that's really interesting--thanks for those suggestions! I didn't realize automatic corrections would make such a difference, but it makes sense, since a typical garden photo has an array of not only colors but also variations in brightness across the leaves and blossoms--this could definitely throw off anything automatic! Good idea to find a specific local place and talk to them about it-- 'look, these are all photos of green things and things that bloom in a variety of different lights, brightness levels, and colors!'
well, I talked to online vendor #2 yesterday and they also are reprinting their large order for me. they said if I'm not happy with the second attempt we can talk about 'other options'. The 2nd large batch (from online vendor #1) is borderline in its quality-- overall better than the first small batch was, though not great -- I'm going to wait and see what their replacement order looks like before talking to them about the large order-- whether to try again with it or just leave it be.
I'll definitely keep local printers in mind for future orders...