Copyright
Lincoln Cushing, Docs Populi https://www.docspopuli.org
Originally written as student paper at UC Berkeley SIMS
11/21/2000, updated 3/5/2007
This is a subject in perpetual change; please let author know of any
changes, corrections, or suggestions.
Protection of Digital Images on the Web
Introduction
“There is agreement among academics, educators, and librarians alike
about the rationale for creating ... a national digital library to
provide wider electronic access to knowledge and information. Such
access would (1) vastly enhance education, scholarship, arts, and
science; (2) preserve and make accessible unique primary materials
about our heritage; (3) make America more competitive in world markets;
(4) foster an informed citizenry.”
“The National Digital Library Program—A
Library for All Americans,” The Library of Congress, February 1995, p.
5. [1]
“Janus from
Brussels has told me that he has e-mailed your posters to a group of
college students who in turn have altered them with the help of an
Adobe graphics program and they have successfully turned their messages
around… The students are also creating a counter web site to
showcase the posters and to enlighten the international public about
the horrors of communism. Janus told me that the students have a
message for you of course translated from the Flemish which reads “What
are you going to do to us? Sue us? WE CAN SAY WE TOOK THE POSTERS FROM
THE PICTURE LIBRARY AT SCHOOL. YOU HAVE NO PROOF.”
e-mail from Serge
Goldberg to the Cuba Poster Project message board July 10, 2000;
emphasis exactly as written.
[2]
Any sharing or display of digital images on
the World Wide Web poses a risk for inappropriate copying and
use. Given the ease with which material can be swiped off the
screen and the huge numbers of people clicking through websites, is it
reasonable and appropriate for institutions such as libraries,
galleries, and museums to post anything at all? I would suggest that
the answer is a qualified yes; the benefits far outweigh the dangers if
the hosting institution truly understands the issues and diligently
adopts a methodology for protecting digitally-published images.
The issues involved transcend simple protection of the artifact, and
ultimately include the broad challenge of protecting the integrity of
the intellectual content.
Arguments for digitizing and
publishing images on the Web
There are many good reasons to put images up on the Web. From the
viewpoint of simple access, some oversized documents, such as posters,
are difficult for institutions to store in a way that allows access for
researchers. [3] Many materials are fragile and
suffer when handled, even by professional staff during routine
operations. Institutions may be inaccessible to the physically disabled
or geographically remote for those that would like to see their
holdings. Perhaps the most profound development is the tremendous
advantage that properly metadata-tagged digital images offer for
computer-assisted research. It is finally beginning to be
possible to rapidly assemble whole bodies of work where the original
artifacts reside in a multiplicity of physical locations. Institutions
have chosen to approach document digitization to meet a variety of
needs, including document conservation and document surrogates. The
practical contradiction emerges as being the tradeoff between high
resolution (at high cost and more taxing on storage devices, but with
more options for use) and moderate resolution (at lower cost but with
more limited uses). It is outside the scope of this paper to address
these tradeoffs, but at some point all image publishers will confront
the same issues regarding protection of digital images.
Why protect works at all?
The legal and ethical issues
surrounding the notion of intellectual property itself are beyond the
scope of this paper. However, it must be noted that much of this is
deeply contested terrain. At one end of the spectrum are those
that believe strongly that without rigorous laws protecting human
expression as property that intellectual creativity will wither through
lack of market incentives. At the other end are those that consider all
property theft, that acts of personal creativity are based on the
uncredited works of others, and that the commodification of creative
works has distorted the entire cultural landscape. This debate
has given rise to various approaches to crediting and describing
materials, ranging from conventional patents and copyrights to
“copyleft” [4] and deliberate description of
materials as being copyright-free.
Related to these issues is the concept of “fair use”, whereby under
U.S. law even copyrighted materials may be republished under certain
circumstances. This type of usage has been vital to the level of public
debate we take for granted, and must be taken into account when
considering how strictly one expects to protect published
material.
It is important to realize that some of the issues concerning
inappropriate copying of images are not unique to the digital
world. As brother Goldberg kindly reminds us in the e-mail above,
any good quality reproduction of an image in a catalog or book has the
potential to be “stolen”. Although this paper only describes approaches
for digital images, most of the approaches also can be applied to
offset reproductions.
Steps toward protection
Without protection, an organization
exposes itself to litigation on behalf of the authorized agent, risks
trampling the intellectual property rights of the original artist, and
jeopardizes the expense of time and money that such a project requires.
Opportunities for dealing with image protection surface most
prominently at three key points: acquisition, presentation, and
contractual use.
1. Acquisition. The moment images are first gathered is
usually the best time to establish authorized use. The artist and
any other relevant parties that may have claim or consideration in the
use of the image should sign a release form before the image is
documented. In practice, many organizations may wish to use material
for which no release (or an inadequate release) exists; in those cases
securing authorization from the artist or his/her estate is the proper
course of action.
