ANNEX A
                                                                         -------
                            to Subsidiaries Guaranty


                      SUPPLEMENT TO SUBSIDIARIES GUARANTEE

                  SUPPLEMENT,    dated   as   of                           (this
"Supplement"),   made   by                             ,   a                    
corporation (the "Additional Guarantor"),  in favor of CANADIAN IMPERIAL BANK OF
COMMERCE as administrative agent (in such capacity, the "Administrative  Agent")
for the Lenders (the "Lenders") and Canadian Imperial Bank Of Commerce as issuer
of the Letters of Credit (as defined in the Credit Agreement  referenced  below)
(in such  capacity,  the  "Issuing  Lender")  parties  to the  Credit  Agreement
referred  to below.  All  capitalized  terms not defined  herein  shall have the
meaning ascribed to them in the Credit Agreement.

                                    RECITALS

         WHEREAS,  reference  is hereby made to that certain  Credit  Agreement,
dated  as of March    ,  1998,  among  Unidigital  Inc.  (the  "Borrower"),  the
Administrative   Agent,   the  Lenders  and  the  Issuing  Lender  (as  amended,
supplemented  or  otherwise   modified  as  of  the  date  hereof,  the  "Credit
Agreement");

         WHEREAS,  in connection with the Credit Agreement,  the Subsidiaries of
the  Borrower   (other  then  the  Additional   Guarantor)   (collectively   the
"Guarantors"  and  each  a  "Guarantor")  have  entered  into  the  Subsidiaries
Guarantee,  dated as of March   , 1998, in favor of the Administrative Agent for
the ratable benefit of Lenders and the Issuing Lender (as amended,  supplemented
or otherwise modified as of the date hereof, the "Subsidiaries Guarantee");

         WHEREAS,  Section 9.9 of the Credit Agreement  requires that should the
Borrower  at any time  acquire or form any  Subsidiary,  such  Subsidiary  shall
become  party  to the  Subsidiaries  Guarantee  and  the  Subsidiaries  Security
Agreement;

         WHEREAS,  the  Additional  Guarantor  has agreed to execute and deliver
this Supplement in order to become a party to the Subsidiaries Guarantee.

         NOW, THEREFORE, IT IS AGREED:

         1. Subsidiaries Guarantee. By executing and delivering this Supplement,
the  Additional  Guarantor,  as  provided  in  Section  26 of  the  Subsidiaries
Guarantee,  hereby becomes a party to the Subsidiaries  Guarantee as a Guarantor
thereunder  with the same force and effect as if  originally  named therein as a
Guarantor  and,  without  limiting  the  generality  of  the  foregoing,  hereby
expressly assumes all obligations and liabilities of a Guarantor thereunder. The
Additional   Guarantor   hereby   represents   and  warrants  the  each  of  the
representations  and  warranties  contained  in Section     of the  Subsidiaries
Guarantee is true and


                                     - 13 -


correct on and as of the date hereof (after giving effect to this Supplement) as
if made on and as of such date.

         2. Governing Law. THIS  SUPPLEMENT  SHALL BE GOVERNED BY, AND CONSTRUED
AND INTERPRETED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

                  IN WITNESS WHEREOF, the undersigned has caused this Supplement
to be duly executed and delivered as of the date first above written.

                                        [NAME OF ADDITIONAL GUARANTOR],
                                        a                      corporation
                                          --------------------

                                        By:
                                           -------------------------------------
                                           Name:
                                           Title: