Copyright © 2006 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply.
This specification defines a subset of Cascading Style Sheets Level 2, revision 1 [CSS21] and CSS3 Module: Paged Media [PAGEMEDIA] for printing to low-cost devices. It is designed for printing in situations where it is not feasible or desirable to install a printer-specific driver, and for situations were some variability in the output is acceptable.
This profile is designed to work in conjunction with XHTML-Print [XHTMLPRINT] and defines a minimum level of conformance as well as an extension set that provides stronger layout control for the printing of mixed text and images, tables and image collections.
This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.
Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.
The (archived) public mailing list www-style@w3.org (see instructions) is preferred for discussion of this specification. When sending e-mail, please put the text “css-print” in the subject, preferably like this: “[css-print] …summary of comment…”
This document was produced by the CSS Working Group (part of the Style Activity).
This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.
This document contains the CSS Print Profile W3C Last Call Working Draft of 16 October 2006. The Last Call period ends on 20 November 2006.
Relative to the previous Candidate Recommendation, this version adds two new features ('fit' and 'fit-position'), synchronizes this profile with changes to XHTML-Print, removes redundancies with CSS3 Module: Paged Media and makes miscellaneous clarifications and editorial improvements.
All sections of this document are normative unless noted as informative.
This document specifies a profile of the Cascading Style Sheets, level 2, revision 1 (CSS 2.1) specification [CSS21] along with the CSS3 Module: Paged Media [PAGEMEDIA].
CSS 2.1 specifies how developers can author style sheets for presenting documents across multiple devices and media types. While this is very important, it is also important that authors have an understanding of what features are supported on these different devices. Likewise, it is important that similar devices operate in a similar manner. Otherwise, authors could need to develop style sheets for each version of each device -- raising the cost of content development and decreasing interoperability.
The CSS Print Profile specifies a conformance profile for printing in environments where it is not feasible or desirable to use a printer-specific driver. An example of such an environment is printing to low-cost printers from mobile phones. The profile identifies a minimum set of properties, values, selectors, and cascading rules to support these use scenarios. This profile was designed in conjunction with XHTML-Print ([XHTMLPRINT]) for low cost printers that may not have a full-page buffer and that generally print from top-to-bottom.
This profile also contains an enhanced layout extension set which supports more exacting page layouts and orientations. These features provide sufficient richness to print, for example, photo album pages from a digital still camera or print-targeted television content.
Conformance to this profile means that a user agent supports, at a minimum, the features defined in this specification. This subject is addressed in Section 2, Conformance below.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY" and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 (see [RFC2119]). However, for readability, these words do not appear in all uppercase letters in this specification.
The primary role of a profile is to define a subset of features that provides a minimal guarantee of interoperability. In the case of the CSS Print Profile, this guarantee is that a conforming user agent will support the features defined in this specification following the CSS 2.1 conformance clause ([CSS21] Section 3.2), recast and summarized below:
As with CSS 2.1, there are qualifications to this conformance clause:
It is RECOMMENDED that authors use this conformance profile to take advantage of forward compatibility. Authors MAY use style properties with an understanding that the cascading rules are processed correctly and that unknown properties and values are ignored. For example:
body { background-position: center center; background-position: 45% 55%; }
A printer that can accept percentage values for the background-position property will process the first background-position declaration and then replace that value with the second background-position declaration. A printer that cannot accept percentage values will process the first background-position declaration and ignore the second background-position declaration.
Some print applications require a more exacting page layout than is available from a minimally conforming printer (e.g., photo album pages or pages from a digital TV). The Enhanced Layout Extension increases the number of properties that a conforming printer MUST support and thereby the requirements of its memory and performance capabilities. These added CSS constructs are indicated with a "MUST" or an increased range of values, in the CSS Print-Enhanced columns below.
Printers supporting the Enhanced Layout Extension MAY also support an OPTIONAL, discoverable (via some means outside the scope of this document) Enhanced Layout Extension indicator.
In CSS 2.1, pattern matching rules determine which style rules apply to elements in the document tree [CSS21].
Consideration is given to low-cost printers that might not be able to store all the attributes of each element, but only keep the few that are necessary. Therefore, only Enhanced Layout Extension conforming printers MUST support attribute selectors.
