Thanks jjphoto. Are APO lenses marked as such?
Not always, but often they are. Rodenstock and Schneider explicitly mark them as APO in the product names.
And yes, with a bit of looking around highend enlarger lenses can be rather cheap. I paid 80 euros for my APO-Rodagon 50mm. At that kind of prices there is very little to fuss over. (especially not compared to the price of good camera lenses....)