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<p>[QUOTE=&quot;Insider, post: 2916970, member: 24314&quot;]<span style="color: rgb(179, 0, 179)">halfcent1793, posted:&nbsp; &quot;Dip silver coins if you must, but realize the <b><i>luster will diminish <span style="color: rgb(255, 0, 0)">every time you do it</span>,...&quot;</i></b></span> </p><p><br /></p><p><img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie11" alt=":rolleyes:" unselectable="on" unselectable="on" />&nbsp; The first time I heard this <b><i><span style="color: rgb(255, 0, 0)">nonsense</span></i></b> was from the mouth of a Commemorative coin expert who was a guest speaker at a grading seminar in the 1980&#039;s.&nbsp; His contention was that if you put a light meter on a silver coin and took a reading and then dipped it, the reflection of its luster would diminish and read lower on the instrument!&nbsp; <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie46" alt=":facepalm:" unselectable="on" unselectable="on" /> As soon as he left the class, our very knowledgeable <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie26" alt=":bookworm:" unselectable="on" unselectable="on" /> professional instructor <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie33" alt=":cigar:" unselectable="on" unselectable="on" /> informed the class to forget what they just heard <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie12" alt="o_O" unselectable="on" unselectable="on" /> as it was <span style="color: rgb(255, 0, 0)">absolute, uninformed, nonsense!</span>&nbsp; Next, he praised the expertise of his invited guest and surmised that a cloud must have blocked some of the sunlight during the expert&#039;s second reading. <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie14" alt=":angelic:" unselectable="on" unselectable="on" /></p><p><br /></p><p>The next week, the instructor explained the difference between dipping coins by <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie30" alt=":bucktooth:" unselectable="on" unselectable="on" /> amateurs and PROPER dipping.&nbsp; The class did some tests.&nbsp; Bottom line:&nbsp; If a coin is dipped properly, no one can tell after one dip. <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie57" alt=":jawdrop:" unselectable="on" unselectable="on" /> No one can tell after two dips. <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie57" alt=":jawdrop:" unselectable="on" unselectable="on" /> No one could tell after three dips. <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie57" alt=":jawdrop:" unselectable="on" unselectable="on" /> Do you see where this <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie103" alt=":yack:" unselectable="on" unselectable="on" /><img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie103" alt=":yack:" unselectable="on" unselectable="on" /><img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie103" alt=":yack:" unselectable="on" unselectable="on" /> is going? <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie104" alt=":yawn:" unselectable="on" unselectable="on" /> Sometime between many acid dips and the thousandth - <span style="color: rgb(255, 0, 0)">when the coin and your fingers dissolve <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie40" alt=":dead:" unselectable="on" unselectable="on" /></span>, its luster WILL BE diminished <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie10" alt=":oops:" unselectable="on" unselectable="on" />.&nbsp; How much and when depends on a number of variables.&nbsp; For example, you can take a gem DCAM Proof and leave it in a bowl of &quot;Tarnex&quot; for awhile and its luster will be diminished with <b>one</b> dip BUT that&#039;s not considered proper dipping.&nbsp; <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie52" alt=":hilarious:" unselectable="on" unselectable="on" /><img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie52" alt=":hilarious:" unselectable="on" unselectable="on" /><img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie52" alt=":hilarious:" unselectable="on" unselectable="on" /><img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie52" alt=":hilarious:" unselectable="on" unselectable="on" /><img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie3" alt=":(" unselectable="on" unselectable="on" /></p><p><br /></p><p><span style="color: rgb(179, 0, 179)">[USER=86853]@halfcent1793[/USER] <span style="color: #ff0000">properly cautions</span>: &quot;<b><i>NEVER use any acid dip on copper coins. </i></b>It micropits the surface very quickly. The acid in the dip is the major problem. It dissolves native copper as well as toned copper patina.&quot;</span></p><p><br /></p><p><span style="color: rgb(102, 0, 0)">mrjason71, posted:&nbsp; &quot;Gotcha. Like I said I would think it would be pretty easy to test. Could dip a red unc copper--one you know has no micro pitting. Do you have micro pitting after?&quot;</span></p><p><br /></p><p><img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie15" alt=":arghh:" unselectable="on" unselectable="on" />&nbsp; How much power do you wish to use?&nbsp; See the point? Numismatists do not work at the atomic level of a coin&#039;s surface. I applaud your curiosity, <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie59" alt=":joyful:" unselectable="on" unselectable="on" /> but please don&#039;t complicate the thread as you&#039;ll drive yourself and others nuts. Yes, crank that Electron Microscope up, take before and after scans of the coin&#039;s surface and you&#039;ll prove @halfcents is correct. Then, we can determine how many dozen dips it takes to pit the surface enough to change the luster to a professional grader&#039;s eyes!&nbsp; <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie8" alt=":D" unselectable="on" unselectable="on" />&nbsp; Let&#039;s see, that test could be done at a cost of $$$ and take most of the day preparing the sample after each dip. <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie8" alt=":D" unselectable="on" unselectable="on" /></p><p><br /></p><p>BTW, copper coins are being restored to &quot;market acceptable <span style="color: #b30000">red</span>&quot; and slabbed.&nbsp; It has been going on for <b>decades</b>. <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie57" alt=":jawdrop:" unselectable="on" unselectable="on" /><img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie46" alt=":facepalm:" unselectable="on" unselectable="on" /> I believe that folks here are just arguing about the &quot;numbers.&quot; <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie50" alt=":happy:" unselectable="on" unselectable="on" />[/QUOTE]</p><p><br /></p>

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