Spec sheets quote the press: actuation force, bottom-out force, maybe a tactile peak. But a keystroke is a round trip, and the way back up shapes the feel just as much.
Why the lines don't match
Friction always works against the motion. Pressing, it adds to the spring; releasing, it subtracts. So the release curve sits a few grams below the press curve. That gap is called hysteresis.
A small gap (3–5 gf) feels snappy: the key returns with nearly the same force you pressed it with. A large gap feels damped, sometimes mushy.
What the numbers here show
- Linears have the smallest gap, around 5 gf.
- Tactiles add a smaller, earlier bump on the way up.
- Clickies have the biggest gap, because the click mechanism has to reset.
Lubrication narrows the gap more than it changes the press curve, which is why "lubed vs. unlubed" is easier to feel on the upstroke.