The following table summarizes CSS Print Profile selector syntax. In addition to the selectors marked "MUST" in the CSS Print or CSS Print-Enhanced columns, the CSS Print Profile includes the CSS 2.1 grouping mechanism (See [CSS21] Section 5.2.1).
Pattern | Meaning | Selector type | CSS Print | CSS Print-Enhanced |
---|---|---|---|---|
* | Matches any element | Universal selector | MUST | MUST |
E | Matches any E element (i.e., any element of type E) | Type selectors | MUST | MUST |
E F | Matches any F element that is a descendant of an E element | Descendant selectors | MUST | MUST |
E > F | Matches any F element that is a child of an element E | Child selectors | MUST | MUST |
E[foo] | Matches any E element with the "foo" attribute set (whatever the value). | Attribute selectors | MAY | MUST |
E[foo="warning"] | Matches any E element whose "foo" attribute value is exactly equal to "warning". | Attribute selectors | MAY | MUST |
E[foo~="warning"] | Matches any E element whose "foo" attribute value is a list of space-separated values, one of which is exactly equal to "warning". | Attribute selectors | MAY | MUST |
E.classid | The same as E[class~=classid] | Class selectors | MUST | MUST |
E#myid | Matches any E element id equal to "myid". | ID selectors | MUST | MUST |
@page :first | Specifies style for the first page of a document | Page pseudo-classes | MUST | MUST |
The following table summarizes CSS Print Profile at-rule syntax.
at-rule | Function | CSS Print | CSS Print-Enhanced |
---|---|---|---|
@import | Imports an external style sheet. | MAY | MUST |
@charset | Defines character set for the style sheet. | MUST | MUST |
@media | Groups a set of style rules to apply only to one or more particular media. | MUST | MUST |
@page | Defines a (optionally named) page formatting context. | MUST | MUST |
@bottom-left-corner, @bottom-left, @bottom-center, @bottom-right, @bottom-right-corner |
Defines areas on the page within the running footer in the page's bottom margin [PAGEMEDIA] | MUST | MUST |
@top-left-corner, @top-left, @top-center, @top-right, @top-right-corner |
Defines areas on the page within the running header in the page's top margin [PAGEMEDIA] | MUST | MUST |
As with selectors, the properties a printer MUST support are similar to those that a mobile device MUST support ([CSSMOBILE], Properties) with the exception of those that don't apply to the page or are specifically targeted at media other than the page.
In some cases the allowable values for a printer are a subset of the full range of values to match the reduced memory and performance capabilities of a low-cost printer.
The following table summarizes CSS Print Profile properties and property values. Refer to CSS3 Module: Paged Media [PAGEMEDIA] for the definition of the image-orientation, fit, fit-position, and size properties and CSS 2.1 [CSS21] for the definition of all other properties and values.
Name | CSS Print | CSS Print-Enhanced | CSS Values | Initial value |
---|---|---|---|---|
'background' | background-color | inherit | ['background-color' || 'background-image' || 'background-repeat' || 'background-position'] | inherit | ['background-color' || 'background-image' || 'background-repeat' || 'background-attachment' || 'background-position'] | inherit | see individual properties |
'background-color' | MUST | MUST | <color> | transparent | inherit | transparent |
'background-image' | MAY | MUST | <uri> | none | inherit | none |
'background-position' | MAY | MUST | [ [ <percentage> | <length> ]{1,2} | [ [top | center | bottom] || [left | center | right] ] ] | inherit | 0% 0% |
'background-repeat' | MAY | MUST | repeat | repeat-x | repeat-y | no-repeat | inherit | repeat |
'border' | MAY | MUST | [ <border-width> || <border-style> || [<color> | transparent] ] | inherit | see individual properties |
'border-collapse' | MAY | MUST | collapse | separate | inherit | collapse |
'border-color' | MAY | MUST | [<color> | transparent]{1,4} | inherit | see individual properties |
