Message:

<p>[QUOTE=&quot;-jeffB, post: 1212187, member: 27832&quot;]Forgive me for nitpicking here, but I&#039;m a bit of a lighting geek, and I can&#039;t help myself. <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie1" alt=":)" unselectable="on" unselectable="on" /></p><p><br /></p><p>I&#039;m guessing that most good numismatic references date from a time when incandescent bulbs were the only ones commonly available in small sizes -- a &quot;fluorescent bulb&quot; was a four-foot tube, and anything else (arc lamp, laser, etc.) was a specialty item.</p><p><br /></p><p>A broad-area light source like a non-compact fluorescent hides some features, like the hairlines the original post mentioned. To reveal those, you want a small-area source or a point source. An incandescent bulb a few feet distant works reasonably well. (Direct sunlight could work even better, except that it&#039;s too bright, and not always available.)</p><p><br /></p><p>I imagine that there would be no practical difference between an incandescent bulb and a CFL of comparable size and brightness. A high-intensity, small-area LED would probably highlight hairlines even more than a conventional bulb; this might be a good thing or a bad thing for grading.</p><p><br /></p><p>I&#039;m not sure color-spectrum issues come into play for grading, because you&#039;re looking at topographical features, at a scale where all colors of light behave the same way. (Of course, this neglects toning, where color rendition matters <i>very</i> much.)</p><p><br /></p><p>If there really is an advantage to incandescent light other than the dimensions and brightness of the emitter, I&#039;d be interested to hear more details. Do any of your references say anything about clear vs. frosted bulbs (which would affect the effective size/area of the source)?[/QUOTE]</p><p><br /></p>

Your name or email address:

Do you already have an account?

• No, create an account now.
• Yes, my password is:
• Forgot your password?

Stay logged in