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                                                                   EXHIBIT 4.12

                             SUPPLEMENTAL INDENTURE

                  SUPPLEMENTAL INDENTURE (this "Supplemental Indenture"), dated
as of September 24, 1998, among Data Documents Incorporated, a Delaware
corporation, Data Documents, Inc., a Nebraska corporation, and Moore Labels,
Inc., a Kansas corporation (each a "Guaranteeing Subsidiary" and, collectively,
the "Guaranteeing Subsidiaries"), each a direct or indirect wholly owned
subsidiary of CEX Holdings, Inc., a Delaware corporation (the "Company"), and
The Bank of New York, a New York banking corporation, as trustee, under the
Indenture referred to below (the "Trustee").

W I T N E S S E T H

                  WHEREAS, the Company, as Issuer, and certain of its other
subsidiaries, as Guarantors, have heretofore executed and delivered to the
Trustee an indenture (the "Indenture"), dated as of May 29, 1998 providing for
the issuance of an aggregate principal amount of up to $550,000,000 of 9-5/8%
Senior Subordinated Notes due 2008 (the "Notes");

                  WHEREAS, the Section 4.15 of the Indenture provides that
within 120 days of the Issue Date the Guaranteeing Subsidiaries shall execute
and deliver to the Trustee a supplemental indenture pursuant to which the
Guaranteeing Subsidiaries shall guaranty irrevocably and unconditionally all
principal, premium, if any, and interest (and Liquidated Damages, if any) on the
Notes, on a senior subordinated basis; and

                  WHEREAS, the Guaranteeing Subsidiaries desire to provide the
aforementioned guaranty in accordance with the terms set forth in Article 11 of
the Indenture (the "Guarantee"); and

                  WHEREAS, pursuant to Section 9.01 of the Indenture, the
Trustee is authorized to execute and deliver this Supplemental Indenture.

                  NOW THEREFORE, in consideration of the foregoing and for other
good and valuable consideration, the receipt of which is hereby acknowledged,
the Guaranteeing Subsidiaries and the Trustee mutually covenant and agree for
the equal and ratable benefit of the Holders of the Notes as follows:

                  1. CAPITALIZED TERMS. Capitalized terms used herein without
definition shall have the meanings assigned to them in the Indenture.

                  2. AGREEMENT TO GUARANTEE. Each Guaranteeing Subsidiary hereby
agrees to jointly and severally, along with all Guarantors named in the
Indenture, irrevocably and unconditionally guarantee (i) the due and punctual
payment of the principal of, premium, if any and interest (and Liquidated
Damages, if any) on the Notes, whether at stated maturity, by acceleration or
otherwise, the due and punctual payment of interest on the overdue principal,
and premium, if any, and to the extent permitted by law) interest on any
interest, if any, on the Notes and the due and punctual performance of all other
obligations of the Company, to the Holders or the Trustee, all in accordance
with the terms set forth in Article 11 of the Indenture, (ii) in the case of any
extension of time of payment or renewal of any Notes or such other obligations,
that the same will be promptly paid in full when due or performed in accordance
with the terms of the 





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extension or renewal, whether at stated maturity, by acceleration or otherwise,
and (iii) the payment of any and all costs and expenses (including reasonable
attorneys' fees) incurred by the Trustee or any Holder in enforcing any rights
under this Guarantee.

                  The obligations of each Guaranteeing Subsidiary to the Holders
and to the Trustee pursuant to this Supplemental Indenture are expressly set
forth in Article 11 of the Indenture and reference is hereby made to such
Indenture for the precise terms of this Guarantee.

                  THE TERMS OF ARTICLE 11 OF THE INDENTURE ARE INCORPORATED 
HEREIN BY REFERENCE.

                  3. NEW YORK LAW TO GOVERN. THE INTERNAL LAW OF THE STATE OF
NEW YORK SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE.

                  4. COUNTERPARTS. The parties may sign any number of copies of
this Supplemental Indenture. Each signed copy shall be an original, but all of
them together represent the same agreement.

                  5. EFFECT OF HEADINGS. The Section headings herein are for
convenience only and shall not affect the construction hereof.

                  6. THE TRUSTEE. The Trustee shall not be responsible in any
manner whatsoever for or in respect of the validity or sufficiency of this
Supplemental Indenture or for or in respect of the recitals contained herein,
all of which recitals are made solely by the Guaranteeing Subsidiaries.


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                  IN WITNESS WHEREOF, the parties hereto have caused this
Supplemental Indenture to be duly executed and attested, all as of the date
first above written.

                                       DATA DOCUMENTS INCORPORATED
                                       DATA DOCUMENTS, INC.
                                       MOORE LABELS, INC.


                                       By: /s/ John T. Skinner
                                          ---------------------------------
                                       Name:  John T. Skinner
                                       Title:  Vice President



                                       THE BANK OF NEW YORK,
                                         as Trustee





                                       By: /s/ Remo J. Reale
                                          ---------------------------------
                                           Authorized Signatory

Acknowledged and Agreed:

CEX HOLDINGS, INC.



By:  /s/ Gary M. Jacobs
   ------------------------------
         Gary M. Jacobs
         Executive Vice President



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