I add a $50 digital editing fee to my day rates. I also do some graphic work for one client and charge him $50/hour, usually about 8-10 hours of easy work. It sounds like the photos you might be working with could be a tough call, if they are out of focus and they expect that re-touching will help that, they have to understand that it won't. It could also make you some easy money if they don't mind paying $50-80/hour for 200 images. The other side is that you just tell them it's $500 to do the retouching. You may be able to fly through them if they don't need much work, on the other hand if it takes you 3 days to get them all done........