Dragon Age uses tints applied to base models of armour and weapons in order to create impression various 'tiers' of these items are made out of different materials. However by default these tints are very strong, to the point where items may start to look as if made out of coloured plastic. As side-effect, armour pieces of different tiers when worn together can appear mismatched.
This modification changes strength of most of the tints. The basic tint colour is nearly removed, and the original tint is reduced to a distinctive sheen given to each material. The only exceptions are tier 7 materials -- drakeskin and dragonbone. As these components are supposed to be (at least in theory) rare and difficult to obtain, the tints for these materials were left at their original strength, to make such items stand out. The default colours were however tweaked, to match the appearance of creatures they're supposed to come from -- drakes/dragons for drakescale and high dragons for dragonbone.
unzip the archive to folder "../Bioware/DragonAge/packages/core/override" which is typically located in "My Documents" folder.
delete folders "tints-leather" and "tints-metal" from folder "../Bioware/DragonAge/packages/core/override"