Bizarre Barometer paint fade!

[Bramblestick]

Just noticed this strange thing!

For the last 12 years, we've had an aneroid barometer hanging in the hall - it's probably 1930's by the look of it, and the top half of the dial is printed in black text, and the bottom in red. I've just noticed the the bottom half has disappeared! If you look at it from an oblique angle, you can see the print, but it has faded to nothing!. The device is in a really dark nook, getting no natural light, and for at least the last 5 years the area is lit 24/7 by a lamp on a bureau - some 18" away (Philips compact fluorescent for the last 3 years or so). The lamp has a fabric shade, and the barometer's dial has a glass cover. It's not something that I look at in detail every day - I've got the internet for the weather ;-), but I know that I calibrated it a couple of years ago & didn't notice any problem..

Any insight?

Cheers, Bramblestick

[ss]

Not quite sure but red in past years was prone to fading, modern paints are better but as your item was painted way back I would have expected some fading, now linked to fluorescent rays there maybe an accelerator in there somewhere and at 18" away and probably some heat damage over a long period. Red in hair dyes even today is the most prone to colour fade. red cars in the 70s 80s used to fade quite quickly as well.

So I think red will fade but something has accelerated it and I suspect the fluorescent light.

[Dave Liquorice]

I think CFL's push out rather more than just visible light. Not high levels of UV but enough over a long period of time to affect things

[<me9]

UV light. Fluorescents (of any type, cfl or long tube) are notorious for causing the fading you mention.

[Brian Gaff]

I find that hard to believe considering the low lux levels involved. Other ideas, when it was calibrated, was it removed or cleaned? Could it be that the damage was there but some kind of recent shock or trauma has made brittle paint simply fall away?

Brian

[Terry Fields]

In the 'Chernobyl' thread above someone gave a link to a radon radiation web site, which also contained a link to this, which you might find interesting:

concerns some health risks from CFLs.

Terry Fields

[Graham.]

There's an interesting piece about airport backscatter imaging on that site that puts the perceived hazard into perspective, by comparing it with the cosmic radiation exposure in the ensuing flight.

[Newshound]

Others have mentioned UV, but some red inks as found in hand drawn maps, legal documents, etc. fade faster than the black even in the absence of light. Probably oxidation.

[The Natural Philosopher]

I printed some inkjet decals and left em on a window sill half obscured by an ornament.

In the shade they stayed red. In sunlight with UV they were wiped out red wise.

Its something in that particular red dye.

[docholliday]

I seem to remember that just about all the bright red pigments and dyes that you could make reasonably inexpensive paints and printing inks from were prone to fading in light, or chemically by reacting with air, or toxic - or some combination of the three, although this may have improved in recent years. On the other hand, carbon black was (and is) commonly used as the pigment in black paints and printing inks, and is very stable, as are various black, brown and yellow pigments based on Iron oxide. I've seen lots of dials where red printing has faded while the black is as good as new, even when they were only in indirect sunshine - so a fluorescent lamp only 18 inches away could possibly have the same effect.

[The Natural Philosopher]

Reds are notorious for UV fading.

Especially organic pigments.

no bad idea to put a UV barrier lacquer over reds..apparently.

[Jonathan]

You can buy UV filtering glass, which I have put on a couple of water colours that I mind about.

Jonathan

[Bramblestick]

Thanks everyone. I'm going for the UV from the CF - will look into that in greater detail. It's a pity, however.

Cheers, Bramblestick

[The Natural Philosopher]

it is for sure.

it may be possible to resurrect it but I would not know how.