Is there an educational discount?
Yes, if you are a student and you can provide some proof of that, you can get a discount. For an even better discount, find two or more others who would like to buy a license. Email me for more information.
The plug-ins appear in the menu, but are grayed out
This means that the image mode of your current image is not supported. Change your image mode to RGB or CMYK with 8 bits per channel. Any other formats are not supported. If you really need another format, email me about it. But note that formats with more data, like 16 bit per channel will take about two times longer to process.
One of the most common problems is anti-aliasing in the artwork. Photoshop turns this on automatically, but anti-aliased artwork has a lot of grey pixels. And these cannot be processed by Flatten or MultiFill. MultiFill will not recognize pixels as white if they are not completely white. And Flatten does not recognize grey pixels as black.
So, try to use artwork without anti-aliasing. To remove it from the artwork, use the threshold function in Photoshop. Or change the image mode to grayscale, then bitmap, then back to grayscale and then RGB. But it's easier to use the threshold function. You have to experiment a bit to get the proper threshold value for your image.
MultiFill does not do anything
MultiFill searches for pixels to paint. Normally that means it will only paint 100% white pixels. You can change the color to paint with the top color-swatch. Right next to it is the threshold, this controls the sensitivity of recognizing pixels to paint. A zero value means it needs an exact match. Making it larger, will paint more colors. The newest version of MultiFill will give you a warning when no pixels to paint were found.