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<p>[QUOTE=&quot;ToughCOINS, post: 8292418, member: 20480&quot;]Lighting in the top photo appears to be from the coin&#039;s 8:00 clock position.</p><p><br /></p><p>In the lower photo, the lighting seems to originate at about the coin&#039;s 4:00 position.</p><p><br /></p><p>Surface area perpendicular to the light source determines how concentrated and bright the reflected light is.</p><p><br /></p><p>1.&nbsp; Light directed along the length of the scratch will reflect in the direction of the scratch.&nbsp; One might expect the light reflected by the full length of the scratch to be very bright, but it will be diffuse because of the varying angle of incidence (think varying focal distance and / or depth of field for a lens) along the length of the scratch.</p><p><br /></p><p>2.&nbsp; Lighting from 6:00 or 12:00 would reflect out the far end of the scratch, and not perpendicular to it, as would lighting from 3:00 or 9:00.</p><p><br /></p><p>3.&nbsp; The scratch is not straight.&nbsp; Curved as it is, I&#039;d expect the reflected light from 3:00 to concentrate more, as if reflected by a parabolic mirror, while light directed at the scratch from 9:00 should disperse somewhat, and be less bright.[/QUOTE]</p><p><br /></p>

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