**Exhibit 10.15****Addendum #1 to Patent License Agreement**This Addendum to Patent License Agreement is between Nocopi Technologies, Inc. (Licensor) and GiddyUp, LLC and Color Loco, LLC (jointly and severally, Licensee)1. BackgroundLicensor and Licensee are parties to a Patent License Agreement (the Agreement) effective April 1,2006. All capitalized words appearing in this Addendum shall have the same definitions set forthin the Agreement. The parties intend, by this Addendum, to expand the scope of the License toinclude Activating Markers. Except as expressly modified by this Addendum, the License to use thePatented Ink Technology with Activating Markers shall be governed by the terms and conditions ofthe Agreement.2. Expanded License GrantThe License is hereby expanded to include Activating Markers. “Activating Markers” are defined aschildren’s merchandise such as soft cover books, activity/art kits, stationery, stickers, andsticker books, whether or not the suggested retail price is in excess of or below $2.50 per item,utilizing Licensor’s Patented Ink Technology that is activated solely by use of a Activatingmarker, pen or other device, and not by scratching or rubbing. If an item of merchandise includesan Activating Marker but is also marketed to permit or enable the Patented Ink Technology to beactivated by scratching or rubbing, it shall be considered a Product or Other Product under theAgreement, and not an Activating Marker under this Addendum.3. Annual Royalties Based on Shipments of Activating MarkersSeparate and apart from the Annual Royalties and Quarterly Royalties set forth in the Agreement,Licensee shall pay Licensor an Annual Royalty and Quarterly Royalty, in the manner set forth in theAgreement, with respect to all Activating Markers that are billed and shipped. The royalty rateapplicable to Activating Markers shall always be three percent (3%), payable as set forth in theAgreement. With each Quarterly Royalty relating to shipments of Activating Markers, Licensee shallprovide Licensor with a Report containing the information required by the Agreement and sufficientto enable Licensor to differentiate sales of Activating Markers from Licensee’s sales of Productsor Other Products. The 3% royalty rate applicable to shipments of Activating Markers shall not bemodified or reduced whether or not the merchandise contains licensed marks of third parties (e.g.,Disney, Sesame Street, etc.), or whether or not the customers purchasing the Activating Markerswould otherwise qualify as Special Rate Customers.4. No Minimum Annual Royalties Based on Shipments of Activating MarkersLicensee shall actively promote the sale of Activating Markers during the Term of the Agreement;provided, however, that anything in the Agreement to the contrary notwithstanding, (a) Licenseeshall have no minimum royalty obligations during the
 

 
Development Period or any Annual Periodthereafter with respect to Activating Markers, and (b) sales of Activating Markers shall not becount towards or be applied as a credit against any minimum royalties, Annual Royalties orQuarterly Royalties otherwise required in the Agreement.5. Licensor’s Sales of Ink to Licensee’s Approved PrintersUpon the commencement date of this Addendum, Licensee shall use its best commercial efforts tocause its Approved Printers to purchase Ink for use with its Activating Markers from Licensor.Commencing on June 1, 2007, Licensee shall cause its Approved Printers exclusively to purchase Inkfor use with its Activating Markers from Licensor and shall exclusively use such Ink with itsActivating Markers. Licensor shall sell its Ink for use with the Activating Markers to Licensee’sApproved Printers as contemplated by the Agreement.6. Term of AddendumThis Addendum shall commence on August 1, 2006, and, unless sooner terminated, shall remain ineffect during the Term of the Agreement. This Addendum and the rights and obligations set forthherein shall terminate automatically upon termination or expiration of the Agreement for anyreason. In addition, if either Party breaches any of its obligations under this Addendum and failsto cure such breach to the reasonable satisfaction of the non-breaching Party within ten (10)calendar days after written notice from the non-breaching Party if the breach relates to thenon-payment of money, or within thirty (30) calendar days after such written notice for any othertype of breach, the non-breaching Party, at its election may affirm this Addendum and seek andsecure specific performance by the breaching Party of its obligations under this Addendum or mayterminate this Addendum (without terminating the Agreement unless such breach also constitutes abreach of the Agreement) and, in either instance, may seek and secure reimbursement for damagesincurred as a result of such breach.**In witness whereof**, the Parties execute this Addendum as of the commencement date set forth above,intending to be legally bound.     **Nocopi Technologies, Inc.** **Giddy Up, LLC**        Title:  Title:       **Color Loco, LLC**          Title:    
2