2. Presentation. Images must be publicly displayed in a way
that both properly credits the originating artist and also clearly
describes legal limitations to image re-use by viewers. In addition,
technical and/or mechanical safeguards should be utilized that will
limit unauthorized use. These safeguards include image resolution,
watermarking, and encryption protections.
I. Image resolution
A common approach is simply to rely
on displaying tiny thumbnails. These small (~1x1.5" at 72 dpi) images
are adequate for getting a general impression of the item but are too
low resolution for any reasonable secondary use. Of course, the degree
to which such images are re-usable is subject to interpretation,
creativity, and hard work. An inexpensive inkjet color printer is
capable of producing remarkably good-looking copies from 72 dpi images
at 100% scale. However, the file size needed for reproducing the
same image at same scale for offset printing – say, for use in a
brochure or book – would require a resolution of at least 300 dpi, a
constraint that would considerably reduce the final size of the printed
image. It is also conceivable that a simple image could be enlarged and
cleaned up or re-created with applications such as Photoshop or
Illustrator; however, this is usually a lot of work, presumably making
it more trouble than it is worth.
II. Watermarking
Watermarked images offer a higher
degree of protection for images that are of sufficient resolution to be
potentially abused. They can be applied to static web images as well as
material released for review or reproduction. Various commercial
systems are available that allow some form of encoded identifier to
permanently accompany an image and verify its source. Watermarks
can either be visible or invisible.
A visible watermark (also known as “scarring”) is commonly used in
applications such as photograph catalogs, allowing the viewer to see
what the image is like before ordering a good copy. These embed a
semi-ghosted visual logo across the image, making commercial use
impractical. The advantage of this is that the mark is
unmistakably bound to the viewed image and the mark itself renders the
viewed image virtually useless for reproduction. One low-cost source
for this is H20marker [5], which allows for an
image or text to be overlaid onto a main image as a visible watermark
at variable levels of transparency and can accommodate batch
processing.
Invisible watermarks are more common in public information settings
such as digital libraries and galleries. Digimarc [6]
is one of the more popular applications; it is easy to use because its
code-embedding software is included with the ubiquitous
image-processing application Adobe Photoshop, and it offers an optional
web-spider searching feature that helps the owner learn of new web
postings that contain images with the owner's user identification. The
encryption involved in embedding the unique code in the image is robust
enough to survive even after resizing, cropping, and other graphic
torture. Scanning an encoded image even after it has been printed out
still reveals that the code persists [7]. One
limitation of this form of watermark is that it will only work with
JPEG images; GIFs cannot be so marked, though this rarely affects
important images.
It is important to note that watermarks cannot prevent the theft of an
image, but they can be extremely valuable for tracking abuse and
proving ownership once it has happened.
Encryption includes the range of
technical approaches that attempt to actually prevent the downloading
or capture of an image that is placed on a web server. The
simplest approaches are for static pages, the most common method for
displaying material on the web. One such approach involves simply
adding a blank layer to an HTML page [8]. Upon
requesting the viewed image be printed or copied, all that is
screen-scraped is the blank layer. A skilled and persistent web surfer
can bypass this technique, but it involves some effort to copy each
image and is generally immune from spiders. Another is to use a
simple Javascript to disable the right-click “Save image as” browser [9]. Unfortunately, this will not work on Mac
computers or on PCs if Java is turned off in the viewer’s web browser.
A more robust and elegant approach involves the use of server-side web
applications. These commercial services will block unauthorized
downloading of images by web spiders, may make screen capture
impossible, can encrypt cached images in the browser, and prevent
direct linking of images from another site. Secure Image v.2.1 by
Artistscope [10] offers software that offers a
protection firewall. Instead of the standard practice of placing an
image onto the html page, the image is first encrypted and then
inserted into a viewer that sits on the page replacing the image. The
image converter enables a preview of the images in a window for
selection, allows manipulation of size, and saves the newly encoded
images or batch. Homebrew versions of this sort of protection can
be built into any dynamically-generated website, such as one using a
Cold Fusion server to process requests from an Access database.
3. Contractual use.
Finally, any ultimate use of an image can be carefully described by
contract. Generally, use contracts include specific language regarding
the following subjects, if applicable:
1. Print reproduction conditions including print run, image size, color
or black and white, placement, length of use, and geographic
distribution, sale/subscription price.
2. Web reproduction conditions, including restrictions on allowing
direct links to the image from other sites and duration of use.
3. Image alteration, which can involve some restrictions (especially
for fine artwork) that limit the end user's latitude in manipulating
the image composition in any way, including flopping, cropping, and
changing proportions.
4. Crediting; often there are specific guidelines as to the expected
crediting of the artist, including name, date of creation, and title,
as well as where that credit should reside and in what format. It is
also not uncommon for supplementary information to be required, such as
credit for documentary photographer, location of original artwork,
image provider, participating artists, and original client.
