Last modified by Carina Enke on 20.02.2026

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Carina Enke 235.5 1 {{section}}
2 {{column width="60%"}}
Carina Enke 264.1 3 Websites today have to meet numerous requirements. Everyone wants to be able to access information on any device, anywhere, without restrictions or barriers. The use of mobile devices with smaller screens and sometimes slow internet connections is now commonplace. However, usability with alternative technologies, such as screen readers that work with voice output and keyboard operation, must also be ensured.
Carina Enke 62.1 4
Carina Enke 264.1 5 To meet all these requirements and make information accessible to everyone, there are a number of things to consider. The basic guidelines on usability and accessibility provide important orientation.
Carina Enke 62.1 6
Katharina Schönefeld (Admin) 204.1 7 {{info title="**Usability**"}}
Carina Enke 264.1 8 Usability is defined in the DIN EN ISO 9241-11 standard. A system must be able to be used by certain users in a certain context of use in order to complete work tasks effectively, efficiently and satisfactorily, and thus achieve certain goals.
Carina Enke 62.1 9
Carina Enke 264.1 10 The [[Website of the Nielsen Norman Group (EN)>>url:https://www.nngroup.com/articles/usability-101-introduction-to-usability/||shape="rect"]] provides an introduction and more information.
Carina Enke 62.1 11 {{/info}}
12
Carina Enke 264.1 13 {{info title="Accessibility"}}
14 The guidelines for fulfilling accessibility requirements can be found in the [[Web Content Accessibility Guidelines (WCAG 2.2)>>url:https://www.w3.org/TR/WCAG22/||shape="rect"]]. A German-language introduction to the topic of accessibility can be found on the website [["Einfach für alle">>url:https://www.einfach-fuer-alle.de/artikel/einfuehrung-barrierefreiheit/||shape="rect"]].
Carina Enke 186.1 15
Carina Enke 264.1 16 It is important to have an overview of the existing limitations of abilities and disabilities in order to understand the requirements. The[[ W3C Web Accessibility Initiative (WAI) >>url:https://www.w3.org/WAI/people-use-web/abilities-barriers/||shape="rect"]] website has a good English-language overview of the various abilities and barriers. Aktion Mensch provides a brief overview of forms of disability in German: [[Überblick über Behinderungsformen in deutscher Sprache>>url:https://www.aktion-mensch.de/inklusion/arbeit/fachkraefte-mit-behinderung-gewinnen/behinderungsformen||shape="rect"]].
Carina Enke 62.1 17 {{/info}}
18
Carina Enke 264.1 19 In OPAL and ONYX, authors can create and design various types of content. Among other things, you can use the text editor to provide descriptions and page content in the course. We have prepared some tips and further content for you.
Carina Enke 62.1 20
Carina Enke 236.6 21
Carina Enke 235.2 22 {{/column}}
Carina Enke 62.1 23
Carina Enke 235.2 24 {{column width="30%"}}
Carina Enke 264.1 25 {{panel title="Content"}}
Carina Enke 236.6 26 {{toc start="2" depth="3"/}}
Carina Enke 236.5 27 {{/panel}}
28
Carina Enke 264.1 29 {{panel title="Related Topics"}}
30 * [[Text editor>>doc:LMS.Benutzerhandbuch OPAL.Lehren.Weitere Funktionen.Texteditor.WebHome]]
31 * [[Use your own course layout in OPAL>>doc:LMS.Benutzerhandbuch OPAL.Lehren.Kurs.Kurseinstellungen.Kurslayout.WebHome]]
Carina Enke 236.5 32 {{/panel}}
Carina Enke 235.5 33 {{/column}}
34 {{/section}}
Carina Enke 236.3 35
Katharina Schönefeld (Admin) 203.1 36
Carina Enke 264.1 37 == Course-related accessibility statement ==
Carina Enke 258.2 38
Carina Enke 264.1 39 Public bodies, including state universities and schools, are legally obliged to produce an accessibility statement for their digital offerings. This statement describes the extent to which accessibility requirements are met and, where applicable, identifies areas that are not accessible. Further information can be found on the official website for the accessibility statement for web and app applications of the Federal Government.
