RE: BL vs BLB tubes for cyanotype

Eric,

Well, there was nothing careful about my retrieving of your data. It
came up as the first item on a list when I did a simple google search
"UV transmission of starphire glass."

In any event the current transmission data for Starphire glass, as
seen at the PGG site, is very different from what you posted so I
look forward to what you find out from PP&G so that we can at least
clarify the transmission.

But just for the record, the piece of Starphire glass that I tested
was obtained as a sample from PP&G four or five years ago, perhaps
in early 2000 after the subject of Starphire was discussed on this
list. And it was clearly labeled as Starphire.

Be all that as it may, I still don't believe there is much to be
gained by using a glass with high transmission below about 340 nm, at
least not with BL, BLB and SA tubes. SA tubes put out virtually no
radiation below 350 nm, and even the BLs and BLBs fall off to almost
nothing at around 335 nm.

Sandy

>Sandy, I wanted to make sure that you understand that when I say " my data"
>,I am not talking about the web site or data that I produced, but a spectral
>data sheet issued by PPG back in 1992 that has the data that you so
>carefully retrieved as I posted it back in 1999.
>
>Eric Neilsen Photography
>4101 Commerce Street
>Suite 9
>Dallas, TX 75226
>http://e.neilsen.home.att.net
>http://ericneilsenphotography.com
>
>> -----Original Message-----
>> From: Sandy King [mailto:sanking@clemson.edu]
>> Sent: Wednesday, November 16, 2005 8:51 PM
>> To: alt-photo-process-l@sask.usask.ca
>> Subject: RE: BL vs BLB tubes for cyanotype
>>
>> I went to the site and looked at the .pdf file, but I did not see
>> anything there at all about UV transmission at specific nanometer
>> range.
>>
>> Let me know what you find out from PG&G.
>>
>> Sandy
>>
>>
>> >I am back. The web site you link to is PG&O. The transmission data is
>> indeed
>> >quite different and looks more like Solarphire than Starphire. My data
>> has
>> >the PP&G logo.
>> >
>> >Below is a link to PPG and their Starphire Glass
>> >
>> >http://corporateportal.ppg.com/NR/rdonlyres/F736A32E-E981-4292-A954-
>> C4206B0F
>> >EE97/0/starphire.pdf
>> >
>> >
>> >Eric Neilsen Photography
>> >4101 Commerce Street
>> >Suite 9
>> >Dallas, TX 75226
>> >http://e.neilsen.home.att.net
>> >http://ericneilsenphotography.com
>> >
>> >
>> >> -----Original Message-----
>> >> From: Sandy King [mailto:sanking@clemson.edu]
>> >> Sent: Wednesday, November 16, 2005 6:22 PM
>> >> To: alt-photo-process-l@sask.usask.ca
>> >> 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,,
>> >> http://www.pgo.com/pdf/ppg_starphire.pdf, 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 Thu Nov 17 08:08:30 2005