5. Copyright protection is often specified, indicating exactly what
copyright data must be displayed and where.
6. Political restrictions; some vendors go so far as to try and limit
uses incompatible with their corporate mission. For example one
GettyOne image of Los Angeles graffiti includes the stated restriction
"Cannot be used worldwide for political causes or issues" [11].
One approach taken by a major institution (the Library of Congress) is
to place responsibility on the patron for any misuse. This is their
disclaimer:
“Division Responsibility: As a
publicly supported institution the Library generally does not own
rights to material in its collections. Therefore, it does not charge
permission fees for use of such material and cannot give or deny
permission to publish or otherwise distribute material in its
collections. It is the patron's obligation to determine and satisfy
copyright or other use restrictions (such as donor restrictions,
privacy rights, publicity rights, licensing and trademarks) when
publishing or otherwise distributing materials found in the Division's
collections.
It is the Division's responsibility to inform patrons of any donor
restrictions, that is, restrictions on use stipulated by the donor when
the collection was transferred to the Library. These agreements between
the Library and the donor about use of the collection are separate from
the legal rights of copyright, publicity, and privacy discussed in this
document. For example, the terms of the gift of the Work of Charles and
Ray Eames stipulates that works in the collection may not be published
or used commercially without the permission of the Eames Office. This
requirement is not amatter of copyright--it is possible that works in
the collection may be subject to copyrights held by others--but is the
result of the agreement made between the donor and the Library.
In addition, the Division's staff will attempt to inform patrons about
other restrictions when information is readily available
[12]."
Candidates for Image
Protection
Under which circumstances should
image protection be implemented? I would suggest that any display of
visual artwork that is not known to be in the public domain should have
several levels of security. Even sites with materials that offer
unique documentation of historic artifacts should consider basic
measures. Examples of websites with where protections are weak or
absent include the Free Speech Movement Archives (http://www.fsm-a.org/gallery-harawitz.html),
the Pictorial Highlights from UC Berkeley Archival Collections (http://sunsite.berkeley.edu/FindingAids/highlights.html),
and the Bancroft collection of Catalonian manuscripts (http://sunsite.berkeley.edu/cgi-bin/ebind2html/catalan/boethius?seq=1;cap).
The FSM site states that they are copyrighted by Howard Harawitz on the
same page as the displayed images. The Pictorial Highlights page
has a “Copyright © 1997 UC Regents. All rights reserved” tag at the
bottom, which is linked to the Digital Library SunSITE Copyright
Statement “Unless otherwise specified, copyright is held by the
University of California Regents. Copying is permitted for
noncommercial use by computerized bulletin board/conference systems,
individual scholars, and libraries. Express written permission is
required for any commercial use of the contents of this server.”
The Catalonian manuscripts page contains no reference to permissions
guidelines. None of these pages utilize any form of watermarking
or encryption.
Images on the Web can be
protected from abuse. The free exchange of ideas will only blossom as
long as predators are kept at bay and information providers do not feel
exploited. The many technical protection options available make
it easy for information managers of both large and small institutions
to assure high standards of service and control, and such measures must
be included in all digitization efforts.
Lincoln Cushing, Docs Populi https://www.docspopuli.org
Special thanks to Howard Besser for his comments on the original
version of this paper.
[1] From “Digitizing Historical Pictorial
Collections for the Internet,” by Stephen E. Ostrow, Council on Library
and Information Resources, February 1998 http://www.clir.org/pubs/abstract/pub71.html
[2] From author’s personal collection of
“hate e-mail”.
[3] An interesting and perhaps
counterintuitive consequence of this aspect of digital surrogates was
raised at a presentation in 2000 by Alice Prochaska, director of
digitization efforts by the British Library, in which she commented
that they have had the experience of well-done digital surrogates
fueling the demand for access to original artifacts.
[4] This includes a software
distribution approach spearheaded by the GNU project, http://www.gnu.org/copyleft/copyleft.html,
as well as a broader concept adopted by several publishers - see http://library.thinkquest.org/29500/copyleft.shtml
[5] http://www.cellspark.com/marker.html
[6] http://www.digimarc.com
[7] The persistence does
have limitations, but efforts by the author to squeeze the watermark
out were successful only after the image was degraded to the point that
its reproduction would not result in commercial duplication quality.
[8] see example at https://www.docspopuli.org/CubaWebCat/detail.np/detail-01.html
[9] see example above.
[10] http://www.artistscope.com/secure_image/default.htm
[11] http://www.gettyone.com/en-us/search/resultsmain.asp,
(enter “eb1307-001” Search Options); “Graffiti artist at graffiti yard,
Los Angeles, California, USA”, Stone photo agency, Robert Yager
photographer.
[12] http://lcweb.loc.gov/rr/print/195_copr.html
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