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                                IMAX CORPORATION

                                  EXHIBIT 4.10

                          FOURTH SUPPLEMENTAL INDENTURE

          Fourth Supplemental Indenture (this "Fourth Supplemental Indenture"),
dated as of April 10, 2006 among IMAX Corporation, a corporation incorporated
under the federal laws of Canada (the "Company"), the Guarantors named in the
Indenture referred to below (the "Existing Guarantors"), the First Supplemental
Guarantors named in the Supplemental Indenture referred to below, the Second
Supplemental Guarantor named in the Second Supplemental Indenture referred to
below, Conversion Films Ltd., Feathered Films Ltd. and Great Ant Productions
Ltd. (each a "Guaranteeing Subsidiary") and U.S. Bank National Association, as
trustee under the Indenture referred to below (the "Trustee").

                                   WITNESSETH

          WHEREAS, the Company and the Existing Guarantors have heretofore
executed and delivered to the Trustee an indenture (the "Indenture"), dated as
of December 4, 2003, as amended by the First Supplemental Indenture dated as of
April 1, 2004 among the Company, the Existing Guarantors, 3D Sea II Ltd. and
Taurus-Littrow Productions Inc. (the "First Supplemental Guarantors") and the
Trustee (the "First Supplemental Indenture"), as further amended by the Second
Supplemental Indenture dated as of July 14, 2004 among the Company, the Existing
Guarantors, the First Supplemental Guarantors and Big Engine Films Inc. (the
"Second Supplemental Guarantor") and the Trustee (the "Second Supplemental
Indenture"), and as further amended by the Third Supplemental Indenture dated as
of February 2, 2005 among the Company, the Existing Guarantors, the First
Supplemental Guarantors, the Second Supplemental Guarantor and Automation
Productions Ltd. (the "Third Supplemental Guarantor") and the Trustee (the
"Third Supplemental Indenture"), providing for the issuance of 9 5/8% Senior
Notes due 2010 (the "Securities");

          WHEREAS, IMAX Sanddle Animation, one of the Existing Guarantors, was
dissolved on February 8, 2005, and the Third Supplemental Guarantor was
dissolved on December 31, 2005 and each are therefore no longer Guarantors.

          WHEREAS, the Indenture provides that under certain circumstances each
Guaranteeing Subsidiary shall execute and deliver to the Trustee a supplemental
indenture pursuant to which any newly-acquired or created Guarantor shall
unconditionally guarantee all of the Company's obligations under the Securities
and the Indenture on the terms and conditions set forth herein (the "Subsidiary
Guarantee"); and

          WHEREAS, pursuant to Section 901 of the Indenture, the Trustee is
authorized to execute and deliver this Fourth 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 Subsidiary and the Trustee mutually covenant and agree for the
equal and ratable benefit of the Holders of the Securities as follows:

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

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          2. Agreement to Guarantee. Each Guaranteeing Subsidiary irrevocably
and unconditionally guarantees the Guarantee Obligations, which include (i) the
due and punctual payment of the principal of, premium, if any, and interest and
Special Interest, if any, on the Securities, whether at maturity, by
acceleration, redemption, upon a Change of Control Offer, upon an Asset Sale
Offer 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 on the Securities, and payment of expenses, 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 XIII of the
Indenture, and (ii) in case of any extension of time of payment or renewal of
any Securities or any such other obligations, that the same will be promptly
paid in full when due or performed in accordance with the terms of the extension
or renewal, whether at stated maturity, by acceleration, redemption, upon a
Change of Control Offer, upon an Asset Sale Offer or otherwise.

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

          No past, present or future director, officer, partner, manager,
employee, incorporator or stockholder (direct or indirect) of either of the
Guaranteeing Subsidiaries (or any such successor entity), as such, shall have
any liability for any obligations of such Guaranteeing Subsidiary under this
Subsidiary Guarantee or the Indenture or for any claim based on, in respect of,
or by reason of, such obligations or their creation, except in their capacity as
an obligor or Guarantor of the Securities in accordance with the Indenture.

          This is a continuing Guarantee and shall remain in full force and
effect and shall be binding upon each Guaranteeing Subsidiary and its successors
and assigns until full and final payment of all of the Company's obligations
under the Securities and Indenture or until released in accordance with the
Indenture and shall inure to the benefit of the successors and assigns of the
Trustee and the Holders, and, in the event of any transfer or assignment of
rights by any Holder or the Trustee, the rights and privileges herein conferred
upon that party shall automatically extend to and be vested in such transferee
or assignee, all subject to the terms and conditions hereof. This is a Guarantee
of payment and not of collectibility.