Carina Enke 258.2 40
Carina Enke 264.1 41 A declaration at the software level covers the functions of the learning platform, but not the content of individual courses. However, since an OPAL course consists mainly of learning materials for which the course coordinators are responsible, it makes sense to provide a course-related accessibility statement.
Carina Enke 258.2 42
43
Carina Enke 264.1 44 To make it easier for teachers to create such a statement, TU Dresden provides the LMS Check Generator for accessibility. The tool enables course administrators to:
Carina Enke 258.2 45
Carina Enke 264.1 46 * create a course-specific accessibility statement,
47 * identify potential barriers in texts, media and interactive content,
48 * provide support for the accessible design of teaching materials.
Carina Enke 258.2 49
Carina Enke 264.1 50
51
52 The tool guides you step by step through the creation of the declaration. The person responsible selects the course modules used in the course and then receives a checklist for the content. The generated declaration is provided as an accessible HTML file and can be embedded in the course as a page using the ‘Single Page’ course module. This means that the declaration is directly available in the course and easy for learners to find.
53
54 {{panel title="Further information"}}
55 * LMS Check Generator tool for accessibility from TU Dresden: [[https:~~/~~/lms-check.inf.tu-dresden.de/checklist?lang=en>>url:https://lms-check.inf.tu-dresden.de/checklist?lang=en]]
56 * Federal government information on accessibility declarations for web and app applications: [[https:~~/~~/www.barrierefreiheit-dienstekonsolidierung.bund.de/Webs/PB/DE/barrierefreie_it>>https://www.barrierefreiheit-dienstekonsolidierung.bund.de/Webs/PB/DE/barrierefreie_it/uebergreifende-anforderungen-web-und-app/erklaerung-zur-barrierefreiheit/erklaerung-zur-barrierefreiheit-node.html]]
Carina Enke 261.1 57 {{/panel}}
Carina Enke 258.2 58
59
Carina Enke 264.1 60 == Tips for designing content ==
Carina Enke 261.1 61
Carina Enke 264.1 62 === How do I structure content? ===
Carina Enke 258.2 63
Carina Enke 264.1 64 When structuring texts on websites or in documents, it makes sense to use books or articles as a guideline. The headlines, bulleted lists, table of contents and visual highlighting used there help to improve readability, skimming or scanning with the eyes, and, therefore, make it easier to find relevant information quickly. These elements also help users to find their way around the site. In addition to visual structuring through design, technically correct structuring by means of suitable HTML elements is also necessary. This is particularly relevant for accessibility, as screen readers and other assistive technologies transmit information based on HTML code and provide various functions.
Carina Enke 258.2 65
Katharina Schönefeld (Admin) 203.1 66 {{info}}
Carina Enke 264.1 67 OPAL's integrated [[Text editor Tiny MCE>>doc:LMS.Benutzerhandbuch OPAL.Lehren.Weitere Funktionen.Texteditor.WebHome]] helps you to structure your content correctly without having to learn HTML.
Carina Enke 62.1 68 {{/info}}
69
Carina Enke 264.1 70 === Headings ===
Carina Enke 62.1 71
Carina Enke 264.1 72 Headings should not be created by changing the font size or using formatting such as bold, but rather using the HTML elements <h1>, <h2>, <h3> to <h6>. The element hierarchy (e.g. <h2> follows <h1>) must be maintained.
