<html><head></head><body><div style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div><div>The UV range for the "A" portion of UV is considered <span>
315–400nm. (the B and C ranges are harmful, and must be avoided. But don't worry about those, because no versions of those existing for theater or DJ-ing.)<br></span></div><div><span><br></span></div><div><span>Most of the sources I have read indicate that 400nm is the limit for human vision. Though, I suspect it is not a hard cut-off. There are many documented people who seem to be sensitive well beyond the 400nm limit.<br></span></div><div><span><br></span></div><div><span>I find that now I am in my 50's, when I am in a place flooded with UV light, my vision is hazy. It was not like that when I was younger. So, I imagine that either my lens or cornea is fluorescing a bit, so that I "see" UV.<br></span></div><div><span><br></span></div><div><span>As an aside, during WWII, old men, who had their lenses removed because of cataracts, were utilized to see UV signal lights from ships and submarines. At the time, there were no implantable lenses, and it is the lens that blocks UV light. The retina itself is sensitive to UV.<br></span></div><div><span><br></span></div><div><span>-Joe<br></span></div><div><span></span><br></div><div>On Fri, Oct 5, 2018 at 3:34 PM George Davidson via Stagecraft <<a shape="rect" href="mailto:stagecraft@theatrical.net" rel="nofollow" target="_blank">stagecraft@theatrical.net</a>> wrote:</div><div class="ydp68906f3cyiv9014921137gmail_quote"><div class="ydp68906f3cyiv9014921137yqt0775846039" id="ydp68906f3cyiv9014921137yqt63073"><blockquote class="ydp68906f3cyiv9014921137gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div dir="ltr"><div>This isnt true UV, more like dark purple, they are showing 385-405, good UV is 365mn</div></div></blockquote></div></div></div></div></body></html>