'border-spacing' | MAY | MUST | <length> <length>? | inherit | 0 |
'border-style' | MAY | none, solid | <border-style>{1,4} | inherit | see individual properties |
'border-top' 'border-right' 'border-bottom' 'border-left' | MAY | MUST | [ <border-width> || <border-style> || [<color> | transparent] ] | inherit | see individual properties |
'border-top-color' 'border-right-color' 'border-bottom-color' 'border-left-color' | MAY | MUST | <border-color> | transparent | inherit | the value of the 'color' property |
'border-top-style' 'border-right-style' 'border-bottom-style' 'border-left-style' | MAY | none, solid | <border-style> | inherit | none |
'border-top-width' 'border-right-width' 'border-bottom-width' 'border-left-width' | MAY | MUST | <border-width> | inherit | medium |
'border-width' | MAY | MUST | <border-width>{1,4} | inherit | see individual properties |
'bottom' | MAY | MUST | <length> | <percentage> | auto | inherit | auto |
'caption-side' | MAY | MUST | top | bottom | left | right | inherit | top |
'clear' | MAY | MUST | none | left | right | both | inherit | none |
'clip' | MAY | MUST | <shape> | auto | inherit | auto |
'color' | MUST | MUST | <color> | inherit | depends on user agent |
'content' | inherit | [<string> | counter(pages†)]+ | inherit | [<string> | counter(pages†)]+ | [ <string> | <uri> | <counter> | attr(X) | open-quote | close-quote | no-open-quote | no-close-quote ]+ | inherit | empty string |
'counter-increment' | "pages"† | "pages"† | [ <identifier> <integer> ]+ | none | inherit | none |
'counter-reset' | MUST | MUST | [ <identifier> <integer>? ]+ | none | inherit | none |
'display' | MAY | inline | block | list-item | none |inherit | inline | block | list-item | run-in | compact | marker | table | inline-table | table-row-group | table-header-group | table-footer-group | table-row | table-column-group | table-column | table-cell | table-caption | none | inherit | inline |
'fit' | MAY | MUST | fill | hidden | meet | slice | fill |
'fit-position' | MAY | MUST | [ [<percentage> | <length> ]{1,2} | [ [top | center | bottom] || [left | center | right] ] ] | auto | 0% 0% |
'float' | MAY | MUST | left | right | none | inherit | none |
'font' | [ [ 'font-style' || 'font-weight' ]? 'font-size' [ / 'line-height' ]? 'font-family' ] | inherit | [ [ 'font-style' || 'font-variant' || 'font-weight' ]? 'font-size' [ / 'line-height' ]? 'font-family' ] | inherit | [ [ 'font-style' || 'font-variant' || 'font-weight' ]? 'font-size' [ / 'line-height' ]? 'font-family' ] | caption | icon | menu | message-box | small-caption | status-bar | inherit | see individual properties |
'font-family' | MUST* | MUST* | [[ <family-name> | <generic-family> ],]* [ <family-name> | <generic-family> ] | inherit | depends on user agent |
'font-size' | MUST ** | MUST ** | <absolute-size> | <relative-size> | <length> | <percentage> | inherit | medium |
'font-style' | MUST** | MUST ** | normal | italic | oblique | inherit | normal |
'font-variant' | MAY | MUST | normal | small-caps | inherit | normal |
'font-weight' | MUST ** | MUST ** | normal | bold | bolder | lighter | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | inherit | normal |
'height' | MUST | MUST | <length> | <percentage> | auto | inherit | auto |
'image-orientation' | MAY | MUST | <angle> | auto | auto |
'left' | MAY | MUST | <length> | <percentage> | auto | inherit | auto |
'letter-spacing' | MAY | MUST | normal | <length> | inherit | normal |
'line-height' | MUST | MUST | normal | <number> | <length> | <percentage> | inherit | normal |
'list-style' | MAY | MUST | [ 'list-style-type' || 'list-style-position' || 'list-style-image' ] | inherit | see individual properties |
'list-style-image' | MAY | MUST | <uri> | none | inherit | none |
'list-style-position' | MUST | MUST | inside | outside | inherit | outside |
