A suppressor value of 1 completely removes the effect. Any suppressor value over one will be a negative and cause image 4.
You should preview the RadialGradientExponential and Suppress effect to see what’s happening. The more white, the more intense the effect
Previewing suppressor with a value of 0.5, 0.7, 0.8, and 1, in that order.
I’m not completely clear on what you’re trying to do, but if you’re trying to decrease the effect, you can use a power node prior to the center suppressor effect.
A value of 1 is normal, a value of less than 1 is more intense, and a value higher than one is less intense.