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<p>[QUOTE=&quot;ToddB67, post: 3321053, member: 18134&quot;]Thanks everyone for replies to this thread !</p><p>GDJMSP&#039;s was especially informative. <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie1" alt=":)" unselectable="on" unselectable="on" /></p><p><br /></p><p>Before posting this thread I had collected some information during my efforts to obtain answers to:</p><p><br /></p><p>#1..The average microscopic size range for Length, Width and Depth of Hairlines and Scratches found on coins.</p><p>#2..The magnification power required to see these imperfections.</p><p><br /></p><p>So today I decided to publish what I collected FYI (below).</p><p><br /></p><p><a href="https://www.numismaticnews.net/article/scratches-vary-in-severity-on-coins" target="_blank" class="externalLink ProxyLink" data-proxy-href="https://www.numismaticnews.net/article/scratches-vary-in-severity-on-coins" rel="nofollow">https://www.numismaticnews.net/article/scratches-vary-in-severity-on-coins</a> <font size="6"><span style="color: rgb(255, 77, 77)">←</span></font> According to the 6th&nbsp; paragraph down on the 1st&nbsp; page of this link, the author says &quot;When does a hairline become a scratch? I believe it happens as soon as the mark becomes slightly wider or deeper – perhaps the thickness of the finest blonde human hair you could ever imagine.&quot;</p><p>So, according to that statement in quotes, which I interpret as defining scratches, and concomitant with the diameter range of Flaxen hair in the following link below, I have deduced the diameter and theoretically the width&nbsp; at a Min.- Max. level !</p><p><br /></p><p>See the following quote below that appears at the bottom of the chart in the The Physics Factsbook link below, that I converted to be from&nbsp; 0.0007&quot; (seven-ten-thousandths) to 0.002&quot; (two thousandsths) inch in my <span style="color: rgb(255, 0, 0)"><u>Legend</u></span> below. Hairlines would then be even smaller, perhaps down into the micrometer (millionths of a meter) size !</p><p><br /></p><p>&quot;Flaxen hair is the finest, from 1/1500 to 1/500 of an inch in diameter … and black hair is the coarsest, from 1/450 to 1/140 of an inch.&quot;&nbsp; <a href="https://hypertextbook.com/facts/1999/BrianLey.shtml" target="_blank" class="externalLink ProxyLink" data-proxy-href="https://hypertextbook.com/facts/1999/BrianLey.shtml" rel="nofollow">https://hypertextbook.com/facts/1999/BrianLey.shtml </a></p><p><span style="color: rgb(255, 0, 0)"><br /></span></p><p><span style="color: rgb(255, 0, 0)"><u>Legend </u></span> (Flaxen hair):</p><p>1/1500 = 0.000666&quot; (rounded ^ = 0.0007&quot; or seven-ten-thousandths inch</p><p>1/500 = 0.002&quot; or two-thousandths inch</p><p>Reference: 10-6&nbsp; = 0.000 001 inch</p><p><br /></p><p>1 micro-meter = 1 millionth of a meter = (39.3700787401 <b>÷</b> 1,000,000.) = 0.00003937007 = (0.000040&quot; rounded ^) = &quot;forty-millionths&quot;.</p><p><br /></p><p>17–50 µm (micrometers) = 0.0007 &quot;- 0.002&quot; diameter range for flaxen hair (blond).</p><p>56–181 µm 0.0022&quot; - 0.007&quot; diameter range for black hair.</p><p><br /></p><p>We have microscopes with multiple-power settings, but apparently no one with access to a professional-quality instrument and having concurrent interest in coin grading has thought it would be of general interest to take on the project of measuring hairline-size imperfections and then published their findings for numismatist !</p><p><br /></p><p>With the plethora of technical information available on a vast panorama of subjects, I wonder why this has not been done already and at least briefly covered in the Red Books ?</p><p><br /></p><p>I think I&#039;ve given a brief coverage here of scratch level width (depth and length being still &quot;up in the air&quot;.), but I&#039;ll have to rely on someone else to tackle hairlines , since all I have is a kid&#039;s toy microscope for amateur work left by one of my sons and now in retirement I can&#039;t justify buying a high quality scope on my SS income.</p><p><br /></p><p>&quot;Hairlines are microscopic scratches that show up as incuse lines,&quot; <font size="6"><span style="color: rgb(255, 0, 0)"> ← </span></font>Stated in 3rd paragraph down of following ANACS link.</p><p><a href="http://www.anacs.com/(A(2pIs3toOzwEkAAAAOTRlZTY2NDItOTM0My00OTI4LTlhYTktZjY4ODczMTRlNjQ29JQW-Sx2-kh_0Ke-qHYuoLRyJmE1)S(rrc4z0u3vmiowezwdza2pwyi))/contentPages/ShowArticle.aspx?ID=7&amp;AspxAutoDetectCookieSupport=1" target="_blank" class="externalLink ProxyLink" data-proxy-href="http://www.anacs.com/(A(2pIs3toOzwEkAAAAOTRlZTY2NDItOTM0My00OTI4LTlhYTktZjY4ODczMTRlNjQ29JQW-Sx2-kh_0Ke-qHYuoLRyJmE1)S(rrc4z0u3vmiowezwdza2pwyi))/contentPages/ShowArticle.aspx?ID=7&amp;AspxAutoDetectCookieSupport=1" rel="nofollow">http://www.anacs.com/(A(2pIs3toOzwEkAAAAOTRlZTY2NDItOTM0My00OTI4LTlhYTktZjY4ODczMTRlNjQ29JQW-Sx2-kh_0Ke-qHYuoLRyJmE1)S(rrc4z0u3vmiowezwdza2pwyi))/contentPages/ShowArticle.aspx?ID=7&amp;AspxAutoDetectCookieSupport=1</a></p><p><br /></p><p>ToddB67[/QUOTE]</p><p><br /></p>

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