Images very dark after OCR

First of all, thank you for this wonderful piece of software!

I have used the OCR option in some old newspapers and it worked really well, much better than I expected. However, the images in the resulting PDF file are much darker than the originals, to the point that some can hardly be read. I am attaching two images so that you can see before and after. In some cases it was even darker. Is there a way this can be tuned? Thanks!