<PAGE>   1
                                  EXHIBIT 10.4

                           ACCENT COLOR SCIENCES, INC.

                          REGISTRATION RIGHTS AGREEMENT


           This Registration Rights Agreement ("Agreement"), dated as of
September 7, 1999, is between Accent Color Sciences, Inc., a Connecticut
corporation (the "Company"), and each investor set forth on Schedule A hereto
(individually an "Investor" and collectively with all other Investors, the
"Investors").

                                   BACKGROUND

           Pursuant to that certain Series A Convertible Subordinated Note,
Common Stock and Warrant Purchase Agreement, dated the date hereof, between the
Company and the Investors (the "Purchase Agreement"), the Company has conducted
a bridge financing in which it has offered for sale Series A Convertible
Subordinated Notes (the "Notes"), shares of Common Stock (the "Bridge Shares")
and Warrants (the "Warrants") to purchase the Company's common stock. In order
to induce the Investors to purchase the Notes, the Bridge Shares and the
Warrants, the Company has agreed to provide the registration rights set forth in
this Agreement.

                                    AGREEMENT

           Now, therefore, in consideration of the various covenants and
agreements contained herein and in the Purchase Agreement, and intending to be
legally bound hereby, the Company agrees with the Investors as follows:

           1.        REGISTRATION RIGHTS.

                  1.1 CERTAIN DEFINITIONS. Capitalized terms used but not
defined herein shall have the meanings ascribed to such terms in the Purchase
Agreement. As used in this Agreement, the following terms shall have the
following respective meanings:

                           (a) "Commission" shall mean the Securities and
Exchange Commission or any other federal agency at the time administering the
Securities Act.

                           (b) "Common Stock" shall mean the common stock, no
par value, of the Company.

                           (c) "Exchange Act" shall mean the Securities Exchange
Act of 1934, as amended.

                           (d) "Investors" shall have the meaning assigned in
the preamble to this Agreement and shall include each assignee or successor to
each Investor.
<PAGE>   2
                  (e) The terms "Register", "Registered" and "Registration"
         refer to a registration effected by preparing and filing a Registration
         Statement in compliance with the Securities Act, and the declaration or
         ordering of the effectiveness of such Registration Statement by the
         Commission.

                  (f) "Registrable Securities" shall mean the Shares so long as
         such shares are ineligible for sale under subparagraph (k) of Rule 144.

                  (g) "Registration Expenses" shall mean all expenses incurred
         by the Company in complying with Section 1 hereof, including, without
         limitation, all federal and state registration, qualification and
         filing fees, Nasdaq or exchange listing fees, printing expenses, fees
         and disbursements of counsel for the Company, blue sky fees and
         expenses, the expense of any special audits incident to or required by
         any such Registration and the reasonable fees and disbursements of
         counsel for the Selling Shareholders, as selling shareholders.

                  (h) "Registration Statement" shall mean Form S-1, Form SB-1,
         Form S-2, Form SB-2 or Form S-3, promulgated by the Commission (or any
         successor forms) whichever is applicable.

                  (i) "Restriction Termination Date" shall mean, with respect to
         any Registrable Securities, the earliest of (i) the date that such
         Registrable Securities shall have been Registered and sold or otherwise
         disposed of in accordance with the intended method of distribution by
         the seller or sellers thereof set forth in the Registration Statement
         covering such securities or transferred in compliance with Rule 144,
         and (ii) the date that an opinion of counsel to the Company containing
         reasonable assumptions (which opinion shall be subject to the
         reasonable approval of counsel to any affected Investor) shall have
         been rendered to the effect that the legend referred to in Section
         3.8(a) of the Subscription Agreement can be properly removed as
         inapplicable because the Registrable Securities covered thereby can be
         freely traded and such legend shall have been removed.

                  (j) "Rule 144" shall mean Rule 144 promulgated by the
         Commission pursuant to the Securities Act.

                  (k) "Securities Act" shall mean the Securities Act of 1933, as
         amended.

                  (l) "Selling Expenses" shall mean all underwriting discounts
         and selling commissions applicable to the sale of Registrable
         Securities pursuant to this Agreement.

                  (m) "Selling Shareholders" shall mean the holder or holders of
         Registrable Securities who requests Registration under Section 1
         herein.

                  (n) "Shares" shall mean the Bridge Shares and the Common Stock
         issued to the Investors upon conversion of the Notes and upon exercise
         of the Warrants.



