Join Anne-Marie Concepción for an in-depth discussion in this video Adding alt tags to images in InDesign, part of InDesign CS5.5 to EPUB, Kindle, and iPad.
One element of EPUBs that doesn't get a lot of attention, but really should, is the issue of Alt tags, meaning alternate text. And that's because, like metadata, it is something that is saved with the file that's not immediately visible. But it's very useful for people who are doing searches on eBook databases, and of course it's extremely important for people who are visually impaired. So if you are trying to make an accessible EPUB you really want to add descriptive Alt tags to your images so that as the eReader is reading aloud the story, when it comes to the image it won't say the name of the image, which is the default Alt tag that InDesign adds. Instead it'll read the description of the image that you can add yourself, or that maybe the photographer has added in Photoshop, or Bridge, or Lightroom.
In addition to that, any kind of elements that you convert to an image, like I described in a previous video, such as InDesign artwork, you could also add Alt tags to that as well. Let's take a look at this document and see where we might decide to add our own custom Alt tags, and how we would do that. It's a really simple three-page document, and I have here a custom headline. Now when I exported this to EPUB it opens up with his big honking blue headline which is trying to pick up the overridden paragraph style of that type. But of course it can't pick up that typeface, and normally you don't want to embed typefaces because often it will fail validation. Plus this might be an unembeddable typeface.
But let's say for some reason I really wanted to use this typeface in my EPUB. Well, then the only solution would be to convert this into an image, and I talked about how to do that in the previous video, so I am just going to jump right to it. I will select this image, go to Object, down to Object Export Options. And I am going to say when this is export to EPUB or HTML I want it to be rasterized. And I'd like it to resize according to the width of the page, JPEG is perfectly fine. And the Resolution, I think I'll keep at 300.
Notice there's another tab here called Alt Text. So a good idea if you're ever rasterizing any text elements, as we are doing here, is to add your own custom Alt Text that is the same text as what you are rasterizing. If I were smart I would have copied and pasted, but I am not so, San Francisco. Now what will happen when the e-reader reads this aloud, it will come to this element and it will say, An Illustrated History of San Francisco Image.
So you might want to add something like Title. So if you're rasterizing some sort of text, you might want to add a little descriptor before it. Now you don't have to purchase anything special, by the way, to test this out. If you have an iPad, you can turn on a new feature called VoiceOver in iBooks that will automatically read anything that you point to, and if you tap on an image in an EPUB it will read the Alt Text. So that one is done, and then we can do the same thing for these images. If we want, we can select an image and go to Object>Object Export Options.
This will already be rasterized, so we don't have to come to this tab. But here we can enter some Alt Text. We can type in something ourselves. We don't have to type in the caption, because the e-reader would read aloud the caption assuming that we are going to export the caption as well. But look at this thing, From Structure, what's that about? From Structure refers to the XML structure. If we were adding Alt tags to this image in an XML workflow it would pull it from there. Or you could choose it from the embedded metadata that's already in the image, such as its title, or description, or headline, or from some other field.
Now that would be really cool if we could get this to automatically populate, and actually it's very easy to do. I will close out of here, and in the Links panel -- the Links panel shows you the links to all of the placed images, or PDFs, or whatever. You select an image, whether it is floating or anchored in the text flow as this one is, and it will become highlighted in the Links panel. And then you can right-click and say Reveal in Bridge. And when you do that, that image becomes selected in Adobe Bridge. It might take a second for it to start up, because mine was already running.
Now we have a number of videos here at lynda.com that talk about Bridge. But the cool thing for us is that you can select any image and here in the Right panel under Metadata you can enter some metadata. So like under IPTC Core, under Description, we will type in, An old time postcard showing Market Street. Let's just leave it like that. And you can enter anything else that you'd like. Your headline, and so on. And in a typical workflow, the photographer, or an assistant, or the lucky intern who can apply all the metadata and keywords to all of these, and you can do multiple images at a time.
Let's actually do a few. So we will take this one: yes, we want to apply that. This is San Francisco area before it was settled by Europeans. San Francisco area before it was settled by Europeans>Apply. And then there is Castro Street; it already has some keywords I see here, because our friend Nigel is the one who took the picture and he is very careful about adding keywords and identifiers. He is great. But I will just write Castro Street sign in San Francisco, and apply that one.
So when we come back to InDesign these three images have all been updated. So I am going to Shift+Click all of them and say Update the links. And now for this image we can go back to Object Export Options, and say From Description, and it automatically populates it. Let's do that to the other two images. I am sure that once more people become aware of this very cool feature that some wonderful scripter will come up with a script that will automatically populate all of these images with whatever XMP information you want it to. In the meantime we have to do each one individually. There you go! So remember you can choose an XMP bit of data that is built into the image, or you can choose custom and type out your own.
Now we will Save this and export it to EPUB. We will do version 2, and there is nothing special that you need to do in EPUB Export Options to retain those. Click OK, and now we have our beautiful illustration, but if somebody is doing a search in this EPUB and they say, gee, do I have anything that's says, an illustrated history? This would be a hit because it would match the Alt tag. And then let's actually preview in TextWrangler and we can look at the very first block. Here's the block that we had rasterized.
It turned into a JPEG. Now if we hadn't added our own Alt tag, Title: An Illustrated History of San Francisco, the Alt tag would have been 505.jpg image. So this is much better for anybody who is actually reading it or searching it. And here's one of the other images: Market Street San Fran, and the Alt tag: an Old time postcard showing Market Street. So you can see how easy it is with InDesign CS5.5 to enhance your EPUBs with descriptive text for anything that's going to be rasterized after the EPUB process.
- Understanding ebooks and ebook publishing
- Examining the EPUB format
- Creating customized navigational TOCs
- Using layout order, the Articles panel, and XML tags to manage content flow
- Formatting with paragraph and character styles
- Creating a cover image
- Optimizing images
- Exporting InDesign content to an EPUB
- Including drop caps, pull quotes, and text wraps
- Acquiring an ISBN for ebooks
- Converting an EPUB to Kindle, iBookstore, and Nook formats
- Distributing ebooks with resellers and aggregators