[PIC] I am using 36x8 led matrix display .brightness of led is low how increase brightness

char array[36],p,j,s,i,still;
void clock(){RB7=0;RB6=1;RB6=0;}
void data(){RB7=1;RB6=1;RB7=0;}


void scroll(char a,char b,char c,char d,char e,char f,char g)            //display function //
{  
    short int count=7;
    while(count>0)
    {     
        
        array[0]=~a;
        a=b;b=c;c=d;d=e;e=f;f=g;g=255;        
         data();
      
            for(i=0;i<36;i++)
            {
                p=1;
                for(j=0;j<35;j++)
                {                      
                    PORTD=~(array[i]&(p));delay_us(55);p<<=1;
                    
                }                
                 clock();           
                 }
                        
        for(i=35;i>0;i--)
        {
            array[i]=array[i-1];
            
        }
        count--;   
    }  
}