denise: Image: Me, facing away from camera, on top of the Castel Sant'Angelo in Rome (Default)
Denise ([staff profile] denise) wrote2013-01-31 12:40 am
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[tutorial] Writing Alt Text

Writing good alt text is an art, not a science. The same image can be described in different ways based on context, flow, and what aspects of the image you want to call to a listener's attention. The WHAT WG HTML Living Standard " Requirements for providing text to act as an alternative for images" has a collection of requirements for alt text, and WebAIM has a whole article on Appropriate Use of Alternative Text -- both of these are very useful resources! But it still takes practice to get really good at it.

So, let's practice, and see ways in which the same image in two different contexts might make you want to write the alt text differently.

Each of these sample images has two sets of text next to it: one formally-written piece (unless otherwise cited, it's from a relevant Wikipedia article), and a more casually-written sample that might be a blog post in which the image would appear.

Your task, should you choose to accept it, is to write relevant and useful alt text for the image in each context. Don't just look at the image and think in your head "oh, I'd do blah blah": actually write it out!

As you work, think about the differences in how you write the alt text in each context, and how different uses of the image make you want to call attention to different aspects of the image contents.

At the bottom of the page is a link to my version of the answers, with a brief explanation for each. I will reiterate that my answer is not necessarily everyone's answer! There are many, many ways to write alt text, and many people disagree as to which is the most useful.

Screenreader users: please note that I'm just using the alt text provided by Flickr's "get this HTML code" here, to avoid giving too many clues. Non-screenreader users: please don't just take Flickr's "get this HTML code" without altering it; it defaults to the title of the picture, which is usually fairly unhelpful for descriptive purposes!

I've turned comments off on this particular post, but they're open on the "answers" page, and if people would like to discuss their choices (or why they don't agree with my choices), feel free.

1. Endangered Beauty, by digitalART2

Endangered Beauty by digitalART2


The cougar (Puma concolor), also known as the puma, mountain lion, panther, or catamount, is a large cat of the family Felidae native to the Americas. Its range, from the Canadian Yukon to the southern Andes of South America, is the greatest of any large wild terrestrial mammal in the Western Hemisphere. An adaptable, generalist species, the cougar is found in every major American habitat type. It is the second heaviest cat in the Western Hemisphere, after the jaguar. Solitary by nature and nocturnal, the cougar is most closely related to smaller felines and is nearer genetically to the domestic cat than true lions.


The meeting was awful. Seriously awful. So awful I kept looking out the window and wishing for, like, a cougar to come and eat me or something so I didn't have to sit through the rest of the meeting. (Or, even better, a cougar to come and eat my manager.)

Then, of course, when I was driving home, I actually saw one lurking right on the edges of the park. (Not this guy in the pic, but close.) I very quickly said "I didn't mean it!" before the universe could decide I'd been serious about that being-eaten-by-a-cougar thing.

2. Unexpected by modernhypatia



Falconry is the hunting of wild quarry in its natural state and habitat by means of a trained bird of prey. There are two traditional terms used to describe a person involved in falconry: a falconer flies a falcon; an austringer (German origin) flies a hawk (Accipiter and some buteos and similar) or an eagle (Aquila or similar). In modern falconry the Red-tailed Hawk (Buteo jamaicensis) and the Harris hawk are often used. The words "hawking" and "hawker" have become used so much to mean petty traveling traders, that the terms "falconer" and "falconry" now apply to all use of trained birds of prey to catch game. In early English falconry literature, the word "falcon" referred to a female falcon only, while the word "hawk" or "hawke" referred to a female hawk. A male hawk or falcon was referred to as a "tiercel" (sometimes spelled "tercel") as it was roughly one third less than the female in size. Many contemporary practitioners still use these words in their original meaning. The practice of hunting with a conditioned falconry bird is also called "hawking" or "gamehawking".


My mother and I took a trip to Vienna, Bratislava, and Budapest in December of 2006.

This was taken in Budapest on the walls overlooking the Pest side of the river. I'd seen this man walking up (wearing the hat, which I believe covered the bird: he wasn't carrying it obviously), and a little while later came across him sitting there. Best guess is that that's a female Peregrine falcon.

