I just replaced a Philips 120 cm 827 with an Osram, as the Philips was
flickering badly, and replacing the ballast hadn't helped. Couldn't
get a Philips near where I lived, and I doubt if anyone does 120 cm
fluorescent tubes mail-order at any reasonable price, if at all.

I noticed that the spectrum emitted by the Osram was significantly
different to the tube next to it - the Osram being of a more greenish
cast (or the adjacent fitting more pinkish). (The tubes are adjacent
to a white tiled splashback). I swore gently under my breath. So off I
go to another room to extract what I thought was an existing Philips
tube to swap, so I could get the same spectrum in fittings next to
each other. This was working on the assumption that the phosphor mix
between the Philips and the Osram 'Warn White' was sufficiently
different to show up as different emission spectra.

Now here's the odd thing. The older tube had a spectrum that matched
the older fitting in the kitchen - which was good news, but wasn't a
Philips - but in fact another Osram. The older fitting has a Philips
tube.

So, I'm lucky to get a colour match good enough for my eyes, but now
intrigued: do fluorescent tube emission spectra change subtly over
time as they age? It's the only explanation that makes sense to me.

It is also incredibly irritating. It looks like that if I have
multiple fluorescent fixtures in a room, changing any one of the tubes
will stand out like a sore thumb until it is 'run in'. Yet another
irritation to deal with when using 'energy efficient' lighting.

Grump over.

Sid

In article ,
writes:
I just replaced a Philips 120 cm 827 with an Osram, as the Philips was
flickering badly, and replacing the ballast hadn't helped. Couldn't
get a Philips near where I lived, and I doubt if anyone does 120 cm
fluorescent tubes mail-order at any reasonable price, if at all.

I noticed that the spectrum emitted by the Osram was significantly
different to the tube next to it - the Osram being of a more greenish
cast (or the adjacent fitting more pinkish). (The tubes are adjacent
to a white tiled splashback). I swore gently under my breath. So off I
go to another room to extract what I thought was an existing Philips
tube to swap, so I could get the same spectrum in fittings next to
each other. This was working on the assumption that the phosphor mix
between the Philips and the Osram 'Warn White' was sufficiently
different to show up as different emission spectra.

Now here's the odd thing. The older tube had a spectrum that matched
the older fitting in the kitchen - which was good news, but wasn't a
Philips - but in fact another Osram. The older fitting has a Philips
tube.

So, I'm lucky to get a colour match good enough for my eyes, but now
intrigued: do fluorescent tube emission spectra change subtly over
time as they age? It's the only explanation that makes sense to me.

They do, which is one reason why installations where this is critical
are relamped altogether. However, Osram as a name has moved between
several companies over the years, and it's more likely that the
phosphor formulation isn't the same between the old and new tube.
827 designation doesn't guarantee the same spectrum.

It is also incredibly irritating. It looks like that if I have
multiple fluorescent fixtures in a room, changing any one of the tubes
will stand out like a sore thumb until it is 'run in'. Yet another
irritation to deal with when using 'energy efficient' lighting.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 25 Apr, 11:04, (Andrew Gabriel) wrote:
In article ,
* * * * writes:



I just replaced a Philips 120 cm 827 with an Osram, as the Philips was
flickering badly, and replacing the ballast hadn't helped. Couldn't
get a Philips near where I lived, and I doubt if anyone does 120 cm
fluorescent tubes mail-order at any reasonable price, if at all.

I noticed that the spectrum emitted by the Osram was significantly
different to the tube next to it - the Osram being of a more greenish
cast (or the adjacent fitting more pinkish). (The tubes are adjacent
to a white tiled splashback). I swore gently under my breath. So off I
go to another room to extract what I thought was an existing Philips
tube to swap, so I could get the same spectrum in fittings next to
each other. This was working on the assumption that the phosphor mix
between the Philips and the Osram 'Warn White' was sufficiently
different to show up as different emission spectra.

Now here's the odd thing. The older tube had a spectrum that matched
the older fitting in the kitchen - which was good news, but wasn't a
Philips - but in fact another Osram. The older fitting has a Philips
tube.

So, I'm lucky to get a colour match good enough for my eyes, but now
intrigued: do fluorescent tube emission spectra change subtly over
time as they age? It's the only explanation that makes sense to me.

