Lume Question

[jrpb]

Hi Everyone, my names jon and ive only recently joined RWF
My first Rolex is a 2009 v serial Explorer II and i wondered can any one tell me why the lume on the hands is not as bright as the hour markers around the dial. In the dark i can see the markers clerly but cant really tell the time as i cant see the hands

[taxico]

well, while i don't know why the lume on the dial doesn't match the hands...

i do know that rolex doesn't have the best lume in the watch world (compared to say, seiko's lumibrite).

if you've bought your watch brand new, it is probably fine the way it is... you could "charge" it up a little at night before bed with a torch or something!

if you have doubts about the authenticity of certain parts of a pre-owned watch, you're better off consulting an AD/RSC or posting actual photos of the watch here to ask some of the experts.

(nice choice for a "first rolex" by the way!)

[swissautopro]

Welcome, Jon. Did you purchase your watch from an AD, or some other source?

[Rscmaine]

Long answer?

Here's a Luminova data table from Nemoto & Co, Ltd.

Table Courtesy of
Nemoto & Co Ltd.
LumiNova®
Green

LumiNova®
Blue Green

Conventional
Phosphorescent
Pigment

Chemical Identity Strontium Aluminate Oxide Strontium Aluminate Oxide ZnS:Cu
Body Color Light Yellowish Green Light Blue Yellowish Green
Avg Particle Size 1.5-40μm6 1.5-20μm6 20-40μm
Excitation by 200-450nm 200-450nm 200-450nm
Emission at (peak) 520nm 490nm 530nm
Afterglow Brightness1 >300mcd/m² >200mcd/m² 20-30mcd/m²
Afterglow Extinction2 >2,000 min. >2,000 min. 200min.
Excitation Time3 >30 min. >30 min. 4 min.
Light Fastness4 >1,000 hours >1,000 hours 10-24 hours
Chemical Stability Excellent (Except Water) Excellent (Except Water) Poor to Good
Specific Gravity5 3.6 3.9 4.1
(1) Brightness after 10 min., excitation with a D65 illuminant for 4 min. at 200 lx.
(2) Time span necessary for afterglow brightness to diminish to 0.32 mcd/m²(100 times the human eye perception limit).
(3) Time required for saturation with standard D65 illuminant at 200 lx.
(4) Time required for initial afterglow to drop by 20% after irradiation with 300W high pressure mercury lamp (accelerated light fastness test)
(5) In powder form.
(6) Depends on type of LumiNova® (different particle sizes available).

Ref. Note 4 above, this is saying that if we charge up our lume with lotsa UV for 1000 hrs or more, the lume will be permanently degraded with a 20% loss of brightness.

Ref. Note 6 above, particle size also affects brightness - and here, size matters quite a bit:

Average Particle Size μm 1.4 9 19 42
Glow after 1 hour mcd/m² 10 37 50 63

Even longer answer? http://kronometric.org/article/lume/

Short answer? There is less luminous material on the hands than the markers. For maximum duration luminova must be charged for 30 minutes continuosly

[Green Arrow]

Rolex is not a good choice watch if lume is important to your son. A $300 Seiko diver with Lumibrite will far outshine every single Rolex. Of the Rolex models the Deepsea and new Ceramic sub use Chromolite which is a better quality lume than is used on the Explorer.

The amount of visible lume depends on the amount of area painted with luminous material, and the depth, and the amount of excitation of the molecules that carry the lume, generally caused by "charging" the watch with about 1/2 hour maximum high power flashlight before long periods of darkness. But the Explorer will still not do well in that department.

If your son needs many consectutive hours of lume, but doesn't want to do the "charging" at night, then he should look at Luminox, or similar brands who have watches in which tubes of tritium material have been inserted. These appear dimmer than traditional watches initially, but they hold a steady amount of lume permanently without charging, so after 6 hours of darkness will be brighter than almost all watches, except perhaps a few Seikos/Orient/GP Seahawk II Pro XL.

[AE WIS]

My GMTIIc is the same - hour markers brighter than the hands. My 16610 is more even between hands and markers. Best lume on a watch I have seen: Orient 300m Diver.

[jrpb]

hi everyone and thanks for the replys, i bought the watch from a watch dealer ive used before it came with box and papers and is only 9 months old. I was gazing at it and realized the hands where a slightly different shade and when tested in a dark room it was harder to make out the hands aswell, i wont be exploring dark caves or jungles so not really that im[portant but i was just curious.

[jrpb]

..............oh yeah i dont have a son

[ssmui]

deleted. Apologies.

[ssmui]

My bad.

[SWIMPRUF]

I think Seiko Sawtooth has the best lume IMO.

[le_baroudeur]

My 16610LV has got the same "issue", do not worry about it... My Seiko is stunning on this point, but... you see... I prefer the LV !

[mike]

It's a question that comes up now and then. As mentioned Rolex luminosity has never been the best when compared to some others. Part of it is due to the mixture used by Rolex, but as to why some feel the hands and indices are a different intensity, one wonders if perhaps the incices being more consentrated than the spread out area of the hands has something to do with it?

Just a SWAG, but who knows.

[ally]

Just looking at my Explorer II the hour markers appear bigger and thicker than the hands, maybe that explains it.

Welcome by the way....Love your Avatar