I didn't talk to him, but the bird was beautifully still and gorgeous.[2]

3. Amber Beads by wessexarchaeology

Amber Beads


In general terms, amber beads in early Anglo-Saxon graves are widespread
throughout eastern and central England, with a separate and lesser concentration in Kent. The main distribution extends from Lincolnshire and Norfolk down to Wiltshire and Hampshire, with amber being comparatively rare in counties such as Essex and Surrey. The greatest quantity of amber in a single cemetery is approximately 981 beads at Sleaford (Lincs.), followed by Bergh Apton (Norf.) with 517, Linton (Cambs.) with around 404, Abingdon (Berks.) with 386, Collingbourne Ducis (Wilts.) with 340 and Long Wittenham (Berks.) with 339. Within cemeteries, quantities of amber beads per grave vary between one and 20 on average, but a few graves have very large quantities of amber beads. For example, Long Wittenham I grave 71 has 280 amber beads, compared with an average of five per person amongst those burials with amber beads. Similarly, Sleaford grave 143 contained around 250 amber beads in a cemetery with an average of around sixteen per person. This pattern is continued elsewhere: Linton has an average of fifteen beads per person, while grave 40 contains 147 beads, and Abingdon grave 60 has 114 beads with an average ofaround 23 beads. In each case, there is one grave containing a large number, one or two with around 50, while the remainder contain around the average for that cemetery, a pattern which suggests a degree of differential access to the supply ofamber beads. This may be either in the chronological sense, with amber becoming more common in the later burials, although fewer people were actually buried with it, or in the sense of one or two individuals controlling its supply and distribution. These interpretations are not mutually exclusive. Alternatively, the pattern may simply represent differences in fashion or personal preference. [1]


Went shopping last week in the jewelry district, which was pretty epic. The last place we stopped had just gotten a shipment of antique amber beads, which I splurged on. I really shouldn't have, but look at the color and inclusions on those: how could you resist?

I'm going to have to find something really amazing to pair these with and make pendants out of them. You don't want to know what I'm going to have to charge for the result, but seriously. How could you resist?

4. Rainbow by onegoodbumblebee



Library classification forms part of the field of library and information science. It is a form of bibliographic classification (library classifications are used in library catalogs, while "bibliographic classification" also covers classification used in other kinds of bibliographic databases). It goes hand in hand with library (descriptive) cataloging under the rubric of cataloging and classification, sometimes grouped together as technical services. The library professional who engages in the process of cataloging and classifying library materials is called a cataloguer or catalog librarian.

Depending on the size of the library collection, some libraries might use classification systems solely for one purpose or the other. In extreme cases a public library with a small collection might just use a classification system for location of resources but might not use a complicated subject classification system. Instead all resources might just be put into a couple of wide classes (Travel, Crime, Magazines etc.). This is known as a "mark and park" classification method, more formally called reader interest classification.


I went over to Susan's house after dinner last night, and when I walked into her living room I saw her bookshelves, and ... well, I can't even bring myself to describe it out loud; it hurts my soul that much. I did sneak a picture, though: look at this. JUST LOOK AT THIS. I have no words! How does she ever find anything?

I mean, it looks pretty enough, and it certainly does make the rest of her living room very colorful, but if I ever tried to do something like this, I'd toss the entire bookshelf on the floor the minute I tried to find a particular book and failed. I guess it works for her? But oh, man.

5. Red Phone Booth by Photomatt28

Red Phone Booth


The red telephone box, a telephone kiosk for a public telephone designed by Sir Giles Gilbert Scott, is a familiar sight on the streets of the United Kingdom, Malta, Bermuda and Gibraltar. Despite a reduction in their numbers in recent years, the traditional British red telephone box can still be seen in many places throughout the UK, and in current or former British colonies around the world. The colour red was chosen to make them easy to spot.


Look what I learned to do this week! This is a photo processing technique called "selective color" or "selective color replacement". It's a way for you to turn most of the photo black and white, but leave a specific element in color, to draw the eye. I've always loved the technique when I see it, but I was really surprised to find how easy it was.

(If you've always admired it just like I have but tried a few times to reproduce it in your image editing software and never figured out how: the trick doesn't involve filtering based on color, it involves copying the layer, turning the copy black & white, making sure the black & white copy is the top layer and the color copy is the layer underneath, and then slowly erasing the part of the (B&W) image you want to be color and revealing the color copy underneath. I've tried to figure out how to do that effect eight billion times and I never bothered to just look up a tutorial on how to do it! If I had, I would've realized earlier how easy it really is.)

Super Special Bonus Round: XKCD #936, "Password Strength"

For bonus points: how would you make this text-heavy, visually-complex image (that combines a cartoon and a data visualization aid) accessible? (You don't have to do it -- it's a lot of work! -- but figure out at least one option.)

xkcd 936: password strength


[1] Huggett, J.W. "Imported Grave Goods and the Early Anglo-Saxon Economy". Medieval Archaeology 32 (1988): 63-96 Web. 30 Jan 2013.
[2] Text here is from modernhypatia's description of the image on Flickr.

My version of the answers!