The best etchant we've found is the standard Ammonium hydroxide/water/peroxide mixture. I would be concerned that you don't ALWAYS see demarcations due to the board being pulled from the tank. You should be able to see not only the grain structure but clearly see multiple plating strikes, and of course a sharp interface between the plated copper, electroless copper and copper foil. If you're not seeing all this, you can easily miss defects such as post separation and foil cracking. Here are some tips on using the Etchant. Note that different types of copper chemistries may etch a bit differently. If you are only working with your own boards, this shouldn't be a problem. 1)The ammonium hydroxide should be 28% reagent grade. 2)distilled or DI water is not necessary. Filtered water works best for us. 3)use 3% hydrogen peroxide 4)make sure the peroxide comes in a dark bottle, and keep it in a dark, cold location. We actually go to the local pharmacy and buy it there. It comes in a dark brown bottle (light degrades it) and we keep it in the refrigerator. 5)Mix the NH4OH/DI water/Peroxide in a 5:5:2 ratio 6)gently swab the microsection using a cotton ball that has been soaked in the etchant for 2 to 6 seconds (depending on the copper) 7)rinse the sample immediately with tap water and clean with alcohol before drying. We have a premixed bottle filled with 50% NH4OH and 50% Water. When its time to etch samples, we mix 10 parts of this mixture with 2 parts of the 3% hydrogen peroxide. Its important to mix the etchant fresh each time you need it for consistency. We went to this method due to problems you mention below. IF you have any questions, call me. Regards, Paul Terranova DIGITAL Analytical and Environmental Test Services Lab 508-467-3109 [log in to unmask]