Carina Enke 258.2 73
Katharina Schönefeld (Admin) 203.1 74
Carina Enke 264.1 75 ==== Formats in the Tiny MCE text editor ====
Katharina Schönefeld (Admin) 209.1 76
Carina Enke 241.2 77 [[image:attach:Texteditor-Formate-Überschriften_de.png||data-xwiki-image-style="img-screen" data-xwiki-image-style-border="true" width="500"]]
Carina Enke 62.1 78
Katharina Schönefeld (Admin) 209.1 79
Carina Enke 264.1 80 ==== HTML code for headings ====
Carina Enke 62.1 81
82 {{code language="xml"}}
Carina Enke 264.1 83 <h1>heading 1. hierarchy</h1>
84 <h2>heading 2. hierarchy</h2>
85 <h3>heading 3. hierarchy</h3>
86 <h4>heading 4. hierarchy</h4>
87 <h5>heading 5. hierarchy</h5>
88 <h6>heading 6. hierarchy</h6>
Carina Enke 62.1 89 {{/code}}
90
Carina Enke 264.1 91 === Paragraphs and highlighting ===
Carina Enke 62.1 92
Carina Enke 264.1 93 Paragraphs, quotations or highlighted text in boxes help to break up a text and allow readers to jump to the relevant information if necessary.
Carina Enke 258.2 94
95
Carina Enke 264.1 96 ==== Formats in the Tiny MCE text editor ====
Katharina Schönefeld (Admin) 203.1 97
Carina Enke 264.1 98 [[image:attach:Texteditor-Formate-Absätze-Hervorhebungen_de.png||data-xwiki-image-style="img-screen" data-xwiki-image-style-border="true" width="500"]]
Carina Enke 62.1 99
Carina Enke 264.1 100 ==== ====
Carina Enke 258.2 101
Carina Enke 264.1 102 ==== HTML code for paragraphs ====
Carina Enke 258.2 103
Carina Enke 62.1 104 {{code language="xml"}}
Carina Enke 264.1 105 <p>paragraph</p>
106 <blockquote>quote</blockquote>
Carina Enke 62.1 107
108 {{/code}}
109
Katharina Schönefeld (Admin) 219.1 110 {{warning}}
Carina Enke 264.1 111 The elements <div> and <span> have no meaning (semantics) and should only be used, for example, to realize the design via CSS or dynamic adjustments via JavaScript.
Katharina Schönefeld (Admin) 219.1 112 {{/warning}}
Carina Enke 62.1 113
Carina Enke 264.1 114 === Lists ===
Carina Enke 62.1 115
Carina Enke 264.1 116 Lists can be used to present information clearly, briefly and concisely. Choose between unordered and ordered or numbered lists.
Carina Enke 258.2 117
Carina Enke 62.1 118 {{column}}
Carina Enke 264.1 119 ==== Lists in the Tiny MCE text editor ====
Carina Enke 62.1 120
Carina Enke 248.1 121 [[image:attach:Texteditor-Listen.png||data-xwiki-image-style="img-screen" data-xwiki-image-style-border="true" width="500"]]
Carina Enke 62.1 122 {{/column}}
123
124 {{column}}
Carina Enke 264.1 125 ==== HTML code for lists ====
Carina Enke 62.1 126
Carina Enke 264.1 127 {{code language="xml" title="unordered list"}}
Carina Enke 62.1 128 <ul>
Carina Enke 264.1 129 <li>list entry</li>
130 <li>list entry</li>
131 <li>list entry</li>
Carina Enke 62.1 132 </ul>
133
134 {{/code}}
135
Carina Enke 264.1 136 {{code language="xml" title="ordered list"}}
Carina Enke 62.1 137 <ol>
Carina Enke 264.1 138 <li>list entry</li>
139 <li>list entry</li>
140 <li>list entry</li>
Carina Enke 62.1 141 </ol>
142
143 {{/code}}
144 {{/column}}
Katharina Schönefeld (Admin) 214.1 145
Katharina Schönefeld (Admin) 203.1 146
Carina Enke 264.1 147 === Tables ===
Katharina Schönefeld (Admin) 203.1 148
Carina Enke 264.1 149 ==== Using tables ====
Katharina Schönefeld (Admin) 214.1 150
Carina Enke 264.1 151 Please use tables only to present data in tabular form. Tables should not be used to display text or other content side by side or in “columns” for visual reasons (layout tables).
Katharina Schönefeld (Admin) 214.1 152
Carina Enke 264.1 153 It is worth considering whether a table is necessary or whether the content could be presented more simply, e.g. by means of a list.
