AMENDMENT TO
                    LOAN AGREEMENT AND RELATED LOAN DOCUMENTS


     This  AMENDMENT  dated  as of  this  third  day of  December,  1998 to Loan
Agreement dated December 18, 1996, as amended by Amendment to Loan Agreement and
Related  Loan  Documents  dated  February  6,  1998,  (as  amended,   the  "Loan
Agreement")  and to the Loan  Documents (as defined in the Loan Agreement and as
amended to date), is by and among PRESSTEK,  INC., a Delaware corporation with a
principal place of business at 8 Commercial Street,  Hudson, New Hampshire 03051
(the  "Borrower"),  DELTA V TECHNOLOGIES,  INC., an Arizona  corporation  with a
principal  place of  business at 7775 North Casa Grande  Highway,  Tucson,  Pima
County, Arizona 85745 (the "Guarantor"), and CITIZENS BANK NEW HAMPSHIRE, a bank
organized  under the laws of the State of New Hampshire with a place of business
at 875 Elm Street, Manchester, New Hampshire 03101 (the "Bank").

                                   WITNESSETH:

     WHEREAS,  the Bank has extended a certain  revolving line of credit loan to
the   Borrower  in  the   principal   amount  of  up  to  Ten  Million   Dollars
($10,000,000.00)  (the "Revolving  Line of Credit Loan") and a certain  mortgage
term loan to the  Borrower in the  principal  amount of Six Million Nine Hundred
Thousand  Dollars  ($6,900,000.00)  ("Term Loan") pursuant to the Loan Agreement
and certain Loan Documents; and

     WHEREAS, the Borrower has requested,  and the Bank has agreed, to (1) renew
the Revolving Line of Credit Loan, (2) decrease the interest rate  applicable to
the  outstanding  principal  under the  Revolving  Line of Credit Loan,  and (3)
modify  certain  provisions  pertaining to the  Borrower's  financial  covenants
contained  in the  Loan  Agreement,  all  upon  and  subject  to the  terms  and
conditions of the Loan Agreement and the Loan Documents, as the same are amended
hereby.  All  capitalized  terms not  otherwise  defined  herein  shall have the
meanings  ascribed to them in the Loan Agreement  and/or the Loan Documents,  as
the case may be.

     NOW,  THEREFORE,  in consideration of the premises  contained  herein,  the
Borrower, the Guarantor, and the Bank hereby agree as follows:

          1.   AMENDMENT OF LOAN AGREEMENT.

          A. The first  sentence in  Paragraph  I. C. of the Loan  Agreement  is
     amended to read as follows:

          "The  Revolving Line of Credit Loan shall be subject to review and, at
          the sole option and discretion of the BANK,  renewal on July 31, 2000,
          and, if renewed,  thereafter on each  subsequent  anniversary  of such
          date  (July  31,  2000,  and each  anniversary  thereof  to which  the
          Revolving Line of Credit Loan is renewed, being a "Review Date")."


<PAGE>



          B.  Paragraph  I. D. of the  Loan  Agreement  shall be and  hereby  is
     replaced in its entirety with the following:

         "D.  Interest Rate. The principal  balance of each Advance  outstanding
         from time to time under the Revolving Line of Credit Loan shall, unless
         BORROWER otherwise elects the Prime Rate (as defined below) to apply to
         such Advance,  bear interest during the Advance Term (as defined below)
         therefor  at a fixed rate equal to the LIBOR  Rate (as  defined  below)
         plus one and one-half  percent  (1.5%) per annum.  As used herein,  for
         each Advance the term "LIBOR Rate" shall mean the rate as determined by
         the BANK on the basis of the offered rates for deposits in U.S. dollars
         for a thirty (30) day period which appear on the Telerate  page 3750 or
         Reuter's  LIBOR page as of 11:00 a.m.  London  time on the date that is
         two (2) Banking  Days  preceding  the first day of the Advance Term for
         such Advance. If such rate does not appear on the Telerate page 3750 or
         Reuter's  LIBOR page,  the rate for that date will be determined on the
         basis of the offered  rates for  deposits in U.S.  dollars for a thirty
         (30) day period  which are  offered  by four major  banks in the London
         interbank  market at  approximately  11:00 a.m. London time on the date
         that is two (2)  Banking  Days  preceding  the first day of the Advance
         Term for such Advance.  The principal London office of each of the four
         major BANKS in the London interbank market will be requested to provide
         a quotation of its U.S.  dollar  deposit  offered rate. If at least two
         such  quotations  are  provided,  the rate for  that  date  will be the
         arithmetic  mean of all such  quotations.  If fewer than two quotations
         are provided as requested, the rate for that date will be determined on
         the basis of the rates  quoted  for loans in U.S.  dollars  to  leading
         European  BANKS for a thirty (30) day period  offered by major BANKS in
         New York City at  approximately  11:00 a.m., New York City time, on the
         date  that is two (2)  Banking  Days  preceding  the  first  day of the
         Advance Term for such Advance. In the event that the Board of Governors
         of the Federal Reserve System shall impose a Reserve  Percentage on the
         BANK with  respect to LIBOR  deposits of the BANK,  then for any period
         during which such Reserve  Percentage shall apply, the LIBOR Rate shall
         be equal to the amount determined above divided by an amount equal to 1
         minus the Reserve  Percentage  actually  maintained by the BANK. In the
         event of any such imposition of a Reserve Percentage,  the BORROWER may
         elect by written notice to the BANK to have the entire principal amount
         of all  outstanding  Advances  bear  interest  at the  Prime  Rate  (as
         hereinafter defined).  For purposes hereof,  "Reserve Percentage" means
         the rate  (expressed  as a decimal)  at which the BANK is  required  to
         maintain  reserves under  Regulation D of the Board of Governors of the
         Federal  Reserve System  against  Eurodollar  liabilities  outstanding.
         Interest  shall be calculated  and charged daily on the basis of actual
         days elapsed over a three  hundred  sixty (360) day banking  year.  The
         "Advance  Term"  for each  Advance  shall be a thirty  (30) day



