Dust & Scratches working replica

Well… while it's certainly working, the values needed to get the same result than in PS are different.

I'd like some of you guys to help me to figure out 2 things:

1) What's the difference with Photoshop's filter? :

For example: In FF, I need to set up the filter size to 512px, to get the same "Median" radius that In Photoshop's "Dust & Scratches" filter. It's like the pixel size is not 1px in FF, while in PS 1px = 1px.

That's not big deal, if that value (512) that I set up stays that way regardless of the image loaded (don't know), but I am still wondering why is that.

But the threshold… it's a different story. I have to use a value of 7px in FF, to get the same result that in Photoshop using 17px.

2) Is there a way to threshold an image in RGB mode, instead of b&w?
If you take a look to the file I'm posting, 75% of the mess in the workspace comes from splitting the RGB into separated channels to be threshold-ed and merging them back.

But, hey! it's working anyway Dust & Scratches behavior in FF

dustNscratches.ffxml

Thanks ThreeDee!!

That was awesome. I didn't know I can use other than a solid color for the high and low values in the threshold. That just put the limits of my understanding about FilterForger way further away.

Do you have an idea how much it could take to make that filter in SDK? (a filter twice this small)