'list-style-type' | disc, decimal, lower-alpha, upper-alpha, none and inherit | disc, decimal, lower-alpha, upper-alpha, none and inherit | disc | circle | square | decimal | decimal-leading-zero | lower-roman | upper-roman | lower-greek | lower-alpha | lower-latin | upper-alpha | upper-latin | hebrew | armenian | georgian | cjk-ideographic | hiragana | katakana | hiragana-iroha | katakana-iroha | none | inherit | disc |
'margin' | MUST | MUST | <margin-width>{1,4} | inherit | see individual properties |
'margin-top' 'margin-right' 'margin-bottom' 'margin-left' | MUST | MUST | <margin-width> | inherit | 0 |
'orphans' | MAY | MUST | <integer> | inherit | 2 |
'overflow' | MAY | MUST | visible | hidden | scroll | auto | inherit | visible |
'padding' | MAY | MUST | <padding-width>{1,4} | inherit | see individual properties |
'padding-top' 'padding-right' 'padding-bottom' 'padding-left' | MAY | MUST | <padding-width> | inherit | 0 |
'page' | MUST | MUST | <identifier> | auto | auto |
'page-break-after' | auto | always | inherit | auto | always | inherit | auto | always | avoid | left | right | inherit | auto |
'page-break-before' | auto | always | inherit | auto | always | inherit | auto | always | avoid | left | right | inherit | auto |
'page-break-inside' | MUST | MUST | avoid | auto | inherit | auto |
'position' | MAY | MUST ‡ | static | relative | absolute | fixed | inherit | static |
'right' | MAY | MUST | <length> | <percentage> | auto | inherit | auto |
'size' | [<length>{1,2}| letter | legal | ledger | A4 | A5 | A3 | B4 | B5 ] | auto | portrait | inherit | [<length>{1,2} | letter | legal | ledger | A4 | A5 | A3 | B4 | B5 ] | auto | portrait | landscape | inherit | [<length>{1,2} | letter | legal | ledger | A4 | A5 | A3 | B4 | B5 ] | auto | portrait | landscape | inherit | auto |
'table-layout' | MAY | MUST | auto | fixed | inherit | auto |
'text-align' | left | center | inherit | left | right | center | inherit | left | right | center | justify | <string> | inherit | depends on user agent and writing direction |
'text-decoration' | none, underline, and inherit | none, underline, and inherit | none | [ underline || overline || line-through || blink ] | inherit | none |
'text-indent' | MUST | MUST | <length> | <percentage> | inherit | 0 |
'text-transform' | MAY | MUST | capitalize | uppercase | lowercase | none | inherit | none |
'top' | MAY | MUST | <length> | <percentage> | auto | inherit | auto |
'vertical-align' | MAY | MUST1 | baseline | sub | super | top | text-top | middle | bottom | text-bottom | <percentage> | <length> | inherit | baseline |
'visibility' | MAY | MUST | visible | hidden | collapse | inherit | inherit |
'white-space' | MUST | MUST | normal | pre | nowrap | inherit | normal |
'widows' | MAY | MUST | <integer> | inherit | 2 |
'width' | MUST | MUST | <length> | <percentage> | auto | inherit | auto |
Table Note:
† Only the single identifier "pages" that represents the current page number is REQUIRED.
* It is RECOMMENDED that a printer minimally support "serif," "sans-serif," and "monospace" font families.
** The supported values SHOULD be appropriate to the fonts available to the printer.
‡ The printer MAY ignore positioned elements that are placed on the page before the position of the current element in the normal flow.
1 Vertical alignment is undefined across page boundaries.
The CSS Print Profile uses the same syntax as specified in Cascading Style Sheets, Level 2, revision 1 (CSS 2.1) [CSS21]. The CSS Print Profile uses a subset of the values used in CSS 2.1. Specifically:
Similarly, the CSS Print Profile requires that conforming user agents support the character encoding mechanisms specified in CSS 2.1 [CSS21]. Specifically:
In general, the CSS Print Profile uses the same cascading rules as in CSS 2.1. Specifically:
A CSS Print Profile conforming user agent SHALL be able to process media-dependent style sheets as specified in CSS 2.1 ([CSS21], Section 7). Specifically:
print
media type. all
media type. projection
or
handheld
). The following sections relax or otherwise modify the conformance requirements.
