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• The sliders in Filter Factory are referred to as controls, abbreviated "ctl," followed by a number representing the particular slider. They are numbered 0 through 7, rather than 1 though 8. Ignore the "Map" labels. They don't mean anything for this tutorial.

  Operators (+, -, /, *): For operations, we simply use +, -, / and * (addition, subtraction, division and multiplication, respectively). So, 3*3=9.
• Sliders (ctl(0) though ctl(7)): To specify which slider you want to have control over a particular aspect of your equation, signify the control as ctl(0) through ctl(7). That's eight controls, numbered 0 though 7. So, if ctl(0) is set to 3 and ctl(1) is set to 3, then ctl(0)*ctl(1)=9.
• Pixel Coordinates (x, y, X, Y): We're also going to be using x, y, X and Y. These represent horizontal and vertical pixel coordinates. Lowercase x and y represent the current position of each individual pixel. Uppercase X and Y represent the edges of the image. So, if you want to move all of the pixels in your red channel, for example, you could write "x-3,y-3" in the R field. This will shift your red channel down and over by three pixels. Or you could write "x-ctl(0),y-ctl(1)," which would shift your red channel down and over a number of pixels equal to the current value determined by the position of the first and second sliders.
• Function (src): Now, we also have to use a couple of functions. Literally just a couple in the beginning. The first one is src. This src function is just used to tell Filter Factory where it's supposed to pull its pixel information from, namely your image. So, instead of simply writing "x-ctl(0),y-ctl(1)," you write "src(x-ctl(0),y-ctl(1)). It's basically just a formality, but you have to do it to get this to work properly. One other thing you have to do is to specify a channel in your src expression. This is simply a matter of placing a number 0 though 3 at the end of the expression so that it looks like "src(x-ctl(0),y-ctl(1),1)."
• Function (rnd): Finally, for this tutorial, we will introduce the random function. This is a great one for generating noise effects. Basically, all you have to do is write something like rnd(1,30) to generate a random number between 1 and 30. Of course, you can use controls instead of absolute numbers. In other words, something like src(x-rnd(ctl(0),ctl(1)),y-rnd(ctl(2),ctl(3)),1), which will offset your pixels by a random number between the values set by your sliders. Quite handy for bringing in gradual noise.

So these are all the things you have to know to get started. So let's get started.

Example 1: hue shifting
Just to start off, so you can see that this thing actually works, go into the Filter Factory in Premiere and set the R, G and B text fields to ctl(0), ctl(1) and ctl(2), respectively. Then play around with the first three sliders. Notice something? You're just getting solid colors. But when you move the sliders back and forth, the color changes depending upon the value for each channel.

Neat, but useless. So let's add in some practicality. This time we're going to try a hue shift. All we have to do for this is is take the default value of each cannel and add or subtract some slider values. So the red channel, for example, will read "r+(ctl(0)-ctl(1))."

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