Katharina Schönefeld (Admin) 214.1 154
155 {{info}}
Carina Enke 264.1 156 On small screen devices (e.g. smartphones) and when zoomed in (e.g. 300%), tables are often not displayed in full. As a rule, content should not be cut off. Therefore, check the display on different devices and different zoom levels, and never assign tables an absolute width (e.g. 700px).
Katharina Schönefeld (Admin) 214.1 157 {{/info}}
158
Carina Enke 264.1 159 ==== Table headings (Caption) ====
Katharina Schönefeld (Admin) 214.1 160
Carina Enke 264.1 161 Each table should have a heading that provides a brief summary of its content. You can use the HTML element <caption> for this purpose.
Katharina Schönefeld (Admin) 214.1 162
Carina Enke 264.1 163 In the Tiny MCE text editor, you can activate the table caption in the **table properties**. When you do this, some text will appear above the table, which you can change to match your content.
Katharina Schönefeld (Admin) 214.1 164
Carina Enke 264.1 165 ===== =====
Katharina Schönefeld (Admin) 214.1 166
Carina Enke 264.1 167 ===== **How to activate table captions in the Tiny MCE text editor** =====
Carina Enke 258.2 168
Carina Enke 253.2 169 [[image:Texteditor-Tabellen-Beschriftung_de.png||alt="Beschriftung für Tabellen aktivieren im Dialog Tabelleneigenschaften im Texteditor (Screenshot)" data-xwiki-image-style="img-screen" data-xwiki-image-style-border="true" width="500"]]
Katharina Schönefeld (Admin) 214.1 170
Carina Enke 264.1 171 ===== =====
Katharina Schönefeld (Admin) 214.1 172
Carina Enke 264.1 173 ===== **HTML code for captions** =====
174
Katharina Schönefeld (Admin) 214.1 175 {{code language="html" layout="LINENUMBERS"}}
176 <table>
Carina Enke 264.1 177 <caption>presentations on group work</caption>
Katharina Schönefeld (Admin) 214.1 178 ...
179 </table>
180 {{/code}}
Katharina Schönefeld (Admin) 215.1 181
182
Carina Enke 264.1 183 ==== Column and row headings ====
Katharina Schönefeld (Admin) 215.1 184
Carina Enke 264.1 185 Cells for headings (header cells) should be distinguished from data cells not only by design, but also by HTML. Header cells in tables are therefore marked with the HTML tag <th>, data cells with <td>.
Katharina Schönefeld (Admin) 215.1 186
Carina Enke 264.1 187 You can additionally link the header cells to the data cells via the ‘scope’ attribute. This ensures that your headings are assigned to the rows or columns and that the output via screen readers is correct.
Katharina Schönefeld (Admin) 215.1 188
Carina Enke 264.1 189 In the Tiny MCE text editor, you can use the **cell properties** to define your selected cells as headings and assign them to columns or rows.
Katharina Schönefeld (Admin) 215.1 190
Carina Enke 264.1 191 * To do this, select your preferred cells and open the **cell properties** via the menu (Table > Cell > Cell Properties).
192 * Now select ‘Header cell’ in the dialogue box under ‘Cell type’.
193 * Select ‘Column’ from the ‘Scope’ option.
194 * Repeat this action if you use row headings in addition to column headings. In this case, select ‘Line’ under the ‘Scope’ option.
Katharina Schönefeld (Admin) 215.1 195
Katharina Schönefeld (Admin) 218.1 196 {{warning}}
Carina Enke 264.1 197 Please do not leave your header cells empty.