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<PAGE>



          period  beginning  on the Banking Day elected by the BORROWER for such
          Advance to be made. BORROWER shall notify BANK in writing at least two
          (2)  Banking  Days in  advance  of the date upon  which  the  BORROWER
          desires the Advance to be made. BORROWER's notice to BANK as aforesaid
          shall specify the amount  requested to be advanced under the Revolving
          Line of Credit  Loan and the date such  Advance  is to be made  (which
          must  be  a  Banking  Day).  The  entire   principal  amount  of  each
          outstanding  Advance  shall  either be repaid in full as of the end of
          the  Advance  Term   therefor  or,  if  not  repaid  in  full,   shall
          automatically  (and without  requirement  of written  notification  by
          BORROWER)  be deemed a new  Advance as to which (i) the  Advance  Term
          shall  commence as of the next day after last day of the Advance  Term
          then ending and (ii) the interest  rate  therefor  shall be equal to a
          fixed  rate  equal  to the  LIBOR  Rate  as of two  (2)  Banking  Days
          preceding the first day of such new Advance Term plus one and one-half
          percent (1.5%) per annum. As used herein,  the term "Prime Rate" shall
          mean the rate  published by The Wall Street  Journal from time to time
          under the  category  "Prime  Rate:  The Base Rate of  Corporate  Loans
          posted by at least 75% of the  Nation's 30 Largest  Banks" (the lowest
          of the rates so  published  if more than one rate is  published  under
          this category at any given time) or such other  comparable  index rate
          selected by the BANK in its sole discretion if The Wall Street Journal
          ceases to publish such rate. The BORROWER  acknowledges that the Prime
          Rate is used  for  reference  purposes  only  as an  index  and is not
          necessarily the lowest interest rate charged by the BANK on commercial
          loans.  Each time the Prime Rate changes the  interest  rate under the
          Revolving Line of Credit Loan shall change contemporaneously with such
          change in the Prime Rate.  Interest  shall be  calculated  and charged
          daily on the basis of actual days elapsed over a three  hundred  sixty
          (360) day banking year."

          C. Paragraph 1. of Section VII. Q. entitled "Additional  Financial and
     Other  Covenants"  shall be and hereby is replaced in its entirety with the
     following:

          "1.  Borrower  shall  have a  Tangible  Capital  Base (as  hereinafter
          defined)  equal  to  at  least   Seventy-Two   Million  Eight  Hundred
          Forty-Five Thousand Dollars ($72,845,000.00) as at July 4, 1998, which
          Tangible Capital Base requirement shall be measured and increased (but
          never, in any event decreased) on a cumulative basis as at each fiscal
          quarter  end  thereafter  by  an  amount  equal  to  the  sum  of  (a)
          seventy-five  percent  (75%) of  Borrower's  net  income for each such
          fiscal quarter and (b) the amount of equity capital proceeds  received
          by Borrower  during such fiscal quarter as a result of the issuance of
          its capital stock.  "Tangible Capital Base" means total  shareholders'
          equity  plus  Subordinated   Debt,  less  intangible  assets,  all  as
          determined in accordance with generally accepted accounting principles
          from Borrower's



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<PAGE>



          financial  statements  delivered  to the BANK in  accordance  with the
          covenants  of the  Borrower  in the  Loan  Agreement  (the  "Financial
          Statements"); and

          D. Paragraph 2. of Section VII. Q. entitled "Additional  Financial and
     Other  Covenants"  shall be and hereby is replaced in its entirety with the
     following:

          "2. Borrower shall have "Debt  Coverage" (as  hereinafter  defined) of
          not less than 2:1 for each fiscal quarter  commencing October 4, 1998.
          For  purposes  hereof,   "Debt  Coverage"  shall  mean  the  ratio  of
          Borrower's net income for the applicable  fiscal quarter ending on the
          date of  determination,  before reduction for interest,  depreciation,
          taxes, and amortization expense for such period, but after the payment
          of  dividends  or  distributions  during such period to the  aggregate
          amount of interest expense on all indebtedness and current  maturities
          on long term debt payable by Borrower during such fiscal quarter,  all
          as  determined  in  accordance  with  generally  accepted   accounting
          principles from the Financial Statements; and"

          E. The following  representation  and warranty by Borrower is added as
     Section VI. P. of the Loan Agreement:

          "P. Year 2000 Representation.  Borrower represents and warrants to the
          BANK (which representation shall survive the making of the Loans) that
          the Borrower has taken all  necessary  action to assess,  evaluate and
          correct all of the hardware,  software,  embedded microchips and other
          processing  capabilities  it uses,  directly or indirectly,  to ensure
          that it will be able to function  accurately and without  interruption
          or ambiguity using date information  before,  during and after January
          1, 2000."