                                      -2-
<PAGE>   3
                  (p) "Other Registrable Securities" shall mean (i) the Common
Stock issued to holders of the Company's Series B Preferred Stock upon
conversion of such stock and with respect to which such holders have been
granted registration rights pursuant to the Registration Rights Agreement
between the Company and such holders, and (ii) the Common Stock held by common
shareholders of the Company and with respect to which such shareholders have
been granted registration rights pursuant to the Registration Rights Agreement
between the Company and such shareholders.

         1.2 REQUIRED REGISTRATION. If the Company shall be requested by holders
of at least a majority of the outstanding Shares to effect the Registration of
Registrable Securities, then the Company shall promptly give written notice of
such proposed Registration to all holders of Shares, and thereupon the Company
shall promptly use its best efforts to effect the Registration of the
Registrable Securities that the Company has been requested to Register for
disposition as described in the request of such holders of Shares and in any
response received from any of the holders of Shares within ten (10) days or such
longer period as shall be set forth in the notice, after the giving of the
written notice by the Company; provided, however, that the Company shall not be
obligated to effect any Registration except in accordance with the following
provisions:

                  (a) The Company shall not be obligated to file and cause to
become effective more than one (1) Registration Statement in which Registrable
Securities are Registered pursuant to this Section 1.2.

                  (b) Notwithstanding the foregoing, the Company may include in
each such Registration requested pursuant to this Section 1.2 any authorized but
unissued shares of Common Stock (or treasury shares) for sale by the Company or
any issued and outstanding shares of Common Stock for sale by others; provided,
however, that, if the number of shares of Common Stock so included pursuant to
this clause (b) exceeds the number of Registrable Securities requested by the
holders of Shares requesting such Registration, then such Registration shall be
deemed to be a Registration in accordance with and pursuant to Section 1.3 of
this Agreement (and not this Section 1.2); and provided further, however, that
the inclusion of such authorized but unissued shares of Common Stock (or
treasury shares) by the Company or issued and outstanding shares of Common Stock
by others in such Registration shall not prevent the holders of Shares
requesting such Registration from registering the entire number of Registrable
Securities requested by them.

                  (c) The Company shall not be required to file a registration
statement pursuant to this Section 1.2: (i) within six (6) months after any
other registration by the Company or (ii) for six (6) months after the request
for Registration under this Section 1.2 if the Company is then engaged in
negotiations regarding a material transaction which has not otherwise been
publicly disclosed, or such shorter period ending on the date, whichever first
occurs, that such transaction is publicly disclosed, abandoned or consummated.

         1.3 PIGGYBACK REGISTRATION.




                                      -3-
<PAGE>   4
                  (a) Each time that the Company proposes to Register a public
offering solely of its Common Stock (not including an offering of Common stock
issuable upon conversion or exercise of other securities), other than pursuant
to a Registration Statement on Form S-4 or Form S-8 or similar or successor
forms (collectively, "Excluded Forms"), the Company shall promptly give written
notice of such proposed Registration to all holders of Shares, which shall offer
such holders the right to request inclusion of any Registrable Securities in the
proposed Registration.

                  (b) Each holder of Shares shall have ten (10) days or such
longer period as shall be set forth in the notice from the receipt of such
notice to deliver to the Company a written request specifying the number of
shares of Registrable Securities such holder intends to sell and the holder's
intended plan of disposition.

                  (c) In the event that the proposed Registration by the Company
is, in whole or in part, an underwritten public offering of securities of the
Company, any request under Section 1.3(b) may specify that the Registrable
Securities be included in the underwriting on the same terms and conditions as
the shares of Common Stock, if any, otherwise being sold through underwriters
under such Registration.

                  (d) Upon receipt of a written request pursuant to Section
1.3(b), the Company shall promptly use its best efforts to cause all such
Registrable Securities to be Registered, to the extent required to permit sale
or disposition as set forth in the written request.

                  (e) Notwithstanding the foregoing, if the managing underwriter
of an underwritten public offering determines and advises in writing that the
inclusion of all Registrable Securities proposed to be included in the
underwritten public offering, together with any other issued and outstanding
shares of Common Stock proposed to be included therein by holders other than the
holders of Registrable Securities (such other shares hereinafter collectively
referred to as the "Other Shares"), would interfere with the successful
marketing of the securities proposed to be included in the underwritten public
offering, then the number of such shares to be included in such underwritten
public offering shall be reduced, and shares shall be excluded from such
underwritten public offering in a number deemed necessary by such managing
underwriter, to the extent necessary, pro rata with respect to the Registrable
Securities sought to be included therein and all Other Shares otherwise entitled
to be included therein.

