Hi Lew,
Yes the tannic acid solution does not make the pattern pop out as much, but from a conservation (museum) point of view, ferric chloride is not an acceptable method. Even with neutralization. With this process, we do not use water. I have also found a method to give a great golden sheen. I am still working on that one, but it is beautiful. 99% of curators would not let a conservator use ferric or nitric acid.
On another note, I have done extensive research on the different between wootz and pulad. It seems that the difference in the pattern is initally due to the fact that the indians take out the ingot while liquid and the solidification and cooling is very fast, which produces small dendrites. In the persian pulad process, they ingots solidify and cool slowly, thus producing large dendrites. From Verhoeven et al reserach, the cementite aligns along the impurities from the dendrite formation, thus big dendrites, coarser pattern vs faster cooling, smaller dendrites, finer pattern. However, final forging and trace and minor elements also plays a part.
Ann
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