Publishers of technology books, eBooks, and videos for creative people

Home > Articles > Web Design & Development > Usability

Fluid Web Typography: Scale & Rhythm

  • Print
  • + Share This
Jason Cranford Teague shows how giving careful consideration to the measurements and scale you are designing for is what separates good Web typography from great Web typography.
This chapter is from the book

This chapter is from the book

  • Spacing and alignment control how the text is comprehended through space and time. Learn to control the tempo of your message and guide the reader from beginning to end.

The carpenter’s adage goes, “Measure twice, cut once.” Giving careful consideration to the measurements and scale you are designing for is what separates good Web typography from great Web typography. Size and space add texture and flow to your text, improving the readability and clarity of what you are trying to say.

When typographers talk about “motion” in type, they are describing the way that a well-composed text will compel the reader’s eye, moving it along from the beginning to the end with as little disruption as possible.

Web Measurements

Many designers want to define with exact precision the placement and size of elements in a Web design, similar to the way they might design for print or video. Those media are static—even video, which might move and be projected onto larger screens, but the aspect ratio does not change, so everything is scaled relatively. However, on the Web, you are dealing with a variable canvas, with its final size dependent on the whims of the reader.

Understand relative and absolute unit types

In Web design, sizes can be expressed in either absolute or relative terms. I’ll explain later in this section which to use for a particular situation, but first review the different measurement types and the units at your disposal.

Absolute value units (Table 4.1) are used to precisely control sizes, so that they do not vary, regardless of the viewer’s particular screen size, browser, or operating system. That said, even absolute units can vary between computers, generally because of operating system inconsistencies. This is the case with point sizes on the Mac versus on Windows.

Table 4.1 Absolute Value Units

unit

name

description

example

pt

point

72pt = 1 inch

12pt

pc

pica

1pc = 12pt

1pc

mm

millimeter

1 mm = .24pc

4.17 mm

cm

centimeter

1 cm = 10 mm

.42 cm

in

inch

1 in = 2.54 cm

.17 in

Relative value units (Table 4.2) have no fixed size, but instead are calculated relative to another value, such as the parent element’s size, or to the screen itself. Although less precise, relative values can be quickly scaled and changed without your having to recalculate all of their dependent values. For example, if you are using relative values to set the font size and line height, simply changing the font size will also change the line height proportionally.

Table 4.2 Relative Value Units

unit

name

description

example

%

percent

relative to size of parent element

150%

em

em

1em = 100%

1.5em

ex

x-height

relative to height of lowercase “x” in the font

4.17 mm

px

pixels

relative to monitor’s resolution

12px

Use points for print but never for screen

Although they’re standard for print design, I’d discourage you from using point sizes when defining font sizes for the screen. The problem is the inconsistency between Mac and Windows monitor resolution settings.

By definition, a point is 1/72 of an inch, or 72 points per inch (ppi). On a Mac, the computer assumes a monitor resolution of 72 dots per inch (dpi), which also coincides with the number of points per inch. On the other hand, Windows computers assume your monitor displays 96 dpi. If the system is set for large fonts, then Windows compounds the problem, assuming 120 dpi. Unix systems can vary between 75 and 100 dpi. These operating system assumptions result in the Mac OS rendering 18pt text at 18px text onscreen, the Windows OS rendering 18pt text at 24px onscreen, and Unix systems typically rendering 18pt text between 19px and 25px onscreen.

The upshot is that most Windows users see text that is 33% larger than text the same text viewed on a Macintosh if it was set using point sizes, rendering points all but useless for Web design onscreen. While most Mac browsers will try to adjust for this problem by increasing the base Mac font size to 16, some variance persists.

If you are designing a Web page for print (i.e., media="print"), however, then using point sizes is not only perfectly acceptable, but it is the preferred method for defining precise font sizes.

Use pixels for precision control, but know that you are taking control from the user

Although it is possible to precisely control the positions of elements with any of the absolute units, pixels are the most natural way to define measurements for screen-based media. Despite having a “relative” size, pixels behave absolutely in relation to the screen resolution. Many modern Web designs are specified in pixels because it is the most universal measurement regardless of screen size, OS, or browser. Like atoms in matter, pixels are irreducible as the smallest unit of meaningful distance on the screen—you can’t move something half a pixel.

While pixels give the designer precise control over where elements appear, they are not without their issues and inconsistencies. Most Web browsers allow users to enlarge text and zoom the page size, which is imperative for anyone with poor vision. Locking the font size with pixels or absolute values prevents Microsoft Internet Explorer from changing their size. Internet Explorer 7 goes some way in rectifying this limitation by allowing the entire page to be zoomed, but there is still some debate over pixels when accessibility is an issue.

Use ems and percentages for fluid design

In order to provide readers with the highest level of control over the content they are viewing, it is increasingly considered a best practice to define sizes (both font sizes and other length measurements) using relative units, especially ems.

The em (pronounced “m”) is the fundamental unit of measurement in typography. It is defined as the size of the type as computed relative to the current size of the type of the parent element. For example, if you set the font size of your Web page to 12px, then .5em=6px; 1em=12px; 1.5em=18px; 2em=24px. If you change the font size to 14px, then .5 em=7px; 1em=14px; 1.5em=21px; 2em=28px. So, really, ems work like percentage values for sizing fonts. However, percentage and ems work differently for margins and padding, with percentages being based on the parent’s width or height and ems still being based on the parent font size.

One reason ems are not a popular solution is that, since their computed size is relative to their parent’s size, you have to keep track of the current parent size to know how large or small the font will.

Despite their complexity, the advantage of using ems is that you can quickly change the scale of your design by simply changing a single font-size value. Since they are relative to the parent’s font size, changing the parent’s value changes the values for all of its children. Additionally, since some older browsers, most notably IE 6, will not resize text set in points, using ems guarantees that all of your readers get the same experience.

The bottom line is that whether you use pixels or ems is up to you. I recommend keeping them consistent within a document to avoid confusion.

  • + Share This
  • 🔖 Save To Your Account

Peachpit Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from Peachpit and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Peachpit products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites; develop new products and services; conduct educational research; and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email ask@peachpit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by Adobe Press. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.peachpit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020