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Fig. 1

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Fig. 2

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Fig. 3

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Fig. 4

3501: Luminous Paste, Luminova

This product was designed for easiest application and best durability.

Re-emission: Refering brightness and duration, Luminova® (Nemoto) represents the state of the art. For completing flaked off old luminous matter, respectively its imitation, alternatively ZnS luminous paste.is available, but its re-emission is remarkably weaker and shorter.

Luminous paste 3501: ready to use, weight 3g, strontiium-aluminate based pigment (green emission)
Thinner 3505: 3ml (within delivery)
Shelf life: minimum 3 years, stored in dark place with maximum 20°C (68°F)
Main features: Despite maximum filling with pigment still fluid enough to distribute automatically uniformly. Best possible protection of pigment against humidity. The hardener 3506 (not included) improves the application for deeply milled markers and digits in bezels. The luminous pigment is non-toxic and not radioactive. For lacquer and thinner, in the present delivery form, are no safety data sheet and no health labelling required.

Bits and Pieces
I offer few materials and tools which have served me well for many years. They are not the cheapest of their kind, and probably even not the best. So read the item description carefully before the decision to buy them.

Consistency adjustment: For this purpose the bottle must have rested at least four days, to make the pigment settle like in Fig. 2. One recognises at the bottom lacquer, saturated with pigment, and on top lacquer without pigment. The height H1 of this layer should be ca. 20% of the total fill height H, and if less, add thinner drop by drop (e.g. with a screwdriver).
Tolerance: Visual judgement is sufficient. But above H1=30% rings of lacquer without pigment appear around lume dots. And with less than H1=10% the the stability of the cured paste suffers. Prevent that H1 vanishes completely, because this will spoil the paste.
Attention: When estimating H and H1, consider that the high surface tension pulls the lacquer up the bottle wall. A view from the side shows the actual level of the lacquer.
Stirring: Before using the paste it should be stirred intensively, e.g. with a screwdriver. Then the paste is ready to use for some 5 minutes. If the work lasts longer, one should stirr a bit every 5 minutes to keep the optimum ratio between lacquer and pigment..
Fill hands: This is almost always successful already the first time. From the screwdriver used for stirring, a drop is taken with a fine oiler (or needle), preferably from the bottom side of the screw driver. Then the drop is sweeped over the back side of the hand, on wedge shaped apertures beginning at the wide end.. If the drop was too small to fill the whole aperture, a new is taken to continue. Don't mind how to apply the paste - it distributes uniformly almost instantly. The video demonstrates how easy it is:

Set luminous dots: This is a bit tricky, and you should execise on a smooth surface. Again a drop is taken as described above, but now a very tiny, which should sit at the end of the oiler. Then the spot where the dot should be applied is only shortly touched with the drop. The size of the dot is determined by the duration of this contact. You'll get a feeling how long to touch for a desired size, but the first time, it is more reliable to bring the dot step by step to the right size with several very short touches. Again a video shows how easy it is:

Don't be afraid: The videos were made under worst conditions:
1) Applications were done right at the unlucky number "13" on the cm rule.
2) Between camera and object was just 5cm (2 inch) working height, and of course the camera shouldn't be touched.
3) The work could only be watched on the camera display.
Nevertheless no troubles. The hand got a uniform luminous inlay, because the paste distributes uniformly automatically. The dot became round instantly after first touching the cm rule, because the surface tension forces it to do so, and after the second touch it became bigger as expected.
Corrections: For hands it is easy: Wash the hand in any solvent and repeat the job. For luminous dots it is difficult: Too small dots can be enlarged, but too large can't be shrinked. But after about one hour a lume dot is cured enough to remove it completely. Only scarcely a matte spot remains because the paste affects the dial coating, but this will be covered almost completely by the new lume dot.
Tinting (Patina): The paste can be tinted with the ink of water-resistant fine liners or markers. With red, yellow, and blue almost every color of aged lume can be achieved, although the greenish color of the Luminova pigment is a certain restriction. A fine line is painted on the screwdriver to stirr the needed tiny portion of paste. So the desired color can be reached step by step. The re-emission color is hardly affected, but strong tinting will decrease the intensity.

What is known?
1) Ready to use paste based on zinc-sulphide
It can be thinned with water,  but repeated drying and thinning will spoil it soon. Brightness and duration of the re-emission are low. The paste dries fast, and on tiny drops for luminous dots the surface dries already between taking and setting them. So it requires exercise to work fast.
2) Sets with strontium-aluminate pigment, binder and thinner
As the pigment is degraded by water, only water-free ingredients are usable. Mixing small amounts for every application is troublesome, and wastes most material. As the paste dries up slowly, less exercise is necessary. Brightness and duration of the re-emission are much higher compared with ZnS. But at day light the paste appears darker than ZnS, and the yellow-greenish color is distracting for some.

Nothing makes happy
I tested quite some products, and wondered why nothing is avalable which combines the advantages of all. So I experimented with many lacquers, which can be opitimized by additives.

The final lacquer keeps the paste fluid although filled near saturation with pigment. Its matte surface hides the grained structure from the pigment, and brightens up the day-color of strontium-aluminate pigment enough to look like ZnS pigment. It is used as one-component lacquer, but by adding a hardener also as two-components lacquer. So the paste can also be used for the deeply milled markers and digits on diver watch bezels, were a 1c lacquer would need months to cure.

For ZnS pigments are cheap, and one simply takes the best available. The most popular strontiium-aluminate pigments are Luminova from the inventor Nemoto, Super-Luminova, its licensed copy from RC Tritec, and Lumilux from Honeywell. There are no reasonable differences, and Luminova was chosen due to best availability. The highest intensities have pigments with green and blue emission, but as the human eye has its highest sensitivity for green-yellow, there is no real competitor for the green type. So I'll not offer other colors unless they become avalable with comparable brightness.

Fig  3 shows hands with Luminova on the left and ZnS on the right at day light (overcast sky) after  exposing them to this light for 30 minutes. Due to the matte lacquer it is hardly visible that Luminova is darker and greenish.
     Fig. 4 shows these hands with remakably shadowed light, but taken with four times the exposure time to simulate the adaption of the eye to the darkness. So this is how the difference is actually seen.

Sold in Shop

Date 1-8-18

High bid EUR 16.00

Reserve EUR 16.00

Not for Sale!
The item presented here is not for sale. It was offered or sold as mentioned above a longer time ago. This archive is just a market overview and price guide, e.g. for evaluation of comparable items.

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