          2.   AMENDMENT OF OTHER LOAN DOCUMENTS.

          Each  of  the  other  Loan  Documents,  whether  or  not  specifically
     referenced herein,  shall be and hereby is amended to reflect the terms and
     conditions of this  amendment and to include  within the scope of such Loan
     Documents  and  the  description  of  Loans  and  Notes  therein,  and  the
     obligations  secured  thereby,  the  Revolving  Line  of  Credit  Loan  and
     Revolving Line of Credit Note as modified and renewed this date.



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<PAGE>



          3. REAFFIRMATION OF REPRESENTATIONS AND WARRANTIES.

          Borrower  hereby  confirms,   reasserts,   and  restates  all  of  the
     representations  and  warranties  under  the  Loan  Agreement  and the Loan
     Documents,  as amended  hereby,  as of the date hereof,  including  without
     limitation,  the  representations and warranties set forth in Article VI of
     the Loan Agreement.


          4. REAFFIRMATION OF AFFIRMATIVE COVENANTS.

          Borrower  hereby  confirms,  reasserts,  and restates its  Affirmative
     Covenants  as set forth in Article VII of the Loan  Agreement  and the Loan
     Documents, as amended hereby, as of the date hereof.


          5. REAFFIRMATION OF NEGATIVE COVENANTS.

          Borrower  hereby  confirms,   reasserts,  and  restates  its  Negative
     Covenants as set forth in Article VIII of the Loan  Agreement  and the Loan
     Documents, as amended hereby, as of the date hereof.


          6. FURTHER REPRESENTATION AND WARRANTIES.

          The Borrower represents and warrants to the Bank as follows:

               (a) The execution, delivery and performance of this Agreement and
          the documents  relating hereto (the "Amendment  Documents") are within
          the power of the Borrower and are not in contravention of any law, the
          Borrower's  Articles  of  Incorporation,  By-laws  or the terms of any
          other documents,  agreements or undertaking to which the Borrower is a
          party or by which the  Borrower  is bound.  No approval of any person,
          corporation,  governmental  body or other entity not provided herewith
          is  required  as  a  prerequisite  to  the  execution,   delivery  and
          performance  by  Borrower  of the  Amendment  Documents  or any of the
          documents  submitted  to the Bank in  connection  with  the  Amendment
          Documents to ensure the validity or enforceability thereof.

               (b) All necessary corporate action has been taken by the Borrower
          to authorize the execution,  delivery and performance of the Amendment
          Documents  which,  when  executed  on  behalf  of the  Borrower,  will
          constitute   the  legally   binding   obligations   of  the  Borrower,
          enforceable in accordance with their respective terms.



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<PAGE>



          7. REAFFIRMATION OF GUARANTY.

               The  Guarantor  hereby  confirms,  reasserts,  and  restates  its
          Guaranty,  as amended hereby, as of the date hereof; and the Guarantor
          acknowledges and agrees that the term "Guaranteed Obligations" therein
          shall include the Revolving Line of Credit Loan and the Revolving Line
          of Credit Note as modified and renewed this date.


          8. NO FURTHER EFFECT.

               Except as amended  hereby,  the terms and  conditions of the Loan
          Agreement  and each of the Loan  Documents as set forth  therein shall
          remain unchanged and, as hereby amended, are in full force and effect.







                           [Intentionally left blank.]



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<PAGE>



     IN WITNESS WHEREOF, the Borrower,  the Guarantor and the Bank have executed
and delivered  this  Amendment to the Loan  Agreement and Related Loan Documents
all as of the day and year first above written.


WITNESS:                                  BANK:
                                          CITIZENS BANK NEW HAMPSHIRE



/s/ Diane L. Bourque                     By: /s/ Dianne M. Srebnick
--------------------------                   -----------------------------------
                                             Dianne M. Srebnick, Vice President


                                          BORROWER:
                                          PRESSTEK, INC.



/s/ Diane L. Bourque                     By: /s/ Richard A. Williams
--------------------------                   -----------------------------------
                                             Name:  Richard A. Williams
                                             Title: Chief Executive Officer


                                          GUARANTOR:
                                          DELTA V TECHNOLOGIES, INC.


 /s/ Diane L. Bourque                    By: /s/ Richard A. Williams
--------------------------                   -----------------------------------
                                             Name:  Richard A. Williams
                                             Title: Director



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