Luminescent deterioration....WHY?

[Bladerunner]

I noticed that some watch models have dial deterioration more than others
(regarding luminescent - glow ing dark markings on them)

Maybe I don't have enough expirience but seems to me that, that is happening
only on some watches - let's say models who have large "spot" hour markings
on dial (mostly diver's watches)

I watching some Heuer super professional on Ebay and they ALWAYS have
deteriorated luminuous markings (small black spots in large quantities -
like a fungus or something??!!)

Friend of mine have TAG Heuer described model (bought new - some 8 years
ago) and also dial begin to deteriorate... - watch was(is) NEVER opened...
currently 5min/24h late....

I have some old Casio Quartz diver AL-520, I think - my luminuous spots also
deteriorated... (outer borderline of circle)

Anyone know what causes this???

P.s. Everything OK with my Seiko 6309-7040 '83 - original dial I think...

[Leviatan]

"Bladerunner"

>I noticed that some watch models have dial deterioration more than others
> (regarding luminescent - glow ing dark markings on them)
>
> Maybe I don't have enough expirience but seems to me that, that is
> happening
> only on some watches - let's say models who have large "spot" hour
> markings
> on dial (mostly diver's watches)

[...]

Most luminiscent compounds used today are based on organic substances, that
may degrade with time (they loose brigth and get yellow).

In a bit older watches, tritium compound was used (swiss watchmakers
announced this with "T Swiss T" on dials). This is a sligthly radiactive
substance, that can provide ligth for about 20 years, but finally becomes
yellow and even cracks falling from hands and dials. You can have those
dials and hands restored or changed.

--
Kind regards,
Alberto

[Bladerunner]

Alberto have a good point here:

> In a bit older watches, tritium compound was used (swiss watchmakers
> announced this with "T Swiss T" on dials). This is a sligthly radiactive
> substance, that can provide ligth for about 20 years, but finally becomes
> yellow and even cracks falling from hands and dials. You can have those
> dials and hands restored or changed.

>that's true.... (I didn't read descrtiption - My fault....)

description of watch on Ebay...

a.. Dial = original Heuer signed black tritium dial is in good condition
without any wear, original tritium marker has some wear and in a "duck dump"
patina, all writing is clean and visable, signed "T SWISS MADE T" at the
bottom

+ picture....

http://img106.imageshack.us/my.php?image=2a583od0.jpg

+ isn't little bit strange, that marking on a caseback is not well centered
???!

http://img60.imageshack.us/my.php?image=37d63bf7.jpg

pozdrav (regards)

Niksa

[SWG]

little history on luminescent materials for dials and hands:
http://www.europastar.com/europastar/watch_tech/QIT200.jsp

more infos about Superluminova:
http://en.wikipedia.org/wiki/Super-LumiNova and "References" +
"External Links"

[Jack Denver]

In addition to the radioactive deterioration that occurs in the case of
radioactive (tritium, radium) dials (both the deterioration of the lume and
the "radiation burns" that occur on the dial underneath the hands, there is
also natural deterioration of any paint due to exposure to moisture,
sunlight, heat, humidity, etc. and variations in the original paint and
lume formulas. This varies from watch to watch, so the dial of Watch A may
remain in very good condition even though it has been used on a daily basis
and Watch B, which is new old stock, may nevertheless be yellowed, spotted,
etc. - if the hands remain in one place there may be a "shadow".

"Bladerunner" <bladeru...@yahoo.co.uk> wrote in message
news:g4dklu$4ba$1...@ss408.t-com.hr...