How to describe complex things to the Blind

Images must be described for the blind as they cannot see them.

This is a complex task that unfortunately requires more time and brain power than classic alternative text on the web. In the following article I would like to show what you should pay attention to when describing pictures for the blind.

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Complex movements

First of all, it should be said that not only the blind, but many other persons benefit from verbal descriptions. That's not do-gooderism, it's service. Let's take the example of an athletic exercise. The best exercise book in the world struggles with two graphing problems:

It's two dimensional

At best, it can represent snapshots.

To 1. The human body is known to be three-dimensional. But an image can only ever be two-dimensional, in a book anyway. On the Internet one could still manage with all-round recordings, which I have not seen yet.

As a result, you can only record one part of the body at a time, the part that is facing the camera. Furthermore, the photographer has to decide whether he is taking a full-body shot or emphasizing a particularly important part of the body. With a full-body shot you can only see the details blurred, with a partial shot you can't see what the person is doing with their arms or legs or how they are holding their head. In a front shot, you can't see if he's straightened his back and so on.

To 2. If you don't have a video recording or a flip book, you can only depict states graphically. Since the space and patience of the athlete are limited, one is often satisfied with a representation of the starting position, the middle position and the final position. Most of the time it's even more spartan and you only show a shot of the most important position.

The procedural description is the most sensible form of description for such complex processes. This means that you first describe the starting position with all the relevant details: straight back, feet shoulder-width apart, hands stretched out straight with the backs of the hands pointing upwards and so on. If the starting position is the same for several exercises, it is sufficient to describe it once and give it a standard name such as "starting position" or "all-fours stand". If a part of the body remains unchanged during the exercise, you will notice this at the beginning: "The back always remains straight".

Then, little by little, the movements to be made with the body are described. Movements that are to occur in a specific order are described in that order. Movements that take place in parallel are of course described directly one after the other, unfortunately there is no other way.

It is also important to describe the posture that forms the end of the exercise. If this is the starting position, a reference to it is sufficient, otherwise the final position must be described in the same way as the starting position.

That sounds more complicated than it is. Mark Lauren did this in his book "You Are Your Own Gym" without knowing these instructions. There are countless yoga CDs that have to do this because persons are supposed to do the exercises only with the audio information.


Blind persons are excellent at describing paths they know to sighted persons. Sighted persons are abysmal at describing paths to the blind.

First of all, most sighted persons don't seem to know street names. This seems to have gotten worse with the navigation systems, but it is often in the nature of things. Everyone in Bonn knows where the Post Tower is and could find it without a map. But the address – hm – I have no idea. This also applies to other institutions such as the House of History, the Palais Schaumburg or the Kaufhof. Blind persons, on the other hand, often only know the address where they want to go. If they are strangers to the city, they don't know what landmarks are nearby either. It is therefore always advisable for blind persons to use Google Maps or similar services to find out whether prominent points such as shops or restaurants are close to what they are looking for.

The description of sighted persons is at best only ten meters accurate. I take everything literally, if someone says the building or the street is next to... then I go next to XY too. For a sighted person, however, "next to" can mean anything, for example within sight, but also in front of or behind XY.

Let's assume that the description is online and includes public transport. I take the Gustav Heinemann House in Bonn Tannenbusch as an example. So we take the 16/63 tram in the direction of Bonn West to the Tannenbusch Mitte stop. We get off at the bus stop and walk in the opposite direction to the exit. There is a shopping center in front of the train station, which you can walk past on the left. We reach a busy main road, which we do not cross, but turn right at this point and follow the road. From here we go straight on for a few hundred meters, crossing various side streets and a kind of park, but staying on the road. The street leads into a cross street, which is also heavily frequented.

Got it, I don't know the name of one or the other street, but I hope the system is clear. A precise indication of distance no longer makes sense from 20 - 30 meters. For the blind, however, it is particularly important that he knows that he is on the right path. Long but straight paths are easier than short but winding paths.

For passers-by who want to help, things are a little easier. Depending on how complex the route is, the blind person will have to ask more than once, so rough descriptions are completely sufficient. Precise descriptions such as "there" or "always straight ahead" are not helpful if the blind person has turned towards the abyss. Most persons can't accurately estimate a walk's duration or distance, but a rough estimate (50 meters, five minutes, etc.) is better than nothing.

