These notes are Inkscape-centric.

1.The PNG files were exported from and reflect the colors seen in Inkscape.
The Adobe plugin for MS Internet explorer and the native SVG support in
Firefox seem to implement filters differently from Inkscape. We can only hope 
that Inkscape is doing it correctly and the browsers are deficient.

2. The filters were designed for a specific purpose. They provide simple 
low relief 3-D effects while also suggesting ferreous metal patination. 

3. The 3-D effects are through a combination of embossing via diffuse lighting filters
and cast shadows using the offset and gaussian blur filters. Depending on what
you are doing, the cast shadow may get in the way. If so, duplicate and rename 
the filter, locate the blur and offset filters near the bottom and set their values to 
zeroes. If you are real adventurous, delete them entirely.

4. The object that the filter is applied to is treated as a height map. White pixels are
are "highest" and darker pixels are lower. I you need both embossed and etched 
features make the background medium gray and include white and black features.

5. Also, note the "USAGE EXAMPLE" for how the 3-D is affected by whether you 
group paths together before or after applying the filters.

6. The roughness of the SCALY RUST filter can be controlled by adjusting the 
lightness of a path that the filter is applied to using the HSL color control.

7. The roughness is minimized around a lightness value of 75 (hue and 
saturation are zero). Moving either lighter or darker from there increases the
roughness (taking into account note 4 above).

7. As with all artwork, the apparant color (hue and value) of an object is affected
by the background. These filters were developed over a white background.
The colors look reasonable down to a medium gray backgroud. When viewed 
against black they seem a washed out. I found the process of adjusting the colors
In the filter to be tedious and confusing. It might be easier to overlay a 
semi-transparent path over an object to tweak colors for your application.