They do, which is one reason why installations where this is critical
are relamped altogether. *However, Osram as a name has moved between
several companies over the years, and it's more likely that the
phosphor formulation isn't the same between the old and new tube.
827 designation doesn't guarantee the same spectrum.

It is also incredibly irritating. It looks like that if I have
multiple fluorescent fixtures in a room, changing any one of the tubes
will stand out like a sore thumb until it is 'run in'. Yet another
irritation to deal with when using 'energy efficient' lighting.


Thanks Andrew.

While I'm being irritated, I'll grump again that there's nothing on
the old tube or new tube (that I can see) that allows me so see of the
phosphor formulations are the same. As you say, if it is critical, it
looks like I'll have to replace all at once.

I haven't got around to replacing the fittings with dimmable high
frequency ballasts and tubes with higher CRIs yet (as recommended to
me in this group, possibly even by you). The flicker on the current
fittings gets to me occasionally - noticeable in my peripheral vision,
especially when I have a headache.

Thanks again.

Sid

wrote:
On 25 Apr, 11:04, (Andrew Gabriel) wrote:
In article ,
* * * * writes:



I just replaced a Philips 120 cm 827 with an Osram, as the Philips was
flickering badly, and replacing the ballast hadn't helped. Couldn't
get a Philips near where I lived, and I doubt if anyone does 120 cm
fluorescent tubes mail-order at any reasonable price, if at all.

I noticed that the spectrum emitted by the Osram was significantly
different to the tube next to it - the Osram being of a more greenish
cast (or the adjacent fitting more pinkish). (The tubes are adjacent
to a white tiled splashback). I swore gently under my breath. So off I
go to another room to extract what I thought was an existing Philips
tube to swap, so I could get the same spectrum in fittings next to
each other. This was working on the assumption that the phosphor mix
between the Philips and the Osram 'Warn White' was sufficiently
different to show up as different emission spectra.

Now here's the odd thing. The older tube had a spectrum that matched
the older fitting in the kitchen - which was good news, but wasn't a
Philips - but in fact another Osram. The older fitting has a Philips
tube.

So, I'm lucky to get a colour match good enough for my eyes, but now
intrigued: do fluorescent tube emission spectra change subtly over
time as they age? It's the only explanation that makes sense to me.

They do, which is one reason why installations where this is critical
are relamped altogether. *However, Osram as a name has moved between
several companies over the years, and it's more likely that the
phosphor formulation isn't the same between the old and new tube.
827 designation doesn't guarantee the same spectrum.

It is also incredibly irritating. It looks like that if I have
multiple fluorescent fixtures in a room, changing any one of the tubes
will stand out like a sore thumb until it is 'run in'. Yet another
irritation to deal with when using 'energy efficient' lighting.


Thanks Andrew.

While I'm being irritated, I'll grump again that there's nothing on
the old tube or new tube (that I can see) that allows me so see of the
phosphor formulations are the same. As you say, if it is critical, it
looks like I'll have to replace all at once.

I haven't got around to replacing the fittings with dimmable high
frequency ballasts and tubes with higher CRIs yet (as recommended to
me in this group, possibly even by you). The flicker on the current
fittings gets to me occasionally - noticeable in my peripheral vision,
especially when I have a headache.

Thanks again.

Sid


FWIW, if its just the flicker that bothers you, its possible to add a
series capacitor to an existing ballast to turn it into a leading
power factor ballast. Now, 2 fittings, one lead one lag, and you get a
lot less flicker overall. And since you've still got a large inductace
in circuit, its not affected by the issues ready made lead lag
ballasts have.

BUT don't experiment, the cap value is somewhat critical, get it wrong
and you'll have a problem.
See Droppers on the wiki for more info.


NT

On 25 Apr, 12:36, wrote:
wrote:
On 25 Apr, 11:04, (Andrew Gabriel) wrote:
In article ,
* * * * writes:

I just replaced a Philips 120 cm 827 with an Osram, as the Philips was
flickering badly, and replacing the ballast hadn't helped. Couldn't
get a Philips near where I lived, and I doubt if anyone does 120 cm
fluorescent tubes mail-order at any reasonable price, if at all.

