It's got lots of color (which is lost on an ebook reader) and several embedded fonts (of they type I think of as "exotic" 'cos I'm from the USA and if it isn't done with the roman alphabet, it's an "exotic" font). There's something like Arabic involved, and that can slow down the reader.
It's a very complex layout for PDFs, and it's not surprising it takes a while to render. I've added tags, changed the metadata, and tried some optimization settings; I'm not sure if those changes will do anything helpful, but you can try it.
|