Guide to Writing Alt Text for Museum Websites and Guides

Alt text plays a vital role in making digital content accessible. While standards for generating alt text have become more common across publishing and web platforms, many remain underdeveloped, especially in settings—such as museums—that rely heavily on visual content. These environments present unique challenges not only because their audiences are diverse, but because artworks often require a more nuanced and interpretive approach than other types of images. 

In museum guides or websites, alt text may need to do more than simply name what’s visible in 60 words or less; it should also gesture toward mood, style, or formal elements like composition, color, and texture. Balancing accessibility with interpretive richness requires careful consideration of both language and audience. 

Using Formal Analysis to Guide Alt Text

When writing alt text for works of art, think beyond just naming what’s in the image. While you do want to describe the subject matter as thoroughly as possible, also describe how it looks. Good alt text draws on the principal elements of formal analysis: composition, line, color, texture, and scale. 

Think first about how you look at the work: 

• What are you drawn to first and how do you move through the image visually? 
• What stands out and how are different elements arranged? 
• Does the arrangement of elements evoke a certain mood or guide you through the work in a specific way? 

This doesn’t mean offering a full art historical analysis, but it does involve addressing form and content in a way that invites deeper engagement. It’s important to leave some room for individuals to interpret the work for themselves, and most crucially, to provide those who view and those who listen with equally compelling experiences. 

Remember that what you’re providing isn’t just an item to check off the ADA compliance list; you’re enhancing visitor experience and providing critical opportunities for engagement. As such, alt text should be concise but evocative, written to both mirror the pace of someone looking at an image and ensure consistent experiences for visitors of varying abilities. 

What to Include

As an art historian and editor, I’ve encountered a range of inconsistencies in how different publishers, institutions, disciplines, and individuals approach the process of writing alt text. However, most of the guides I’ve come across reinforce  principles consistent with those provided by Harvard’s digital accessibility team. Their guidelines offer clear and actionable best practices for writing alt text describing images that are purely decorative (e.g., logos, didactics, press images, or general images of a museum or its visitors).

Here are a few highlights with some added commentary geared more toward thinking about alt text for artworks:

• Keep it short, usually 1–2 sentences. Don’t overthink it.
  When it comes to supplementary images, this is great advice. When writing alt text for artworks, however, it’s important to think deeper about the function of the image. Think about how you’re recreating the experience of seeing the artwork in a collection; people tend to spend much more time with objects in a museum than they do with primarily decorative images, so more time should be afforded to the alt text as well. 
• Focus on key elements—why was this image included? What does it contribute?
  Think carefully about the context of the image and  consider whether the image is decorative or informational. While key elements for an image of visitors in the main entrance of a museum may be just the basics—”crowd of visitors in the main atrium of the museum”—key elements for artworks include subject, texture, composition, and color. Those details will need to be mentioned because they provide critical information that facilitates understanding.  
• Avoid saying “image of” or “picture of.”
  Especially when dealing with general images, these phrases crowd the limited space often allotted for alt text. It’s also redundant; the person using the alt text already knows that an image is being described to them. Focus on what they would otherwise not know. 
• But do name the image type when relevant (logo, painting, cartoon, etc.).
  The exception to the previous point is when you need to distinguish stylistic features, like in the case of a black-and-white photograph (an especially important detail for an artwork). While it is not always necessary to include this information—which often appears in captions—it is important to know, for example, whether the work is naturalistic or abstract, or whether paint has been applied smoothly or with a heavy impasto. 
• Don’t repeat adjacent or obvious text.
  For the same reason it’s not desirable to waste space on “image of”—avoid creating clutter for users of screen readers by repeating information they have access to elsewhere. Alt text should not repeat captions or information from other text or audio included around the image. The goal of alt text is to provide visual information that cannot otherwise be accessed. 
• End your alt text with a period.
  Screen readers understand punctuation and will pause accordingly. Ending alt text with a period, tells the screen reader to take a break before moving on, creating a more natural and lucid user experience. 

Navigating Space Limits

Despite the usefulness of these principles, technological constraints—such as how many characters can be added to an image—and varying awareness of accessibility best practices can result in inconsistent implementation. As a result, the quality and usefulness of alt text, especially for artworks or museum objects, can differ dramatically across platforms. 

Many systems were not developed with museums in mind: they limit available space because not much is needed for alt text describing things like logos, press images, or snapshots. These systems assume that the “important bits” are text-based and therefore already intelligible, while the layouts of digital museums are much more visual and thus inherently less accessible. So if space is limited, be sure to use it wisely and deliberately; if it isn’t, take advantage of the opportunity to provide rich, thoughtful, and intentional alt text.  

Another recurring challenge I’ve faced is the question of how much embedded text within an image should be transcribed. Though approaches vary, my recommendation is to consider the role that text plays and how legible it is. When text is a central feature of the work, either because of its proportions, clarity, or meaning in relation to the work, provide the full text if possible. When its function is more understated, describe the text visually—the role it plays in the composition and its formal traits (e.g., color, scale, form). 

Purpose Matters. So Does User Experience.

When writing alt text, always ask: what is the purpose of this image? Is it decorative or is it something viewers might want to engage with more critically? In a museum guide, for instance, some images—such as a photo of a gallery installation—may warrant a more considered description, while others—say, an image of visitors at a community program—might be more straightforward. 

Think about the museum-going experience itself. Some visitors move quickly through galleries, glancing at works; others linger, reading labels and companion texts closely. Your alt text should support both types of engagement while neither overwhelming users with a laundry list of items in the image nor omitting textural or compositional details. Remember that alt text isn’t just a technical requirement; it’s part of the interpretive experience. Like a good label or caption, it should offer clarity, invite curiosity, and make space for all users to connect with visual content in meaningful ways.