<div dir="auto">Interesting! <div>Thank you Dana! </div><div>But it gives no
idea of the maximum quantity of lumens of a light which is behind my red
filter. <br><br>Thierry </div></div><div
style="line-height:1.5"><br><br>-------- Message original --------<br>De : Dana
Myers <dana.myers@xxxxxxxxx><br>Date : jeu. 7 oct. 2021 à 17:53<br>À :
pure-silver@xxxxxxxxxxxxx<br>Objet : [pure-silver] Re: [pure-silver] Re :
[pure-silver] Re: =?UTF-8?Q?Light_in_the_Lab<br><blockquote><div>
<div>On 10/7/2021 8:40 AM,
<a
href="mailto:thierry.arnaud@xxxxxxxxxxxx";>thierry.arnaud@xxxxxxxxxxxx</a>
wrote:<br />
</div>
<blockquote>
<div dir="auto">Thanks for your answer.
<div>I know this method you indicated. But what I want is to
know before building my safelight what quantity of light,
expressed in Lumens, could be supported by the paper. The
measurement in Watts is not accurate because Watts is just a
power-measurement, not a light one. </div>
<div><br />
</div>
<div>Best, <br />
</div>
</div>
</blockquote>
<br />
I consulted <a href="http://www.google.com";>www.google.com</a> by entering
"25w fluorescent light tube
lumens", the first<br />
result was:<br />
<br />
<a
href="https://www.amazon.com/Philips-Lighting-280925-Standard-Fluorescent/dp/B00B5GFRY2";>https://www.amazon.com/Philips-Lighting-280925-Standard-Fluorescent/dp/B00B5GFRY2</a><br
/>
<br />
Which gives 2150 Lumens for luminous flux.<br />
<br />
This is just one example; the same process can find more.<br />
<br />
Cheers,<br />
Dana K6JQ<br />
<br />
<br />
<br />
<blockquote>
<div dir="auto">
<div><br />
Thierry ARNAUD </div>
</div>
<div style="line-height:1.5"><br />
<br />
-------- Message original --------<br />
De : Jeffrey Thorns <a
href="mailto:puresilver@xxxxxxxxx";><puresilver@xxxxxxxxx></a><br />
Date : jeu. 7 oct. 2021 à 17:15<br />
À : <a
href="mailto:pure-silver@xxxxxxxxxxxxx";>pure-silver@xxxxxxxxxxxxx</a><br />
Objet : [pure-silver] Re: Light in the Lab<br />
<blockquote>
<div>I use some old Arkay sleeves over 24" florescent tubes.
The tubes are 25 watts.<br />
<br />
You can always do a coin test.<br />
<br />
Set up to do some printing<br />
Turn all lights off<br />
Pull out a test strip of paper and lay it on the counter<br />
Place a quarter on the strip<br />
Turn on your safelights and let the test strip sit there for
a few minutes<br />
Process the test strip and see if you can see the quarter
outlined<br />
If you can, the safelights aren't safe<br />
<br />
<blockquote style="border:0px none">
<div style="margin:30px 25px 10px 25px">
<div style="display:table;width:100%;border-top:1px solid
#edeef0;padding-top:5px">
<div
style="display:table-cell;vertical-align:middle;padding-right:6px"><img
src="cid:part1.02010808.08070604@snarf.net" width="25px" height="25px" /></div>
<div
style="display:table-cell;white-space:nowrap;vertical-align:middle;width:100%">
<a href="mailto:thierry.arnaud@xxxxxxxxxxxx" ;
style="color:#737f92
!important;padding-right:6px;font-weight:bold;text-decoration:none
!important">Thierry ARNAUD
(aristark.com)</a></div>
<div
style="display:table-cell;white-space:nowrap;vertical-align:middle">
<font color="#9FA2A5"><span style="padding-left:6px">October
7, 2021 at 6:56 AM</span></font></div>
</div>
</div>
<div style="color:#888888;margin-left:24px;margin-right:24px">
<div>
<p><span style="font-size:12pt;font-family:'new
roman' serif">Good Morning,</span></p>
<p><span style="font-size:12pt;font-family:'new
roman' serif"> </span></p>
<p><span style="font-size:12pt;font-family:'new
roman' serif">I am building my new lab for printing. </span></p>
<p><span style="font-size:12pt;font-family:'roman'
serif">I bought a big sheet of gelatine filter at
LeeFilter’s. It is a 789 Blood Red Filter </span></p>
<p><span style="font-size:12pt;font-family:'new
roman' serif"><a
href="https://www.leefilters.com/lighting/colour-details.html#789";>https://www.leefilters.com/lighting/colour-details.html#789</a></span></p>
<p><span style="font-size:12pt;font-family:'new
roman' serif">I guess it is a good one for lighting the
lab without damage the photographic papers.</span></p>
<p><span style="font-size:12pt;font-family:'new
roman' serif">But I have a question : which quantity of
light (Lumen) can I use behind the Blood Red
Filter without veiling my photographic paper ?</span></p>
<p><span style="font-size:12pt;font-family:'new
roman' serif">In my books, I find only the wavelength but
nothing about the quantity of Lumen.</span></p>
<p><span style="font-size:12pt;font-family:'new
roman' serif"> </span></p>
<p><span style="font-size:12pt;font-family:'new
roman' serif">Does <span style="color:#1f497d">any</span>body
know something<span style="color:#1f497d">
</span>precisely
about this point ?</span></p>
<p><span style="font-size:12pt;font-family:'new
roman' serif"> </span></p>
<p><span style="font-size:12pt;font-family:'new
roman' serif">Many thanks in advance for your answer,</span></p>
<p><span style="font-size:12pt;font-family:'roman'
serif"> </span></p>
<p><span style="font-size:12pt;font-family:'new
roman' serif">Best regards,</span></p>
<p><span style="font-size:12pt;font-family:'new
roman' serif"> </span></p>
<p><span style="font-size:12pt;font-family:'new
roman' serif">Thierry ARNAUD</span></p>
<p><span style="font-size:12pt;font-family:'roman'
serif">(France)</span></p>
<p> </p>
</div>
</div>
</blockquote>
</div>
</blockquote>
</div>
</blockquote>
<br />
</div>
</blockquote></div>
