RE: BL vs BLB tubes for cyanotype

From: Eric Neilsen ^lt;>
Date: 11/16/05-08:44:54 PM Z
Message-id: <001201c5eb20$e49ef270$51a0fea9@NEWDELL>

Sandy, The other glass to you may be Sapphire, but I am NOT confused. I have
not seen Sapphire data, heard it mentioned or otherwise ever thought of
Sapphire glass. : ) I too failed to find Solarphire on PPGs site, but did
see many many glass product that start with Solar.


I have emailed them and will also call.


Eric Neilsen Photography

4101 Commerce Street

Suite 9

Dallas, TX 75226



From: Sandy King []
Sent: Wednesday, November 16, 2005 8:19 PM
Subject: RE: BL vs BLB tubes for cyanotype




The other glass is called Sapphire, not Salarphre, and it is not a glass
that blocks UV. In fact, it allows a very high percentage of transmission of
UV, down to 200 nm. Go to and look at optmat.htm.
>From the site, "Sapphire is a synthetic, single crystal aluminium oxide.
Because of its structure, it exhibits large optical anisotropy and the exact
characteristics depend upon the orientation of the optical axis. Sapphire
has five times the strength of fused silica and superior optical
transmission in both the UV and the IR." Transmission of UV light is 80% at
300 nm, 70% at 250 nm.


I don't have any information about the Salarphire you mention.







No I am not confused. The papers that I have state quite clearly Starphire,
PP&G. I also received information about their clear glass and Solarphire
glass. The Solarphire glass while it might sound interesting, is quite
opposite from what we like in alt photo, it is a glass that blocks much of
the UV light. It is true I have not gone back and requested more data from
PP&G, and the information I got from them was well before the internet made
communication so fast. I will go check out the site, but I still offer the
copies of the hard copies in my files from PP&G. Sandy I am not in a
position to do independent UV transmission readings, but If I stated it back
in...1999, it came from the pages provided to me from PP&G back in 1992. Is
it possible that todays' Starphire is not the same as glass made in 1992?
Quite possibly. Back soon...


Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
> -----Original Message-----
> From: Sandy King []
> Sent: Wednesday, November 16, 2005 6:22 PM
> To:
> Subject: RE: BL vs BLB tubes for cyanotype
> Eric,
> I am puzzled by some statement you have made about Starphire. In your
> messages of today you have suggested that Starphire glass transmits a
> significant percentage of radiation below 350 nm. And you have been
> saying this for a very long time. For example, in a message to the
> alt-photo-list back in December of 1999 you wrote, and I cite the
> message:
> On Sat, 4 Dec 1999, Eric Neilsen wrote:
> OK , I found my charts. Starphire transmits 35.5 % of UV light @
> 300nm where Standard transmits .3%; @310nm 53.1% Star and .8%
> Standard; @320nm 67.9% Star and 9.1% Standard,; @330nm 79.2% Star and
> 34.4% Standard; @340 86.1% Star and 61% Standard; @350nm 89.1% and
> 77% . At 360nm and above it stays at about 91% for Starphire and 86%
> for
> Standard.
> Contrast your information with the specifications in this link,,
>, which gives the following
> figures. Unless I am missing something terribly obvious, your figures
> are very different from those at this source, which are:
> Starphire Glass
> Transmisson: (@ 5.6mm thick)
> @330 nm < 5%
> @350 50%
> @380-680 nm 90%+
> I am wondering if somewhere in your research you did not confuse
> Starphire glass with Sapphire glass? In fact, the figures you cited
> in the 1999 message for Starphire are much closer to current
> transmission figures I was able to get today on the web for Sapphire
> glass.
> Sandy

Received on Wed Nov 16 20:45:13 2005

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