you can do it like that, to turn it one one second and off 4 seconds.

1. void setup() {
2.   size(600,400);
3.   smooth();
4.   background(255);
5. }
6. void draw() {
7.   background(255);
8.  fill(0);
9.  if(millis() % 5000 <1000)fill(255,0,0);
10.  ellipse(width/2,height/2,100,100);
11. }

i dont understand the second part though.
what do you mean by "while still having the loop run a second time and keep the LED off for 5 seconds." ?

Thanks for the replies.

Cedrick, the loop I have runs for 5 seconds and changes the LEDVal integer.
Each time the loop runs it checks what the LEDVal is, and reacts appropriately. The second time the loop runs, LEDVal will have changed to '0' it will do something different as seen in the last "else if".

I've not seen coding in processing using the method you've shown. How would I take your snippet of code and make implement it into mine?

I've tried to do implement the code from 'wmacfarl' but with little success. I might be making a noobish mistake though... 

1. if (amber == true) {
     
     while (millis() >= time + 5000)
      {
         startLoopTime = millis();
         // turn LED on/off:   
         LEDVal = 1 - LEDVal;
         if(LEDVal == 1) {
           
                   if (millis() < startLoopTime+1000){
                     //turn LED on
                    arduino.digitalWrite(redledPin, arduino.HIGH);
                    }
                    else {
                   //turn LED off
                   arduino.digitalWrite(redledPin, arduino.LOW);
                   }
          }
         
          else if(LEDVal == 0) {
          arduino.digitalWrite(redledPin, arduino.LOW);
         
          }
        
           time = millis(); //record current time
          
         }

Can anyone help?

Don't change the if to a while...
Use draw() as a loop of its own (it is called regularly by Processing).