I noticed that the spectrum emitted by the Osram was significantly
different to the tube next to it - the Osram being of a more greenish
cast (or the adjacent fitting more pinkish). (The tubes are adjacent
to a white tiled splashback). I swore gently under my breath. So off I
go to another room to extract what I thought was an existing Philips
tube to swap, so I could get the same spectrum in fittings next to
each other. This was working on the assumption that the phosphor mix
between the Philips and the Osram 'Warn White' was sufficiently
different to show up as different emission spectra.

Now here's the odd thing. The older tube had a spectrum that matched
the older fitting in the kitchen - which was good news, but wasn't a
Philips - but in fact another Osram. The older fitting has a Philips
tube.

So, I'm lucky to get a colour match good enough for my eyes, but now
intrigued: do fluorescent tube emission spectra change subtly over
time as they age? It's the only explanation that makes sense to me.

They do, which is one reason why installations where this is critical
are relamped altogether. *However, Osram as a name has moved between
several companies over the years, and it's more likely that the
phosphor formulation isn't the same between the old and new tube.
827 designation doesn't guarantee the same spectrum.

It is also incredibly irritating. It looks like that if I have
multiple fluorescent fixtures in a room, changing any one of the tubes
will stand out like a sore thumb until it is 'run in'. Yet another
irritation to deal with when using 'energy efficient' lighting.

Thanks Andrew.

While I'm being irritated, I'll grump again that there's nothing on
the old tube or new tube (that I can see) that allows me so see of the
phosphor formulations are the same. As you say, if it is critical, it
looks like I'll have to replace all at once.

I haven't got around to replacing the fittings with dimmable high
frequency ballasts and tubes with higher CRIs yet (as recommended to
me in this group, possibly even by you). The flicker on the current
fittings gets to me occasionally - noticeable in my peripheral vision,
especially when I have a headache.

Thanks again.

Sid

FWIW, if its just the flicker that bothers you, its possible to add a
series capacitor to an existing ballast to turn it into a leading
power factor ballast. Now, 2 fittings, one lead one lag, and you get a
lot less flicker overall. And since you've still got a large inductace
in circuit, its not affected by the issues ready made lead lag
ballasts have.

BUT don't experiment, the cap value is somewhat critical, get it wrong
and you'll have a problem.
See Droppers on the wiki for more info.

NT

Thanks - doing that is beyond my current safe technical competence. I
should also point out that the two fittings are not parallel, but end-
to end under kitchen cupboards (total length 2.4 metres and a bit) so
the technique wouldn't be applicable. I have heard of it before.

I found the message that pointed me towards high-frequency dimmable
ballasts in he

http://groups.google.co.uk/group/uk....0f3d02a84ac53c

in the uk.d-i-y discussion on "Options for flicker free lighting
source?"

Regards,

Sid

In article ,
writes:
Thanks Andrew.
While I'm being irritated, I'll grump again that there's nothing on
the old tube or new tube (that I can see) that allows me so see of the
phosphor formulations are the same. As you say, if it is critical, it
looks like I'll have to replace all at once.
I haven't got around to replacing the fittings with dimmable high
frequency ballasts and tubes with higher CRIs yet (as recommended to
me in this group, possibly even by you).

I don't recall that, but maybe.

The flicker on the current
fittings gets to me occasionally - noticeable in my peripheral vision,
especially when I have a headache.

You generally have to relamp all tubes in a dimming installation
at the same time, as their dimming characteristics change with
age, and otherwise they will behave differently at lower lighting
levels.

Also, when using new tubes on dimming ballasts, always run them at
full power for first 100 hours.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article
,
wrote:
So, I'm lucky to get a colour match good enough for my eyes, but now
intrigued: do fluorescent tube emission spectra change subtly over
time as they age? It's the only explanation that makes sense to me.

Yes. I work in TV and if fluorescent lighting is used in a location where
it is the main lighting - like say in a walking through a corridor shot
where you can't use extra production lighting - they are all replaced at
the same time. A TV camera is more sensitive to colour temperature
mismatch than the eye.

--
*If I worked as much as others, I would do as little as they *

Dave Plowman London SW
To e-mail, change noise into sound.