I'll chance my arm! I can't comment on the numbers you've given since I'm not sure what they relate to. On the other hand, the 7800 uses the same k3 inkset as the 3800 - and people are making great digital negatives with that for a whole range of processes, so it should be fine. You may want to double check on the photo vs matte black choice for digital negatives though. I've heard the k3 photo black is a weak UV blocker. The 3800 has both carts installed at once which is great (since the matte black is a good UV blocker), and if you need to switch between the two it's a breeze. With the 7800 you have to physically switch the cartridges which is time consuming, ink consuming, and therefore expensive. Unless you dedicate such a big printer to digital negatives (not sure why you'd want to do that), you could find yourself switching back and forth quite a bit. There's been the odd post in the past about the Z3100 (I think I asked about it once!) - from what I can remember I think there was a positive response, but you may want to double check. The starting point with any inkjet printer, for any process, using any system (colorized neg., composite black etc.) is whether or not it can produce a dense enough portion of the negative to get paper white (or very near paper white if you still want detail in the uppermost highlights of your image) with your chosen process? If so, you've got a starting point...