                  (f) All Shares that are not included in the underwritten
public offering shall be withheld from the market by the holders thereof for a
period, not to exceed 6 months following a public offering, that the managing
underwriter reasonably determines as necessary in order to effect the
underwritten public offering. The holders of such Shares shall execute such
customary documentation as the managing underwriter reasonably requests to
evidence this lock-up.

         1.4 PREPARATION AND FILING. If and whenever the Company is under an
obligation pursuant to the provisions of this Section 1 to use its best efforts
to effect the Registration of any Registrable Securities, the Company shall, as
expeditiously as practicable:





                                      -4-
<PAGE>   5
                  (a) prepare and file with the Commission a Registration
Statement with respect to such Registrable Securities and use its best efforts
to cause such Registration Statement to become and remain effective in
accordance with Section 1.4(b) hereof, keeping each Selling Shareholder advised
as to the initiation, progress and completion of the Registration;

                  (b) prepare and file with the Commission such amendments and
supplements to such Registration Statements and the prospectus used in
connection therewith as may be necessary to keep such Registration Statement
effective for six months or, if sooner, until all Registrable Securities covered
by such Registration Statement have been sold, and to comply with the provisions
of the Securities Act with respect to the sale or other disposition of all
Registrable Securities covered by such registration statement;

                  (c) furnish to each Selling Shareholder such number of copies
of any summary prospectus or other prospectus, including a preliminary
prospectus, in conformity with the requirements of the Securities Act, and such
other documents as such Selling Shareholder may reasonably request in order to
facilitate the public sale or other disposition of such Registrable Securities;

                  (d) use its best efforts to register or qualify the
Registrable Securities covered by such registration statement under the
securities or blue sky laws of such jurisdictions as each Selling Shareholder
shall reasonably request and do any and all other acts or things which may be
necessary or advisable to enable such holder to consummate the public sale or
other disposition in such jurisdictions of such Registrable Securities;
provided, however, that the Company shall not be required to consent to general
service of process, qualify to do business as a foreign corporation where it
would not be otherwise required to qualify or submit to liability for state or
local taxes where it is not liable for such taxes; and

                  (e) at any time when a prospectus covered by such Registration
Statement is required to be delivered under the Securities Act within the
appropriate period mentioned in Section 1.3(b) hereof, notify each Selling
Shareholder of the happening of any event as a result of which the prospectus
included in such Registration, as then in effect, includes an untrue statement
of a material fact or omits to state a material fact required to be stated
therein or necessary to make the statements therein not misleading in the light
of the circumstances then existing and, at the request of such seller, prepare,
file and furnish to such seller a reasonable number of copies of a supplement to
or an amendment of such prospectus as may be necessary so that, as thereafter
delivered to the purchasers of such shares, such prospectus shall not include an
untrue statement of a material fact or omit to state a material fact required to
be stated therein or necessary to make the statement therein not misleading in
the light of the circumstances then existing.

         1.5 EXPENSES. The Company shall pay all Registration Expenses incurred
by the Company in complying with this Section 1; provided, however, that all
Selling Expenses applicable to the Registrable Securities covered by
registrations effected pursuant to Section 1 hereof shall be borne by the seller
or sellers thereof based on the number of Registrable Securities sold by such
seller or sellers.




                                      -5-
<PAGE>   6
         1.6 INFORMATION FURNISHED BY INVESTOR. It shall be a condition
precedent to the Company's obligations under this Agreement as to any Selling
Shareholder that such Selling Shareholder furnish to the Company in writing such
information regarding such Selling Shareholder and the distribution proposed by
such Selling Shareholder as is required by the Securities Act or otherwise by
the Commission.

         1.7 INDEMNIFICATION.

                  (a) Company's Indemnification of Investors. The Company shall
indemnify each Selling Shareholder, each of its officers, directors and
constituent partners, and each person controlling such Selling Shareholder, and
each underwriter thereof, if any, and each of its officers, directors,
constituent partners, and each person who controls such underwriter, against all
claims, losses, damages or liabilities (or actions in respect thereof) suffered
or incurred by any of them, to the extent such claims, losses, damages or
liabilities arise out of or are based upon any untrue statement (or alleged
untrue statement) of a material fact contained in any Registration Statement
covering the sale of Registrable Securities or any related prospectus, or any
omission (or alleged omission) to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading, or
any violation by the Company of any rule or regulation promulgated under the
Securities Act, the Exchange Act or any state blue sky laws applicable to the
Company and relating to actions or inaction required of the Company in
connection with any such Registration; and the Company will reimburse each such
Selling Shareholder, each such underwriter, each of their officers, directors
and constituent partners and each person who controls any such Selling
Shareholder or underwriter, for any legal and any other expenses as reasonably
incurred in connection with investigating or defending any such claim, loss,
damage, liability or action; provided, however, that the indemnity contained in
this Section 1.7(a) shall not apply to amounts paid in settlement of any such
claim, loss, damage, liability or action if settlement is effected without the
consent of the Company (which must not be unreasonably withheld); and provided,
however, that the Company will not be liable in any such case to the extent that
any such claim, loss, damage, liability or expense arises out of or is based
upon any untrue statement or omission based upon written information furnished
to the Company by such Selling Shareholder, underwriter, controlling person or
other indemnified person for use in connection with the offering of securities
of the Company.