          The obligations of each Guaranteeing Subsidiary under its Subsidiary
Guarantee shall be limited to the extent necessary to insure that it does not
constitute a fraudulent conveyance under applicable law.

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

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

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


                                        2

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          5. Effect of Headings. The Section headings herein are for convenience
only and shall not affect the construction hereof.


                                        3

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


                                       IMAX Corporation


                                       By "G. Mary Ruby"
                                          -------------------------------------
                                       Name: G. Mary Ruby
                                       Title: Sr. Vice President, Legal Affairs,
                                              Deputy General Counsel and
                                              Corporate Secretary


                                       By "Edward MacNeil"
                                          -------------------------------------
                                       Name: Edward MacNeil
                                       Title: Vice President Finance, Tax and
                                              Special Projects


                                       EXISTING GUARANTORS:

                                       David Keighley Productions 70MM Inc.
                                       IMAX II U.S.A. Inc.
                                       IMAX Chicago Theatre LLC
                                          By its Managing Member
                                          IMAX Theatre Holding
                                          (California I) Co.
                                       IMAX Minnesota Holding Co.
                                       IMAX Rhode Island Limited Partnership
                                          By its General Partner
                                          IMAX Providence General Partner Co.
                                       IMAX Scribe Inc.
                                       IMAX Space Ltd.
                                       IMAX Theatre Holding Co.
                                       IMAX Theatre Holdings (OEI) Inc.
                                       IMAX Theatre Management Company
                                       IMAX Theatre Services Ltd.
                                       IMAX U.S.A. Inc.
                                       Miami Theatre LLC
                                          By its Managing Member
                                          IMAX Theatre Holding
                                          (California I) Co.
                                       Nyack Theatre LLC
                                          By its Managing Member
                                          IMAX Theatre Holding (Nyack I) Co.
                                       Parker Pictures Ltd.
                                       Ridefilm Corporation
                                       Sacramento Theatre LLC
                                          By its Managing Member
                                          IMAX Theatre Holding
                                          (California I) Co.

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                                        Sonics Associates, Inc.
                                        Starboard Theatres Ltd.
                                        Tantus Films Ltd.
                                        1329507 Ontario Inc.
                                        924689 Ontario Inc.
                                        IMAX (Titanica) Ltd.
                                        IMAX (Titanic) Inc.
                                        IMAX Music Ltd.
                                        IMAX Film Holding Co.
                                        IMAX Indianapolis LLC
                                        IMAX Providence General Partner Co.
                                        IMAX Providence Limited Partner Co.
                                        IMAX Theatre Holding (California I) Co.
                                        IMAX Theatre Holding (California II) Co.
                                        IMAX Theatre Holding (Nyack I) Co.
                                        IMAX Theatre Holding (Nyack II) Co.
                                        IMAX Theatre Management
                                        (Scottsdale), Inc.
                                        Strategic Sponsorship Corporation
                                        Tantus II Films Ltd.
                                        RPM Pictures Ltd.


                                        By "G. Mary Ruby"
                                           -------------------------------------
                                        Name: G. Mary Ruby
                                        Title: Secretary


                                        By "Edward MacNeil"
                                           -------------------------------------
                                        Name: Edward MacNeil
                                        Title: Vice President


                                        FIRST SUPPLEMENTAL GUARANTORS:

                                        Taurus-Littrow Productions Inc.
                                        3D Sea II Ltd.


                                        By "G. Mary Ruby"
                                           -------------------------------------
                                        Name: G. Mary Ruby
                                        Title: Secretary


                                        By "Edward MacNeil"
                                           -------------------------------------
                                        Name: Edward MacNeil
                                        Title: Vice President

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                                        SECOND SUPPLEMENTAL GUARANTOR:

                                        Big Engine Films Inc.


                                        By "G. Mary Ruby"
                                           -------------------------------------
                                        Name: G. Mary Ruby
                                        Title: Secretary


                                        By "Edward MacNeil"
                                           -------------------------------------
                                        Name: Edward MacNeil
                                        Title: Vice President


                                        GUARANTEEING SUBSIDIARIES:

                                        Conversion Films Ltd.
                                        Feathered Films Ltd.
                                        Great Ant Productions Ltd.


                                        By "G. Mary Ruby"
                                           -------------------------------------
                                        Name: G. Mary Ruby
                                        Title: Secretary


                                        By "Edward MacNeil"
                                           -------------------------------------
                                        Name: Edward MacNeil
                                        Title: Vice President

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                                        TRUSTEE:

                                        U.S. Bank National Association,
                                           As Trustee


                                        By:"Raymond S. Haverstock"
                                           -------------------------------------
                                        Name: Raymond S. Haverstock
                                        Title: Vice President