EXHIBIT 10 (d) ADDENDUM NO. 13 REVOLVING LOAN AND SECURITY AGREEMENT CONVERTIBLE REVOLVING CREDIT PROMISSORY NOTE DATED OCTOBER 26, 1987 For consideration given and received, Robert Howard and Howtek, Inc. hereby agree to extend the repayment date in Paragraph D of the above referenced Convertible Revolving Credit Promissory Note, as amended, (the "Note") from January 4, 2002 to January 4, 2003. Also the Note hereafter will be a maximum principal sum of Three Million Dollars ($3,000,000). Effective the 29th day of December 2001. HOWTEK, INC. By: /s/ Annette Heroux /s/ Robert Howard -------------------------- ------------------- Title: Chief Financial Officer Robert Howard