You can also point out non-obvious dangers such as idle construction sites, thorns and similar traps for the blind.

The complex graphics

Today almost everyone has to deal with complex graphics. Creating a description for simple diagrams doesn't make sense to me if the values ​​of the diagram are available as a table. Relationships may not be apparent at a glance, but a description of such a factual object is inevitably too selective if it is purely verbal.

Complex graphics such as process flows, on the other hand, pose a greater challenge. First of all, it should be described what it is all about. The second step is a rough overview, for example the graphic can usually be divided into several sequences or sections that can be named first. This enables the blind person to visualize the rough structure. Then the most important elements or processes should be explained step by step. It makes sense to describe one process after the other if several processes run independently of each other.

It gets really complicated when several processes are running in parallel, but there are dependencies. In this case, too, I think it makes the most sense to first describe the processes individually and only then to show the dependencies.

Even if tables for body text are usually frowned upon, they offer interesting possibilities for our purpose. In this way, they make it possible to depict sequences. For example, a sequence could consist of one column, parallel elements are represented in one row. HTML tables rightly have a bad reputation, but they're easier to explore sequentially than regular body text and can represent parallelism better than nested lists and whatever else might be used for this purpose.

works of art

The most complex task is probably the description of a work of art . It is not difficult to describe what is depicted: blue mountains, brown horses, green meadows... But who does it makes no difference between a van Gogh or a postcard. There are hundreds of thousands of landscapes that look exactly like this.

It gets exciting where the pure description of content mixes with the interpretation. Here at the latest we reach the limits of what can be described. Of course, one can tell a birth blind person that the painter used different tones of red. One could try to describe to him what these differences mean, what optical effect they have and how one interprets the painter's intention, but this is difficult. But even if the blind person can understand this purely intellectually, he will never have the same feeling as the diligent art connoisseur who described the picture to him. It's basically the same with music, a piece of music can be described easily, as can one's own feelings about it, but that doesn't have the same effect on the listener, as long as he doesn't hear the piece himself. I don't see a way to solve the problem either. It's also the typical problem of audio descriptions for videos. Of course you can describe quite a lot, but a large part of the scenery and the acting are lost.

I often hear that this is a good actor and that is a bad actor. I am unable to judge that myself, on the contrary, I could not distinguish Arnold Schwarzenegger from Terrence Hill, because both have the same voice actor in Germany.

This may be why most blind persons prefer literature or radio to television and other more visual cultures.

Alt or Long Description?

The long description has been abolished in HTML5. It was originally intended for long descriptions, but never became widespread. This means that continuous text is the only way to describe graphics extensively.

The alternative text is in no case the right place for long descriptions. On the one hand, these texts cannot be navigated, the blind person can only listen to the description as a whole, which is exhausting with more than 100 characters when looking for a specific information within this text. On the other hand, long alternative texts, for example in text-image sections, disrupt the flow of reading.

Detailed descriptions are also likely to be too long for a caption. It therefore seems to make the most sense to place the texts directly in the body of the text. As already mentioned, all users benefit from such descriptions.

In cases where descriptions are really only of interest to blind persons or where the body text does not offer enough space due to limitations, a popup is the best place for long descriptions. You can do that for example with the detail summary element in HTML.

A new method is the detail tag. The detail tag is a tag that can be shown or hidden. It looks like this, here without the angle brackets:

detail summary Summary /summary div Details about the graphic /div /detail


My theory is that blind persons can get a reasonably good idea of ​​how an object is made from descriptions. The blind psychologist Zoltan Torey, who died in early 2014, tells in his biography that he could easily imagine the inside of a machine, the meshing of the gears, the mesh of belts and pistons and their interaction. With his imagination he was able to re-tile his roof. Blind women can apply blind make-up or put together their own clothes, which probably requires considerable visual imagination if you don't want to look like a bird of paradise.

The reason may be that blind persons will soon have to train to get their information from purely verbal descriptions. Since they have to do this every day, they almost inevitably become experts at it. Since those who were blind at birth did not have to develop any capacities for visual information processing, they are likely to be superior in this ability to those who later went blind.

There are sighted persons who like to guide the blind because this forces them to deal more intensively with works of art. usually one rushes through exhibitions as if it wouldn't make more sense to delve into one object than to look at 100, none of which left a lasting impression.

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