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Hey Mark, Here are some replies: 1 - And I even tried to put it in "sesamstraat" level 2 - The same problem happens with spectacle lenses, the lens itself does not scratch, but the coating does... I assume Breitling amongst others does it for cosmetic purposes and takes the risk of 'wear and tear' for granted 3 - En ja, ik kom inderdaad uit Nederland (omgeving Den Haag) 4 - I assume they are yellowish because normally a coating consists of multiple layers, around 5 - 9, it might be not all of it is gone after the accidental polishing. Regards, René

Hey Mark, I am an Optometrist so I do know some about coatings... Light is reflected at both interfaces of an AR coating. The two reflected wave trains of a certain wavelength can cancel each other out totally by interference if both the phase and amplitude requirements are met. By the appropriate choice of layer thicknesses and layer types, the phase requirement can be met for the reference wavelength (wavelength for which the AR coating is optimized). Interference then leads to a minimization of residual reflection. To achieve this, the layer thickness (t) must total one quarter of the reference wavelength. The thickness is just a few microns (1/1000 of a mm.) By appropriately selecting the refractive indices of the AR coating layers, interference leads to a minimization of residual reflections. A suitable combination of lens and AR coating materials is decisive if the AR coating is to have an optimum effect. The AR coatings work at different degrees across the color spectrum. Hence the anti-reflectance effect is not the same for all colors, which results in a slight color change to the lens. This color change can be controlled so that you get a pleasing cosmetic tint, such as light green, blue or red; which improves the overall appearance of the lens or in this case watch crystal. When you polish the front of the crystal, (some) of the coating will wear off like an abbrasion. When you want to completely remove th front caoting you can try to polish it of, but it will be difficult to get a nice evenely result. When we want to remove a coating from e.g. spectacle lenses we dip them in a sulphuric acid (zwavelzuur) solution for a few minutes and rinse them with water. However this will take off both sides' coating (in and out) . The most of the blueish bloom comes from the front face reflection, and a little from the back, so when you take the outer of you will lose most of the blue reflection. I assume it is cheaper to replace the crystal instead of having it re-coated. René

Hi guys, I am considering to buy Andrews ROLSUB0013 - Rolex "PERFECT" SS Submariner - Black - Swiss ETA Not only de rehaut and the new cg's , but als the pre-service and the waterproofing look promising. Is there anyone who owns one, or has experiences with it... Thx. René

Is that what keeps your drive hard