How to use MultiFill
The MultiFill plug-in is like the paint-bucket in Photoshop, but it fills all the white area's in the image, each with a different color. The colors are picked from a Photoshop palette, but only colors that are not close to white or black are used.
The MultiFill dialog
The MultiFill dialog has a number of options. Each of these options are described in this section.
Paint White and Gray Pixels
When this option is turned on, MultiFill will all pixels that are gray or white, In an image with only black line-art on a white background, the anti-aliasing pixels are in shades of gray. So with this option you can use MultiFill with images that have anti-aliasing. Though in some cases you will get better results if you use the threshold function.
Basically you always want to use 100% white here. But in some cases you may want to paint over a different color. In that case use this option.
This applies to the MultiFilled color and controls how accurately a color much match the multi-filled color. A value of 0 means that only pixels that have the exact same RGB values will be painted. The value of the tolerance is how much each of the RGB components may differ from the painted color. Where the RGB components are measured with values from 0 to 255.
Choose your favorite palette here. Paint colors are taken from this palette. You can also create your own palettes in Photoshop. If they are in the Palettes folder, MultiFill can find them.
Turn this option to lump together small areas. The value is the maximum size for joined areas. When a small area is joined, it will get the same color as the closest by larger area.
Turn this option on to flag small areas. The flagged areas will get the color specified in the color swatch. The value is the maximum size for flagged areas.
Measure size by
This applies to Join Areas and Flag Areas and controls how the size of an area is computed. Pixel Count or area is the total number of pixels in an area. With the height & width option the height and width of each area is computed. And if both of those not larger than the maximum value, the area is flagged or joined.
MultiFill and Photoshop Actions
MultiFill supports running as an action. All the parameters specified in the dialog can be recorded in a Photoshop action. Just create a new action, start recording, open MultiFill and choose the settings you want. After MultiFill completes, stop recording. Now you can apply the action to any file. Of course you can create multiple actions with different settings.