Hi Dillon,
Whenever you want to exclude certain targets from being heard over the headphones, you have to blacken out the area of the screen where their(induction,conduction) point is plotted. In discrimination mode, you can blacken out any part of the screen you want. But in iron mask mode, you can only add or remove "strips" of blackened area from the screen. At Iron Mask -16, your screen has no blackened area and is accepting all metals. At Iron Mask -15, notice that a uniformly shaped thin black strip of blackened out area has been added to the far lefthand side of the screen. As you increase the iron mask value from -15 to -14 to -10 to 0, blackened out strips are added one by one until you have half of the screen totally blackened out at the maximum iron mask value of zero. So the difference between iron mask mode and discrimination mode is the way you are allowed to add blackened out area to the screen. In iron mask mode, you are restricted to adding the uniform strips. In discrimination mode, you may blacken out a point, or any non-uniform or uniform shape you wish. In iron mask mode, you are able to quickly add black strips that suppress iron signals that typically fall in the far left and over to the middle of the screen. Since this area of the screen (far left to middle) is where most iron hits register, the iron mask mode can be used as a convenient way to add more and more discrimination until you stop being bothered so much by iron targets. But blackening areas in the far left to middle part of the screen may not take care of aluminum pulltab problems. In this case, you can go to discrimination mode and learn out the aluminum hits if you want. Good LUck
Mike
