In article ,
(Steven Swift) wrote:

According to my DuMont handbook of CRTs, a yellow filter can be
used with a P7 phosphor CRT to allow viewing of the long decay
part without being "blinded" by the bright blue trace. I've searched
Ebay, Sphere Research and other sites looking for these.

Anyone have one good for a 3" round CRT or know of a good substitute
material (perhaps from a hobby store)?

The trusty Wratten 85B (I think) filter used to convert daylight to
tungsten-equivalent lighting for photograpic work is probably about
right. (You want the lighting grade, not the camera filter grade,
as it's a lot cheaper.) Or any suitable stage lighting 'gel' - for
best results, get one that is an exact match for the afterglow, as
that will give you the brightest trace while still knocking down
the blue component.

Tinted Perspex (Plexiglas) may also be worth a try, or even the brown
cellophane you get in some chocolate boxes, sandwiched between two
sheets of clear plastic of glass. (I won't suggest rolling your
own filters out of gelatine and food colouring.... Yet!)

Hope this is some help,

Chris.

--
"It's 106 light-years to Chicago, we've got a full chamber of anti-matter,
a half a pack of cigarettes, it's dark, and we're wearing visors."
"Engage." -- Paul Tomblin in asr

Steve:
Most Tek scopes used an orange filter to view the trace. I may have one from
an old Dumont scope if you want to email me offline.

Ralph ve3bbm at RAC.ca
replace the "at" with the appropriate

"Steven Swift" wrote in message
...
According to my DuMont handbook of CRTs, a yellow filter can be
used with a P7 phosphor CRT to allow viewing of the long decay
part without being "blinded" by the bright blue trace. I've searched
Ebay, Sphere Research and other sites looking for these.

Anyone have one good for a 3" round CRT or know of a good substitute
material (perhaps from a hobby store)?

TIA,

Steve.
--
Steven D. Swift, , http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA

"Ralph Cameron" ha scritto nel messaggio
...
Steve:
Most Tek scopes used an orange filter to view the trace. I may have one
from an old Dumont scope if you want to email me offline.

Ralph ve3bbm at RAC.ca
replace the "at" with the appropriate

"Steven Swift" wrote in message
...
According to my DuMont handbook of CRTs, a yellow filter can be
used with a P7 phosphor CRT to allow viewing of the long decay
part without being "blinded" by the bright blue trace. I've searched
Ebay, Sphere Research and other sites looking for these.

Anyone have one good for a 3" round CRT or know of a good substitute
material (perhaps from a hobby store)?

TIA,

Steve.
--
Steven D. Swift, , http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA


Steven, any photographic deep yellow filter will do.
May be you can find a Kodak, Ilford, or Agfa or similar brand yellow
acetate or gelatin filter.
If you cannot find a deep one, use two filters.
Ciao, Piero

"piero soldi" wrote in message
...

"Ralph Cameron" ha scritto nel messaggio
...
Steve:
Most Tek scopes used an orange filter to view the trace.
I may have one from an old Dumont scope if you want to
email me offline.

Ralph ve3bbm at RAC.ca
replace the "at" with the appropriate

"Steven Swift" wrote in message
...
According to my DuMont handbook of CRTs, a yellow filter
can be
used with a P7 phosphor CRT to allow viewing of the long
decay
part without being "blinded" by the bright blue trace.
I've searched
Ebay, Sphere Research and other sites looking for these.

Anyone have one good for a 3" round CRT or know of a
good substitute
material (perhaps from a hobby store)?

TIA,

Steve.
--
Steven D. Swift, ,
http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington
98155 USA


Steven, any photographic deep yellow filter will do.
May be you can find a Kodak, Ilford, or Agfa or similar
brand yellow acetate or gelatin filter.
If you cannot find a deep one, use two filters.
Ciao, Piero

Another possibility is to use the filter materials made
by Roscoe for photographic lighting. These are sold in large
sheets and come in many colors. They are not expensive. The
idea of the yellow filter is to suppress the bright blue
initial fluorescence of the screen and it should not take
anything too special to do this.
Roscoe is at: http://www.rosco.com/us/ There is a list
of retail stores at the bottom.


--
---
Richard Knoppow
Los Angeles, CA, USA