Authors are cautioned that the nesting of floats, divs, and absolutely positioned boxes within themselves, each other, and table cells should be used carefully, since the nesting depth of these constructs is printer and implementation dependent.
If page-break-inside: avoid
is specified for a long element and
the printer is unable to buffer the entire element before committing it to
paper, it SHOULD force a page break to occur before the long element and begin
the element starting at the top of the next page. If the long element starts at
the top of a page and exceeds the page length, the printer SHALL print as much
as possible on the first page and then resume that element on the next and
subsequent pages as REQUIRED
to preserve the content. A printer
MAY perform scaling
to fit the long element on a single page; but this is not recommended unless the
scaling required is minimal.
Due to a printer's mechanical limitations, the actual printable area of the page is often less than the page size. However, a printer SHOULD be guided by the page size value supplied by the CSS size property when choosing the media to print on.
See http://www.w3.org/TR/css3-page/#renderingpages in CSS3 Paged Media [PAGEMEDIA] for a discussion of fitting contents to media sheets.
This entire section is informative.
Appendix D of Cascading Style Sheets, Level 2, revision 1 ([CSS21], Appendix D) provides a sample style sheet. This sheet uses several properties that are not required of a conforming printer, even ones supporting the enhanced layout extensions (section 2.1).
Developers of printers that do not implement the enhanced layout facilities are encouraged but not required to adhere to the following implementation guidelines that address unsupported properties. These guidelines are presented to promote consistency between printer implementations.
The guidelines below are annotated to show derivation of the guideline from the Cascading Style Sheets, Level 2, revision 1 [CSS21] style sheet.
address, blockquote, body, dd, div, dl, dt, h1, h2, h3, h4, h5, h6,
hr, object, ol, p, pre,
and ul
elements
should be treated as if their display property were set to block
.
li
element should be treated as if its display property were set to list-items
.
table, tr, td, th,
and caption
, should have their
standard meaning and display treatments: table, table-row, table-cell,
and table-caption
.
base, br, html, head, link, meta, param, style
and title
should be treated as if their display property were set to none
.
a, abbr, acronym, b, big, cite, code, dfn, em, form, i, img,
input, kbd, option, samp, small, select, strong, sub, sup, textarea, tt,
and var
,
should be treated as if their display property were set to inline
.
A display property of inline
for the elements img, input, select,
and textarea
allows document authors a flexibility not available if their display property were block
.
ADDRESS, BLOCKQUOTE, BODY, DD, DIV, DL, DT, FIELDSET, FORM,
FRAME, FRAMESET, H1, H2, H3, H4, H5, H6, IFRAME, NOFRAMES,
OBJECT, OL, P, UL, APPLET, CENTER, DIR, HR, MENU,
{ display: block }
LI { display: list-item }
HEAD { display: none }
TABLE { display: table }
TR { display: table-row }
THEAD { display: table-header-group }
TBODY { display: table-row-group }
TFOOT { display: table-footer-group }
COL { display: table-column }
COLGROUP { display: table-column-group }
TD, TH { display: table-cell }
CAPTION { display: table-caption }
body
element should have 0.1 inch wide inset from the
left, top, right, and bottom of the printable area of the page.
Margin calculations will start from these offsets.
BODY { padding: 8px;
line-height: 1.33 }
sub
element should be treated as if its vertical-align property
were set to sub
. Similarly, the content of the sup
element should be treated
as if its vertical-align property were set to sup
.
SUB { vertical-align: sub }
SUP { vertical-align: super }
hr
element should be treated as if its area, as defined by its height and width, were outlined
by a one pixel thick, solid line.
The default line should be one pixel
high and the width of the containing box.
HR { border: 1px inset }
abbr
and acronym
elements should be rendered as scaled capital
letters, at approximately 75% of their size at the current font size. Upper case letters will be unchanged. Printers may
also choose to simply render lower case letters as upper case letters without scaling.
ABBR, ACRONYM { font-variant: small-caps;
letter-spacing: 0.1em }
h1, h2, h3, h4, h5,
and
h6
. Therefore, the printer is not
required to move the content of these elements from the bottom of
one page to the top of the next.
