Lights on RGB Strip are not working correctly

I want to control a RGB strip with an Arduino and NPN transistors. The problem is, that the blue LEDs only light up at an extremely low brightness. Also when the red LEDs are on, the green ones are shining at a much lower brightness, than normally.
Regardless witch pin I connect to which LEDs on the strip, the blue one is still always the one that's not working. The strip does not seem to be the problem, since I tested the setup with another strip, that's working correctly.
The same problems accours with a CH340G Arduino Nano and with an original Arduino Leonardo.
I'm using S8050 transistors.

int green_light_pin= 11;
int red_light_pin = 9;
int blue_light_pin = 10;
void setup() {
  pinMode(red_light_pin, OUTPUT);
  pinMode(green_light_pin, OUTPUT);
  pinMode(blue_light_pin, OUTPUT);
}
void loop() {
  RGB_color(120, 0, 0); // Red
  delay(1000);
  RGB_color(0, 255, 0); // Green
  delay(1000);
  RGB_color(0, 0, 255); // Blue
  delay(1000);
  RGB_color(255, 255, 255); // White
  delay(1000);
}
void RGB_color(int red_light_value, int green_light_value, int blue_light_value)
 {
  analogWrite(red_light_pin, red_light_value);
  analogWrite(green_light_pin, green_light_value);
  analogWrite(blue_light_pin, blue_light_value);
}

RRB_Test.ino (661 Bytes)

Hnm, you appear to have 12V RGB LED strip, which would typically have 3 LEDs in series with a current limit resistor.
You are only powering it with 9V. And from a very current limited 9V battery, typically rated for 500mA with a 15mA load.

Try with a better power source.

CrossRoads:
Hnm, you appear to have 12V RGB LED strip, which would typically have 3 LEDs in series with a current limit resistor.
You are only powering it with 9V. And from a very current limited 9V battery, typically rated for 500mA with a 15mA load.

Try with a better power source.

That was it, thanks! I didn't think that would have such a high impact, since the strip is rather short.
Thanks a lot for your help!