plantuml with black color vs monochrome

Question

Plantuml can use a mono mode to draw sequence diagram without colors as below:

skinparam monochrome true

But the color seems is monochrome so it's not so clear as a black color.The output figure looks like a grey color but not a black one.

Is it possible to use a black color mode rather use monochrome mode?

Answer 1

It actually a back color but not a grey. if you zoom in, you will find it's true.

Answer 2

Try specifying other skinparam options, which will turn off shading, make class backgrounds be transparent, etc.

skinparam monochrome true
skinparam backgroundColor transparent
skinparam classBackgroundColor transparent
skinparam style strictuml
class A {
  name : String
  getName() : String
}
B o-> A : contains

Compare to the result without these options:

skinparam monochrome true
class A {
  name : String
  getName() : String
}
B o-> A : contains