<PAGE>   1
                                                                   Exhibit 10.19

                              LASERTECHNICS, INC.
                              3208 COMMANDER DRIVE
                            CARROLLTON, TEXAS  75006

                                                                 January 8, 1998


To the Holders
listed on Schedule I
attached hereto:

                       PREFERRED STOCK EXCHANGE AGREEMENT

Dear Sirs:

                 This Agreement sets forth the terms and conditions on which
Lasertechnics, Inc., a Delaware corporation (the "Company"), and each of the
undersigned holders of record ("Holders") of shares (the "Series F Shares") of
Series F Preferred Stock, $.01 par value per share, of the Company (the "Series
F Preferred Stock") have agreed to the exchange of all the Series F Shares held
by such Holder for a combination of (i) shares (the "Series G Shares") of the
Series G Preferred Stock, $.01 par value per share, of the Company (the "Series
G Preferred Stock") and (ii) shares (the "Common Shares") of the Common Stock,
$.01 par value per share, of the Company.  A copy of the Certificate of
Designation for the Series G Preferred Stock, as filed with the office of the
Delaware Secretary of State, is attached hereto as Exhibit A.  The terms
"Series F Original Issue Price" and "Series G Original Issue Price" have the
meanings ascribed to such terms in the certificate of designations for the
Series F Preferred Stock and Series G Preferred, respectively.

                 1.       Exchange of  Preferred Stock.  (a)  Effective
immediately, each Holder hereby irrevocably agrees to exchange all the Series F
Shares held by such Holder for:

                          (i) the number of Series G Shares having an aggregate
                 Series G Original Issue Price equal to the sum of the
                 aggregate Series F Original Issue Price of the Series F Shares
                 so exchanged, plus the aggregate amount of all accrued unpaid
                 dividends on such Series F Shares (such sum, the "Aggregate
                 Face Amount Exchanged"); plus

                          (ii) a number of Common Shares equal to the Aggregate
                 Face Amount Exchanged divided by $1.00.

                 (b)  The table attached to this Agreement as Schedule I sets
forth the number of Series F Shares held of record and beneficially by each
Holder, the aggregate accrued unpaid dividends thereon, and the number of
Series G Shares and Common Shares to be issued by the Company to the Holder in
exchange therefor.  The Company and each Holder acknowledge and agree that
Schedule I is correct and shall be binding against the Company and each Holder
absent manifest error.
                 (c)  Certificates representing the Series F Shares held by
each Holder on the date hereof are hereby canceled, and, upon presentation of
the canceled certificate(s) to the Corporation,
<PAGE>   2
Preferred Stock Exchange Agreement
January 8, 1998
Page 2 of 3


each Holder shall be entitled to receive new certificates, representing in the
aggregate the Series G Shares and Common Shares issued to such Holder pursuant
to this Agreement.  From and after the execution and delivery of this
Agreement, certificates formerly representing Series F Shares shall represent
only the right to receive such new certificates as provided in this Agreement.

                 (d)  The Series G Shares and Common Shares issued to the
Holders in exchange for Series F Shares pursuant to this Agreement will not be
registered under the Securities Act of 1933, as amended, in accordance with one
or more exemptions from registration available under such act and the rules and
regulations of the Securities and Exchange Commission promulgated thereunder.
Certificates representing the Series G Shares and the Common Shares will bear a
restrictive legend substantially to the following effect:

                 "THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED
                 UNDER THE SECURITIES ACT OF 1933, OR APPLICABLE STATE
                 SECURITIES LAWS, NOR THE SECURITIES LAWS OF ANY OTHER
                 JURISDICTION.  THEY MAY NOT BE SOLD OR TRANSFERRED IN THE
                 ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER THOSE
                 SECURITIES LAWS OR PURSUANT TO AN EXEMPTION THEREFROM."

                 (e)  The Company hereby represents and warrants to each Holder
that the Series G Shares and Common Shares issued to such Holder hereunder are
duly authorized, validly issued, fully paid and non-assessable.  Each of the
parties to this Agreement hereby represents and warrants to each other party
that this Agreement has been duly authorized, executed and delivered by such
party and constitutes the legal, valid and binding agreement of such party,
enforceable in accordance with its terms.

                 2.       Miscellaneous.   This Agreement, including Schedule I
and Exhibit A attached hereto, constitutes our entire agreement with respect to
the subject matter hereof, and may not be modified or amended or any provision
hereof waived except by an instrument in writing signed by the Company and each
Holder.  This Agreement shall be binding upon and inure to the benefit of the
parties hereto and their respective successors and assigns.  This Agreement may
be executed in any number of counterparts and on separate counterparts, each of
which shall be an original instrument, but all of which together shall
constitute a single agreement.  One or more signature pages from any
counterpart of this Agreement may be attached to any other counterpart of this
Agreement without in any way changing the effect thereof.  This Agreement shall
be construed according to the laws of the State of Delaware.
<PAGE>   3
Preferred Stock Exchange Agreement
January 8, 1998
Page 3 of 3


                 If the foregoing correctly sets forth your understanding of
our agreement, please so indicate by signing and returning to the Company the
enclosed counterpart of this Agreement.

                                      Very truly yours,
                                      
                                      LASERTECHNICS, INC.



                                      By: /s/                                 
                                          ------------------------------------
                                          Name:
                                          Title:


AGREED and ACKNOWLEDGED
as of the date first written above:


ANTIOPE PARTNERS L.L.C.



By: /s/                                                
    ------------------------------
    A Managing Member



H.T. ARDINGER



By: /s/                                                 
    ------------------------------
    Name:
    Title:
<PAGE>   4
                                        PREFERRED STOCK EXCHANGE AGREEMENT
                                                  JANUARY 8, 1998

                                                        SCHEDULE I


<TABLE>
<CAPTION>
                                                               Aggregate
                             Number of         Accrued        Face Amount            Number of         Number of       
    Holders               Series F Shares     Dividends        Exchanged          Series G Shares    Common Shares  
    -------               ---------------     ---------       -----------         ---------------    -------------  
<S>                       <C>              <C>               <C>                <C>                 <C>             
Antiope Partners L.L.C.         48           $17,780.00       $497,780.00              50               497,780

H.T. Ardinger                   38           $19,573.00       $399,573.00              40               399,573
                                --           ----------       -----------              --               -------

               Total:           86           $37,353.00       $897,353.00              90               897,353
</TABLE>