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<p>[QUOTE=&quot;-jeffB, post: 4918086, member: 27832&quot;]Okay, here&#039;s one question I&#039;ve had for a while: <b>outside of checking toning</b> (including copper color), why does CRI <i>matter</i> for inspecting coins? You&#039;re looking for <i>topographic</i> detail on the coin&#039;s surface. Contact marks, wear, scratches, flow lines -- those all look the same <i>independent</i> of color, so it seems like your source&#039;s CRI shouldn&#039;t be important. Maybe for spotting certain stains...?</p><p><br /></p><p>What <i>does</i> seem like it should be important:</p><p><br /></p><p><b>Intensity</b> -- if your light is too dim, it&#039;s hard to make out small features, including scratches and dings. As your pupils dilate, your vision&#039;s focus becomes <i>less</i> sharp (although that&#039;s a bit of an oversimplification). But if the light&#039;s too <i>bright</i>, it can dazzle and wash out details.</p><p><br /></p><p><b>Angular extent</b> (point-source vs. large-area source) -- a point source should be best for picking out scratches and other texture features (including luster). A wide, diffuse source reduces the highlights and shadows those features cast, and so reduces their contrast.</p><p><br /></p><p><b>Absence of flicker</b> -- because flicker will drive you crazy, and give you headaches.</p><p><br /></p><p><b>Heat</b> -- because who wants to roast while examining coins?</p><p><br /></p><p>The thing that most gave me pause in the ANA recommendations was the bit about &quot;avoiding halogen because it&#039;s too bright and washes out detail&quot;. Like I said before, intensity is a <i>separate variable</i>. If your light&#039;s just too bright, move it further away, or put a neutral-density filter in front of it.[/QUOTE]</p><p><br /></p>

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