                  (b) Selling Shareholder's Indemnification of Company. Each
Selling Shareholder (severally and not jointly) shall indemnify the Company,
each of its directors and officers, each underwriter, if any, of the Company's
Registrable Securities covered by a Registration Statement, each person who
controls the Company or such underwriter within the meaning of the Securities
Act, and each other Selling Shareholder, each of its officers, directors and
constituent partners and each person controlling such other Selling Shareholder,
against all claims, losses, damages and liabilities (or actions in respect
thereof) suffered or incurred by any of them and arising out of or based upon
any untrue statement (or alleged untrue statement) of a material fact contained
in such Registration Statement or related prospectus, or any omission (or
alleged omission) to state therein a material fact required to be stated therein
or necessary to make the statements therein not





                                      -6-
<PAGE>   7
misleading, which in either case arises from written information provided by the
Selling Shareholder for inclusion in such Registration Statement; and will
reimburse the Company, each other Selling Shareholders, such directors,
officers, partners, persons, underwriters and controlling persons for any legal
and any other expenses reasonably incurred in connection with investigating or
defending any such claim, loss, damage, liability or action.

                  (c) Indemnification Procedure. Promptly after receipt by an
indemnified party under this Section 1.7 of notice of the commencement of any
action which may give rise to a claim for indemnification hereunder, such
indemnified party will, if a claim in respect thereof is to be made against an
indemnifying party under this Section 1.7, notify the indemnifying party in
writing of the commencement thereof and generally summarize such action. The
indemnifying party shall have the right to participate in and to assume the
defense of such claim, and shall be entitled to select counsel for the defense
of such claim with the approval of any parties entitled to indemnification,
which approval shall not be unreasonably withheld. Notwithstanding the
foregoing, the parties entitled to indemnification shall have the right to
employ separate counsel (reasonably satisfactory to the indemnifying party) to
participate in the defense thereof, but the fees and expenses of such counsel
shall be at the expense of such indemnified parties unless the named parties to
such action or proceedings include both the indemnifying party and the
indemnified parties and the indemnifying party or such indemnified parties shall
have been advised by counsel that there are conflicting interests between the
indemnified parties and the indemnifying party (in which case, if the
indemnified parties notify the indemnifying party in writing that they elect to
employ separate counsel at the reasonable expense of the indemnifying party, the
indemnifying party shall not have the right to assume the defense of such action
or proceeding on behalf of the indemnified parties; it being understood,
however, that the indemnifying party shall not, in connection with any such
action or proceeding or separate or substantially similar or related action or
proceeding in the same jurisdiction arising out of the same general allegations
or circumstances, be liable for the reasonable fees and expenses of more than
one separate counsel at any time for all indemnified parties, which counsel
shall be designated in writing by the Investors of a majority of the Registrable
Securities).

                  (d) Contribution. If the indemnification provided for in this
Section 1.7 from an indemnifying party is unavailable to an indemnified party
hereunder in respect to any losses, claims, damages, liabilities or expenses
referred to herein, then the indemnifying party, in lieu of indemnifying such
indemnified party, shall contribute to the amount paid or payable by such
indemnified party as a result of such losses, claims, damages, liabilities or
expenses in such proportion as is appropriate to reflect the relative fault of
the indemnifying party and indemnified party in connection with the statements
or omissions which result in such losses, claims, damages, liabilities or
expenses, as well as any other relevant equitable considerations. The relative
fault of such indemnifying party and indemnified party shall be determined by
reference to, among other things, whether the untrue or alleged untrue statement
of a material fact or the omission or alleged omission to state a material fact
relates to information supplied by such indemnifying party or indemnified party
and the parties' relative intent, knowledge, access to information supplied by
such indemnifying party or indemnified party and opportunity to correct or
prevent such statement or omission. The amount paid or payable by a party as a
result of the losses, claims, damages, liabilities and expenses referred to
above shall be deemed to include any legal or other fees or expenses





                                      -7-
<PAGE>   8
reasonably incurred by such party in connection with investigating or defending
any action, suit, proceeding or claim.