Katharina Schönefeld (Admin) 218.1 198 {{/warning}}
199
Carina Enke 264.1 200 ===== **How to define header cells in the Tiny MCE text editor** =====
Katharina Schönefeld (Admin) 215.1 201
Carina Enke 264.1 202 [[image:Texteditor-Tabellen-Zelleneigenschaften_de.png||alt="Screenshot einer Seite mit einer Tabelle im Texteditor Tiny MCE. Die Kopfzeilen der Tabelle sind markiert und der Weg zu den Zelleneigenschaften ist hervorgehoben." data-xwiki-image-style="img-screen" data-xwiki-image-style-border="true" height="320" width="660"]] [[image:Texteditor-Tabellen-Zelleneigenschaften-Typ-Gültigkeitsbereich_de.png||alt="Screenshot des Dialogs Zelleneigenschaften. Hervorgehoben sind die Optionen Zellentyp und Gültigkeitsbereich." data-xwiki-image-style="img-screen" data-xwiki-image-style-border="true" height="320" width="323"]]
Carina Enke 258.2 203
204
Carina Enke 264.1 205 ===== **How to mark header cells in HTML** =====
Katharina Schönefeld (Admin) 215.1 206
207 {{code language="html" layout="LINENUMBERS"}}
208 <table>
Carina Enke 264.1 209 <caption>presentations on group work</caption>
Katharina Schönefeld (Admin) 215.1 210 <thead>
211 <tr>
Carina Enke 264.1 212 <th scope="col">date</th>
213 <th scope="col">time</th>
214 <th scope="col">topic</th>
215 <th scope="col">place</th>
Katharina Schönefeld (Admin) 215.1 216 </tr>
217 </thead>
218 <tbody>
219 <tr>
220 <td>04.03.</td>
Carina Enke 264.1 221 <td>10 - 11 a.m.</td>
222 <td>sustainability<td>
223 <td>room3b</td>
Katharina Schönefeld (Admin) 215.1 224 </tr>
225
226 ...
227
228 </tbody>
229 </table>
230 {{/code}}
Katharina Schönefeld (Admin) 218.1 231
Carina Enke 264.1 232 {{panel title="Further information"}}
233 * [[Steps towards an inclusive communication design (legibility.info)>>url:https://www.leserlich.info/||shape="rect"]]
Carina Enke 257.1 234 * [[HTML als Auszeichnungssprache / Semantik (SELFHTML-Wiki)>>https://wiki.selfhtml.org/wiki/HTML/Tutorials/Entstehung_und_Entwicklung#HTML_als_Auszeichnungssprache||shape="rect"]]
Katharina Schönefeld (Admin) 203.1 235 {{/panel}}
236
Carina Enke 258.2 237
238
Carina Enke 264.1 239 === How can texts be made easy to read? ===
Katharina Schönefeld (Admin) 203.1 240
Carina Enke 264.1 241 Font, font size, character and word spacing, line length and many other factors influence the readability of texts.
Katharina Schönefeld (Admin) 203.1 242
Carina Enke 264.1 243 * Make sure to use **common fonts** (like Arial) and avoid fancy or hard-to-read ones.
244 * The **font size** for large screens should be between 18px and 26px. For small devices, such as smartphones, you should use smaller font sizes because the device is usually closer to the eye.
245 * The **line spacing** should be at least 120% of the font size, preferably 150%.
246 * The **line length** should be between 45 and 80 characters per line, including punctuation and spaces.
Carina Enke 186.1 247
Carina Enke 264.1 248 Please keep in mind that font size, line spacing, and line length depend on both the font and the device you're using.
Katharina Schönefeld (Admin) 203.1 249
Carina Enke 255.2 250 {{info}}
Carina Enke 264.1 251 Check the readability of your texts on various devices and have them evaluated by other people. Ideally, by your users. Involve people with visual impairments or cognitive impairments as well as those with learning disabilities.
Katharina Schönefeld (Admin) 203.1 252 {{/info}}
Carina Enke 186.1 253
Carina Enke 264.1 254 {{panel title="Further information"}}
255 * [[Steps towards an inclusive communication design (legibility.info)>>url:https://www.leserlich.info/||shape="rect"]]
256 * [[Font size calculator (legibility.info)>>url:https://www.leserlich.info/werkzeuge/schriftgroessenrechner/index.php||shape="rect"]]
Katharina Schönefeld (Admin) 203.1 257 {{/panel}}
258
Carina Enke 235.3 259
Katharina Schönefeld (Admin) 203.1 260
Carina Enke 264.1 261 === How should links be set? ===
Katharina Schönefeld (Admin) 203.1 262
Carina Enke 264.1 263 Links need meaningful titles and should describe the purpose or destination of the link. Ambiguous link texts such as ‘more’, “here” or ‘read more’ should be avoided. Relevant information about the format or size of a file (e.g. for a download link) should also be included in the linked text.