H1, H2, H3,
H4, H5, H6 { page-break-after: avoid;
page-break-inside: avoid }
ul, ol,
and
dl
elements.
UL, OL, DL { page-break-before: avoid }
hr
, should be treated as if the
element's border-style property were set to none
. visible
and the clip
property set to auto
.
static
.
fixed
.
The following style sheet is a modification of the sample sheet in Appendix D of Cascading Style Sheets, Level 2, revision 1 ([CSS21], Appendix D) and depends on the above guidelines.
th { font-weight: bolder; text-align: center } caption { text-align: center } body { line-height: 1.33 } h1 { font-size: 2em; margin: .67em 0 } h2 { font-size: 1.5em; margin: .83em 0 } h3 { font-size: 1.17em; margin: 1em 0 } h4, p, blockquote, ul, form, ol, dl { margin: 1.33em 0 } h5 { font-size: .83em; line-height: 1.17em; margin: 1.67em 0 } h6 { font-size: .67em; margin: 2.33em 0 } h1, h2, h3, h4, h5, h6, b, strong { font-weight: bolder } blockquote { margin-left: 40px; margin-right: 40px } i, cite, em, var, address { font-style: italic } pre, tt, code, kbd, samp { font-family: monospace } pre { white-space: pre } big { font-size: 1.17em } small, sub, sup { font-size: .83em } ol, ul, dd { margin-left: 40px } ol { list-style-type: decimal } ol ul, ul ol, ul ul, ol ol { margin-top: 0; margin-bottom: 0 } br { content: "\A" } @media print { @page { margin: 10% } blockquote, pre { page-break-inside: avoid } }
Developers of printers conforming to the enhanced layout extensions (section 2.1) MUST implement more of Cascading Style Sheets, Level 2, revision 1 [CSS21] than conforming printers, although the set of properties and their values is still less than complete.
Developers of printers are encouraged but not required to adhere to the following implementation guidelines that address unsupported properties.
table, tr, td, th,
and
caption
, should have their standard meaning and display
treatments: table, table-row, table-cell,
and
table-caption
. inset
value of the border-style property is not required.
h1, h2, h3, h4, h5,
and
h6
. Therefore, the printer
need not be concerned with moving the content
of these elements from the bottom of one page to the top of the next.
ul, ol,
and
dl
elements. The following style sheet is a modification of the sample sheet in Appendix D of [CSS21] and depends on the above guidelines.
address, blockquote, body, dd, div, dl, dt, form, h1, h2, h3, h4, h5, h6, object, ol, p, ul, hr, pr e { display: block } li { display: list-item } head { display: none } th { font-weight: bolder; text-align: center } caption { text-align: center } body { padding: 8px; line-height: 1.33 } h1 { font-size: 2em; margin: .67em 0 } h2 { font-size: 1.5em; margin: .83em 0 } h3 { font-size: 1.17em; margin: 1em 0 } h4, p, blockquote, ul, form, ol, dl, { margin: 1.33em 0 } h5 { font-size: .83em; line-height: 1.17em; margin: 1.67em 0 } h6 { font-size: .67em; margin: 2.33em 0 } h1, h2, h3, h4, h5, h6, b, strong { font-weight: bolder } blockquote { margin-left: 40px; margin-right: 40px } i, cite, em, var, address { font-style: italic } pre, tt, code, kbd, samp { font-family: monospace } pre { white-space: pre } big { font-size: 1.17em } small, sub, sup { font-size: .83em } hr { border: 1px } ol, ul, dd { margin-left: 40px } ol { list-style-type: decimal } ol ul, ul ol, ul ul, ol ol { margin-top: 0; margin-bottom: 0 } br { content: "\A" } @media print { @page { margin: 10% } blockquote, pre { page-break-inside: avoid } }
This section is informative.
This specification was prepared by the W3C CSS Working Group. The participants at the time of publication were:
List will be inserted when this document becomes a Recommendation.
This specification is based on the specification of the same name, CSS Print Profile [CSSPP] from the Printer Working Group, a program of and through the IEEE Industry Standards and Technology Organization, Inc. The editor wishes to express her gratitude to all those who contributed to it.