         2. COVENANTS OF THE COMPANY. The Company agrees as follows:

                  (a) The Company will notify the holders of Registrable
Securities included in a Registration Statement of the issuance by the
Commission of any stop order suspending the effectiveness of such Registration
Statement or the initiation of any proceedings for that purpose. The Company
will make every reasonable effort to prevent the issuance of any stop order and,
if any stop order is issued, to obtain the lifting thereof at the earliest
possible time.

                  (b) If the Common Stock is then listed on a national
securities exchange, the Company will use its best efforts to cause the
Registrable Securities to be listed on such exchange. If the Common Stock is not
then listed on a national securities exchange, the Company will use its best
efforts to facilitate the reporting of the Registrable Securities on the Nasdaq
National Market.

                  (c) The Company will take all other reasonable actions
necessary to expedite and facilitate disposition of the Registrable Securities
by the holders thereof pursuant to the Registration Statement.

                  (d) With a view to making available to the holders of
Registrable Securities the benefits of Rule 144 promulgated under the Securities
Act and any other rule or regulation of the Commission that may at any time
permit the Investors to sell securities of the Company to the public without
registration, the Company agrees to:

                               (i) make and keep public information available,
           as those terms are understood and defined in Rule 144, at all times
           after 90 days after the effective date of the first Registration
           Statement filed by the Company for the offering of its securities to
           the general public;

                               (ii) file with the Commission in a timely manner
           all reports and other documents required of the Company under the
           Securities Act and the Exchange Act; and

                               (iii) furnish to each holder of Shares, so long
           as such holder of Shares owns any Shares, forthwith upon written
           request (a) a written statement by the Company that it has complied
           with the reporting requirements of Rule 144 (at any time after 90
           days after the effective date of the first registration statement
           filed by the Company), the Securities Act and the Exchange Act (at
           any time after it has become subject to such reporting requirements),
           (b) a copy of the most recent annual or quarterly report of the
           Company and such other reports and documents so filed by the Company,
           and (c) such other information as may be reasonably requested and as
           is publicly available in availing the holders of Shares of any rule
           or regulation of the Commission which permits the selling of any such
           securities without registration.






                                      -8-
<PAGE>   9
                  (e) Prior to the filing of the Registration Statement or any
amendment thereto (whether pre-effective or post-effective), and prior to the
filing of any prospectus or prospectus supplement related thereto, the Company
will provide each Selling Shareholder with copies thereof.

         4. MISCELLANEOUS.

                  (a) Notices required or permitted to be given hereunder shall
be in writing and shall be deemed to be sufficiently given if given in
accordance with the Purchase Agreement.

                  (b) Any term of this Agreement may be amended and the
observance of any term of this Agreement may be waived (either generally or in a
particular instance and either retroactively or prospectively), only with the
written consent of the Company and the holders of Warrants representing a
majority of the shares of Common Stock issuable upon conversion of the Notes.
Any amendment or waiver effected in accordance with this paragraph shall be
binding upon each Investor, each assignee or transferee of such Investor and the
Company.

                  (c) This Agreement shall be governed and construed under the
laws of the State of Connecticut without giving effect to the conflict of law
principles. The parties irrevocably consent to the exclusive jurisdiction of the
Superior Courts of the State of Connecticut at Hartford, Connecticut or the
United States District Court for the District of Connecticut.

                  (d) If one or more provisions of this Agreement are held to be
unenforceable under applicable law, such provision shall be excluded from this
Agreement and the balance of the Agreement shall be interpreted as if such
provision were so excluded and shall be enforceable in accordance with its
terms.

                  (e) This Agreement and the documents referred to herein
constitute the entire agreement hereto with respect to the subject matter hereof
among the parties, and no party shall be liable or bound to any other party in
any manner by any warranties, representations, or covenants except as
specifically set forth herein or therein.

         IN WITNESS WHEREOF, the Company has caused this Registration Agreement
to be duly executed by its authorized officer whose signature appears below.

                                  ACCENT COLOR SCIENCES, INC.



                                  By: /s/___________________________

                                  Name:  Charles E. Buchheit
                                  Title: President and Chief Executive Officer





                                      -9-
<PAGE>   10
                                   SCHEDULE A


                                    Investors


Orbis Pension Trustees Limited

The PMG Eagle Fund












                                      -10-