264
Carina Enke 62.1 265 {{info}}
Carina Enke 264.1 266 A link has to stand on its own and still describe the destination or purpose well enough.
Katharina Schönefeld (Admin) 203.1 267 {{/info}}
Carina Enke 62.1 268
Carina Enke 235.3 269
Katharina Schönefeld (Admin) 203.1 270
Carina Enke 264.1 271 === What should be considered when using media? ===
Katharina Schönefeld (Admin) 203.1 272
Carina Enke 264.1 273 When using media, consider not only storage consumption and loading times, but also its accessibility on the go, e.g. on a smartphone with a poor internet connection. Ensure that information is always available via a second channel, such as text.
Katharina Schönefeld (Admin) 203.1 274
Carina Enke 264.1 275 Here are some tips you might find useful regarding accessibility and mobile compatibility.
Carina Enke 186.1 276
Carina Enke 264.1 277 ==== File size ====
Carina Enke 186.1 278
Carina Enke 264.1 279 * For photos, JPEG format should be preferred and medium to high quality should be selected depending on the image content.
280 * Images should not exceed a file size of 100-200kB.
281 * Save the images directly in the required image size (width x height) with a resolution of 72 dpi.
282 * For very large files, such as videos, we recommend embedding them via an external tool (e.g. Videocampus Sachsen, YouTube, Vimeo, etc.).
283
Carina Enke 186.1 284 {{info}}
Carina Enke 264.1 285 Common image editing programmes and online tools can help to compress images without any visible loss of quality.
Carina Enke 186.1 286 {{/info}}
287
Carina Enke 264.1 288 ==== Captions ====
Carina Enke 186.1 289
Carina Enke 264.1 290 Captions or titles provide additional information about images. A title is necessary if important information about the image needs to be conveyed. Unlike image descriptions (alternative text), titles are also accessible to sighted users.
Katharina Schönefeld (Admin) 203.1 291
Carina Enke 264.1 292 Use the following HTML code to make the image and image title accessible:
Katharina Schönefeld (Admin) 203.1 293
Carina Enke 264.1 294 **Caption with the HTML elements figure and figcaption**
Katharina Schönefeld (Admin) 203.1 295
Katharina Schönefeld (Admin) 221.1 296 {{code language="html" layout="LINENUMBERS"}}
Carina Enke 186.1 297 <figure>
Carina Enke 264.1 298 <img src="..." alt="alternative text">
299 <figcaption>title / caption</figcaption>
Carina Enke 186.1 300 </figure>
Katharina Schönefeld (Admin) 203.1 301 {{/code}}
Carina Enke 62.1 302
Carina Enke 258.2 303
304
Carina Enke 264.1 305 ==== Alternative text (alt text) ====
Katharina Schönefeld (Admin) 203.1 306
Carina Enke 264.1 307 You should always provide alternative text for images that are relevant to the content of a page. Alt text is read out by screen readers and, therefore, accessible to blind people. Even if the images on the page are disabled or cannot be loaded due to a slow internet connection, the information can still be conveyed despite the missing image.
Katharina Schönefeld (Admin) 203.1 308
Carina Enke 264.1 309 **The following should be kept in mind when providing alt text for images:**
Katharina Schönefeld (Admin) 203.1 310
Carina Enke 264.1 311 * Keep it short: The alternative text should only contain the most important information. A useful guideline is 125 characters.
312 * Describing information: Only describe information that is relevant to the context (e.g. the text) and that the image is intended to convey.
313 * Images that are used primarily for design purposes should not be given alt text (empty alt attribute). In the text editor, you can mark these images as decorative.
Carina Enke 62.1 314
315 {{info}}
Carina Enke 264.1 316 Imagine you are describing a picture of a person on the phone. Which details would you mention, and which would you leave out because they are not relevant in this context?
