PDF to tiff ImageMagick problem

I'm trying to convert pdfs to tiff images for following OCR. I use "-density 300x300 -depth 8" as parameters. The first problem is that from 500 KB pdf file i get 72 MB tiff file. The second problem is bad quality of resulting image causing OCR failing. Here you can see it yourself. Adobe acrobat reader generated (printed) tiff image:

ImageMaggick tiff image:

The difference is huge. How can i get as good as Adobe generated image using ImageMaggick? Not tiff neccesary, other formats also will be good.

UPD: i've found 'antialias' option. Now it's much more better. But still OCR result not so accurate as for Adobe version.