As a translator, I employ a proofer who corrects all my translations. She fixes my typos, streamlines my sentences and in general acts more like an editor than a proofreader (I, on my turn, try to pay her accordingly). Her contribution helps making sure that my clients receive a translation of the same quality or better than those commissioned and published by traditional publishers.
Of course, professional proofreading has a cost. Good work deserves good pay, and you would be surprised by how much a translator can and should invest in proofreading. This cost cannot be avoided by any serious professional, because – as every writers knows – you can’t proof your own work and expect perfection. Your eyes will see perfectly formed words instead of misspelled ones. Your brain will fill the gaps where missing words should be. It happens all the time. This is why you need another, clever pair of eyes.
Also, sometimes, a good proofreader can save a translator’s life by pointing out a solution to the problem they had been struggling with. Maybe the translator didn’t know how to translate a certain word or expression, and the proofreader did. It rarely happened to me, but it did happen. It’s like trying to tear down a wall with your bare hands, and then someone comes and points at the door that has been there all along. It’s liberating, in a way.
This is why translations are expensive: most often, they receive the contribution of more than one person. Beware of translator who don’t have their own proofers: they are more likely to leave typos and mistakes in their work, simply because their own eyes cannot catch all of them (again, this is something every writer knows). Cheaper rates may come from the fact that the translator is willing to cut the costs, but in this case, removing the cost of proofreading will reduce quality.
A translator with their own proofreader also provides you with the benefits of a partnership, which acts as a force multiplier: just like a writer and their personal translator, a translator and their personal proofreader form a work relationship that matures over time, leading to every project being better than the one who had come before. If you ever worked with a partner, you know how deep that bond gets, to the point that you can understand each other without talking and you end up producing great results. This is what happens when a good translator and a good proofreader work together. I know that my proofer is good, so I take all her suggestions into consideration. And the authors I work with greatly benefit from that.