Question in context with Adafruit 4-Digit 7-Segment Display with I2C Backpack

General
5

Thx for example and helpful hints: solved the point with the leading zeros as follow:

    // Get the current time in HHMM format
    the_time = Time.hour()*100+Time.minute();
    //Serial.println(the_time);
     
    // Display the time in 24 hour format
    if(TWENTYFOUR_HOUR==1) {
        matrix.print(the_time);
        
        if (Time.hour() == 0) {
             matrix.writeDigitNum(1, 0); // = first value = number of digit - in this case = second digit, starts with 0 to 4; second value = value to display
        } 
        if (Time.minute() <= 9) {
             matrix.writeDigitNum(3, 0); // = first value = number of digit - in this case = third digit, starts with 0 to 4; second value = value to display
        }

Yes, the brightness is set by this command:
matrix.setBrightness(brightness); // max brightness: 15
but also with brightness = 0 the display is on and shines a bit bright.

I look at the strings again.