DjVu2PDF 4+

This app does exactly what it claims to but it will take a long time to convert djvu documents, and the resulting pdf file size can be enormous. But you can get it to convert fast with better text if you choose the 'Black & White' option!

I first tried using this app with a 32Mb djvu on my 2012 i7 Mac mini with 16Gb RAM: it took over 5 minutes for the conversion, and the resulting file was over one gigabyte! When choosing a lossy conversion you're provided with a slider scale from 0-150, whatever that means. I did a second conversion of the same file with lossy=70: it took around the same time to create the file, which was now 'only' 932Mb. Third attempt was a lossy setting of 30: resulting file was 550Mb and of acceptable quality (almost identical to lossless conversion), which was better but still a big file and a long conversion.

I then switched the file to 'Black & White' (thankfully, my source was a book with b&w photos in it) and the resulting conversion (lossy, 30) took less than a minute, was only 64Mb, and the black text looked much better (the background was no longer dingy and yellowish from the original scan). FANTASTIC!

If you have lots of djvu files this app may be frustrating and you may want to pick a commercial app that does batch conversions. But for the occasional djvu (especially if the source doesn't have color photos) this app is great.

Although it needs to have better menu keys to show you where to find where to press, once you press the right button, the software does a perfect job of creating a lossless copy of my djvu in a pdf version of which I rather read on adobe. I recommend people use this if they need to convert their djvu to pdf.

I have tested the app on Mac OS 10.9 and it works well. The output pdf files are much larger than the input djvu files if you use the `lossless’ option.
You can try to optimize the size of the files using the related setting of Adobe Acrobat.