Carina Enke 62.1 317 {{/info}}
318
Katharina Schönefeld (Admin) 208.1 319
Carina Enke 264.1 320 ===== How to store alternative text in the Tiny MCE text editor =====
Carina Enke 62.1 321
Katharina Schönefeld (Admin) 234.1 322 [[image:Texteditor-Bilder-Alternativtext.png||data-xwiki-image-style="img-screen" data-xwiki-image-style-border="true" width="500"]]
Carina Enke 62.1 323
Katharina Schönefeld (Admin) 208.1 324
Carina Enke 264.1 325 ===== HTML code for alt text =====
Katharina Schönefeld (Admin) 208.1 326
Katharina Schönefeld (Admin) 196.1 327 {{code}}
Katharina Schönefeld (Admin) 197.1 328 <img ... alt="Der Schaum auf einem Kaffee bildet ein schreiendes Gesicht." />
Carina Enke 62.1 329 {{/code}}
330
Carina Enke 264.1 331 ===== How to mark an image as decorative =====
Katharina Schönefeld (Admin) 196.1 332
Katharina Schönefeld (Admin) 234.1 333 [[image:Texteditor-Bilder-dekorativ.png||data-xwiki-image-style="img-screen" data-xwiki-image-style-border="true" height="224" width="300"]]
334
Carina Enke 235.5 335
Carina Enke 264.1 336 **How to empty the alt attribute for images without relevant information in HTML**
Carina Enke 235.5 337
Katharina Schönefeld (Admin) 198.1 338 {{code}}
Carina Enke 235.4 339 <img src="..." alt=" " />
Katharina Schönefeld (Admin) 198.1 340 {{/code}}
Carina Enke 62.1 341
342 {{info}}
Carina Enke 264.1 343 The contrast should also be checked for images. The main subject in the image should stand out sufficiently from the background. Tips can be found at [[leserlich.info>>url:https://www.leserlich.info/kapitel/bilder.php||shape="rect"]].
Katharina Schönefeld (Admin) 203.1 344 {{/info}}
345
Carina Enke 264.1 346 {{panel title="Further information"}}
347 * Tips on how to write good alternative texts and image descriptions: [[Broschüre "Gut Fürs Image" (PDF)>>url:https://weiterbildung.dvbs-online.de/files/ibob-daten/Inhalt/Infothek/Brosch%C3%BCren/bf_Gut%20f%C3%BCrs%20Image%20-%20Praxisleitfaden%20zur%20Erstellung%20textbasierter%20Alternativen%20f%C3%BCr%20Grafiken.pdf||rel="nofollow" shape="rect" class="external-link"]]
Carina Enke 62.1 348 * [[How to write better alt-text descriptions for accessibility>>url:https://bighack.org/how-to-write-better-alt-text-descriptions-for-accessibility/||shape="rect"]]
Katharina Schönefeld (Admin) 203.1 349 * [[Five golden rules for compliant alt text>>url:https://abilitynet.org.uk/news-blogs/five-golden-rules-compliant-alt-text||shape="rect"]]
350 {{/panel}}
Carina Enke 62.1 351
Carina Enke 258.2 352
353
Carina Enke 264.1 354 === Optimizing images for smartphones and tablets ===
Katharina Schönefeld (Admin) 203.1 355
Carina Enke 264.1 356 For images to be displayed in full on small-screen devices and without users having to scroll horizontally, the maximum width in HTML should be limited to 100%. This ensures that the image is only displayed in the selected size until it is wider than the available space on the screen.
Katharina Schönefeld (Admin) 203.1 357
Carina Enke 264.1 358 HTML code for max-width
Katharina Schönefeld (Admin) 203.1 359
Katharina Schönefeld (Admin) 198.1 360 {{code language="html"}}
Carina Enke 235.4 361 <img src="..." style="max-width: 100%" />
Katharina Schönefeld (Admin) 203.1 362 {{/code}}
Carina Enke 186.1 363
Carina Enke 258.2 364
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Carina Enke 264.1 366 === Providing alternatives for videos and audio files ===
Katharina Schönefeld (Admin) 231.1 367
Carina Enke 264.1 368 When using media, make sure to always offer the info in an alternative format. In addition to image descriptions (alternative text) for images, think about pure audio content (e.g. podcasts) and video content with images and sound.
