 . 4 or 0 . 5 inches per foot . the thickness of the substrate acrylic also influences the degree of warpage . a thicker substrate is less susceptible to the warping effect . to improve adhesion to the acrylic or polymeric substrate , the reflective film , whether metalized or not , may be treated with an adhesion promoting coating , heat - seal or a primer , to further ensure bonding to the substrate . the manufacturer typically does application of such a coating and its use is a known and accepted technique in lamination . however , when compatible polymer films are chosen for the substrate and the mirrorized film or colored film nearest the substrate , no adhesion promoter may be necessary or in some instances , only treatment of the film surface by corona discharge or plasma is required prior to lamination . the following illustrative examples are presented to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use some particular articles and methods of the invention . a series of four films were applied to an acrylic sheet 2 mm in thickness by feeding the films over the second roll of a three or four roll calendar system into a bank of melt of polymethylmethacrylate . the bank of melt was adjacent to the roll over which the film was run . optionally , the melt bank could be adjacent to the opposite roll , but better results are achieved if the bank of melt is adjacent to the roll over which the film is fed . tension was applied to the film to remove and prevent the formation of wrinkles . a mirrorized polyethylene terephthalate type material which had a heat activated adhesive applied by the manufacturer over the mirrorized surface was provided as a film having a width of 24 ″. excellent adhesion and optics were achieved . some small dimples or point distortions were noted in the metalized film . adjusting temperatures of the calendar rolls could eliminate these defects . a film was provided that had been treated by a corona discharge system . the roll was 48 ″ wide . the film itself adheres to the sheet with no further treatment . excellent optical appearance was achieved . again , small dimples could be eliminated with adjustments to the calendar roll temperatures . excessive calendar roll temperature was found to cause an unacceptable hazy appearance to develop . results similar to film number 2 above as describing the treated color mirror . results similar to film number 2 above as describing the treated color mirror . in all cases it is critical to find the optimum calendar roll temperatures and speeds to prevent the development of optical defects in the mirror lamination . it was found that with the treated color mirror in point 2 the first 2 calendar rolls had to be run between 79 ° c . and 82 ° c . to prevent the formation of large round distortions in the film . at temperatures above the 82 ° c . level these defects occurred with increasing frequency as the temperature increased ( highest temperature tried was 90 ° c . on the second roll ). the temperatures of the 3rd and 4th rolls were also critical to maintaining good appearance . if the fourth roll was maintained more than 2 ° c . hotter than the third roll the laminated film developed a very hazy appearance . the same could be caused by operating the 3 rd and 4 th rolls at surface speed difference greater than 1 %.