the shield is basically a sponge. its not based on damage at all.
its based on ink covered per shot.
a fully charged e-liter shots packs a lot of ink in just one shot, which is why it only takes two.
an aerospray which covers very small amounts per shot takes 15+ shots to take it out.
this turf-based tug of war balances out any DPS differences between weapons which is smart of the devs.
the 1000 HP only applies to non-ink attacks: the Killer Wail.
No, the shield is definitely HP based; I know from testing that Damage Up will allow you to break it in fewer shots. The tricky thing is that it seems to respond differently to different weapons.
That's interesting. I tried this with Tentatek once and it took me 28 shots to burst the shield. 28 x 36 dmg = 1,008, so I figured the shield had 1,000 HP. But I think this calculation applies only to shooter weapons. Chargers and bombs seem to be able to splat the shield quicker and Killer Wail or Inkstrike are instant splats.
I noticed the 1,000 HP thing about shooters too (including the Splatling). It made me wonder if it's actually just 500 HP (like the large dummies in the testing range) with a damage multiplier applied depending on the weapon--0.5 for shooters, 1.0 for rollers, 1.5 for chargers, etc.
The Slosher is just plain weird; I can tell by the sound that the ink toss is somehow hitting the shield multiple times, and my results with it haven't been very consistent.
Also, I would just like to point out that the Killer Wail and Inkstrike aren't exactly insta-splats. They deal damage very quickly, but it does take a bit of time for the damage to add up to enough to burst the shield. (Even an Inkling can suffer non-lethal damage from a Killer Wail if caught in it for a short enough time.)