Katharina Schönefeld (Admin) 203.1 369
Carina Enke 264.1 370 * Provide alternative content or a transcript if you use audio files such as podcasts.
371 * Provide subtitles and sign language translation for video content.
372 * Integrate media from external platforms, such as YouTube or[[ Videocampus Sachsen>>url:https://videocampus.sachsen.de/||shape="rect"]]
Carina Enke 186.1 373
374 {{info}}
Carina Enke 264.1 375 On video platforms such as YouTube and Vimeo, subtitles are generated automatically. You can edit them if you need to.
Katharina Schönefeld (Admin) 203.1 376 {{/info}}
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Carina Enke 264.1 378 {{panel title="Further information"}}
Katharina Schönefeld (Admin) 203.1 379 [[Videocampus Sachsen: Erstellung von Untertiteln für Videos (TU Chemnitz)>>url:https://blog.hrz.tu-chemnitz.de/urzcommunity/2021/06/16/erstellung-von-untertiteln-fuer-videos/||shape="rect"]]
380 {{/panel}}
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Carina Enke 235.3 382
Katharina Schönefeld (Admin) 203.1 383
Carina Enke 264.1 384 == Colours & contrasts ==
Katharina Schönefeld (Admin) 203.1 385
Carina Enke 264.1 386 When selecting colours, make sure there is **sufficient contrast between the background and text colours.** Black on white generally offers the best **contrast ratio**, which should be at least** 4.5:1 **([[WCAG 2.1 - Contrast>>url:https://www.w3.org/TR/WCAG21/#contrast-minimum||shape="rect"]]).
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Katharina Schönefeld (Admin) 203.1 388 {{error}}
Carina Enke 264.1 389 Avoid challenging colour combinations such as red on green or black, as these can be difficult for some people to see. Bright colours and flashing elements should also be avoided.
Katharina Schönefeld (Admin) 203.1 390 {{/error}}
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Carina Enke 264.1 392 **Colour should never be used as the only means of highlighting information**. Instead, supplement information such as notices or error messages with a clearly recognisable icon and additional text. Avoid instructions or descriptions that refer only to a colour or other visual cues, e.g. ‘Click on the green button’.
Katharina Schönefeld (Admin) 203.1 393
Carina Enke 264.1 394 {{panel title="Further information"}}
395 * [[Contrast calculator from leserlich.info>>url:https://www.leserlich.info/werkzeuge/kontrastrechner/index.php||shape="rect"]]
396 * [[Choose your colours with color.review (EN)>>url:https://color.review/||shape="rect"]]
397 * [[Check your contrasts with the WCAG contrast checker (EN)>>url:https://contrastchecker.com/||shape="rect"]]
Katharina Schönefeld (Admin) 203.1 398 {{/panel}}
Carina Enke 62.1 399
Carina Enke 235.3 400
Carina Enke 264.1 401 == Useful tools ==
Katharina Schönefeld (Admin) 203.1 402
Carina Enke 264.1 403 * Check websites with [[WAVE Toolbar>>url:https://wave.webaim.org/||shape="rect"]].
404 ** [[WAVE für Google Chrome>>url:https://chrome.google.com/webstore/detail/wave-evaluation-tool/jbbplnpkjmmeebjpijfedlgcdilocofh||shape="rect"]] (browser extension)
405 ** [[WAVE für Firefox>>url:https://addons.mozilla.org/en-US/firefox/addon/wave-accessibility-tool/||shape="rect"]] (browser extension)
406 * Free open source screen reader for Windows: [[NVDA download>>url:https://www.nvaccess.org/download/||shape="rect"]]
407 * [[Checkliste: barrierefreie PDF-Dokumente>>url:https://www.einfach-fuer-alle.de/artikel/checkliste-barrierefreie-pdf/||shape="rect"]] from Einfach für alle