DemonSlayer Posted November 28, 2007 Report Share Posted November 28, 2007 (edited) I bought a Pam 111h for a low price, with a asian unitas movement. I've noticed that the watch crystal gives off a blue tint when it reflects light. is this possible for a mineral crystal, or is the crystal sapphire? Edited November 28, 2007 by DemonSlayer Quote Link to comment Share on other sites More sharing options...
Victoria Posted November 28, 2007 Report Share Posted November 28, 2007 I bought a Pam 111h for a low price, with a asian unitas movement. I've noticed that the watch crystal gives off a blue tinit when it reflects light. is this possible for a mineral crystal, or is the crystal sapphire? I can't speak for anyone else's experiences, but my low-priced mineral crystal PAMs do not give off a blue-tint. Even the sapphire crystal ones with light AR (well, as advertised), do not. They are "clear" (whitish). The only ones which give off a blue-tint of my arsenal of 17 PAMs, are the two Davidsens, specifically, the DSN 112. Does your watch look like this? That's sapphire crystal, with single-sinded AR (on the underside). It could be that you lucked out or that it's a visual trick. Have you tried the single-drop of water test on it? If it beads and doesn't "bleed", it's more than likely sapphire crystal. FOLLOWUP to reply below: DemonSlayer (cool ID, BTW), does the fluorescent light shining so clearly above you have anything to do with the blue-tint, I wonder? Can you tell the members if the blue-tint (which is definitely there in these photos, beading or not) is present in daylight as well? EDIT: I forgot to mention that my Pizza photo was taken in an outdoor restaurant. So therefore, in natural light. Sssurfer, great info, thanks! @ :sss: -- by special recommendation of the restaurant manager, an Italian from Udine! ...must be some Austrian pizza mix-influence, although it was called "Siciliano". The pizza my friend had was even more disgusting. Artichokes & broccoli. Quote Link to comment Share on other sites More sharing options...
DemonSlayer Posted November 28, 2007 Author Report Share Posted November 28, 2007 I think it might be a optical trick. I wil try the single drop of water test on it, thanks Victoria Quote Link to comment Share on other sites More sharing options...
DemonSlayer Posted November 28, 2007 Author Report Share Posted November 28, 2007 I tried the 1 drop test, it did bleed however and not bead I took some quick photos in my kitchen which uses fluorsecent light, hopefully they can shed some light on the question Quote Link to comment Share on other sites More sharing options...
sssurfer Posted November 28, 2007 Report Share Posted November 28, 2007 That blue tint is the so-called "light AR coat" said by some collectors. It's not true AR, it is just a treatment on glass to give it the look (about color only) of AR coated sapphire. Btw, as Victoria correctly pointed out, sapphire without AR coating is colorless (or it just shows light rose reflections when looked at a step angle, if it is not top-quality sapphire). Davidsen's sapphires are blueish because they are AR coated. @Victoria: pizza cipolle e salame??!!?? (e funghi, ok...) Quote Link to comment Share on other sites More sharing options...
DemonSlayer Posted November 28, 2007 Author Report Share Posted November 28, 2007 Oh I see, so basically my Panerai has a mineral crystal with a so-called light AR coating which is giving it the blueish tint? I am assuming this is common now with the lower end Panerai reps? Quote Link to comment Share on other sites More sharing options...
sssurfer Posted November 28, 2007 Report Share Posted November 28, 2007 Oh I see, so basically my Panerai has a mineral crystal with a so-called light AR coating which is giving it the blueish tint? I am assuming this is common now with the lower end Panerai reps? Yes to both your questions. Quote Link to comment Share on other sites More sharing options...
HauteHippie Posted November 28, 2007 Report Share Posted November 28, 2007 The blue tint is a dyed spray on coating meant to look like an AR coating. It is so "light" that it actually does nearly nothing to reduce reflections. A genuine AR coating would not exhibit such a prominent blue tint on a mineral crystal. Quote Link to comment Share on other sites More sharing options...
8o8 Posted November 28, 2007 Report Share Posted November 28, 2007 so can this be cleaned off and proper AR coating put on? Quote Link to comment Share on other sites More sharing options...
sssurfer Posted November 28, 2007 Report Share Posted November 28, 2007 so can this be cleaned off and proper AR coating put on? It should be. If it is on a sapphire crystal (yes, they also put it on true sapphire crystals in place of AR), an effective way to remove it should be using any abrasive-polishing paste (other than diamond paste!) petroleum-based, or mixed with petroleum. Btw, Cape Cod cloths are like that. This is because sapphire cannot get scratched or made foggy-looking by abrasives. This method is effective in removing true single-side AR coating (low temperature AR coating), so I suppose it should also remove the fake AR coating. If it is on a glass crystal, as in DemonSlayer's watch, don't use abrasives: glass would get damaged. I would try a soft microfiber cloth impregnated with some solvents, starting with acethone. Keeping the crystal sunken under petroleum for 2-3 days before removing the tint might help to do the cloth work easier. Quote Link to comment Share on other sites More sharing options...
HauteHippie Posted November 28, 2007 Report Share Posted November 28, 2007 It should be. If it is on a sapphire crystal (yes, they also put it on true sapphire crystals in place of AR), an effective way to remove it should be using any abrasive-polishing paste (other than diamond paste!) petroleum-based, or mixed with petroleum. Btw, Cape Cod cloths are like that. This is because sapphire cannot get scratched or made foggy-looking by abrasives. This method is effective in removing true single-side AR coating (low temperature AR coating), so I suppose it should also remove the fake AR coating. If it is on a glass crystal, as in DemonSlayer's watch, don't use abrasives: glass would get damaged. I would try a soft microfiber cloth impregnated with some solvents, starting with acethone. Keeping the crystal sunken under petroleum for 2-3 days before removing the tint might help to do the cloth work easier. This is good advice. You might consider replacing the mineral crystal with a sapphire one. Sapphire is not as expensive as you might think, although for thick, large, domed crystals it can be. Still worth looking into. True AR coating is not as effective on a mineral substrate as on a sapphire substrate. This has to do with the index of refraction (IOR) and how the coating is optimized. Genuine sapphire's IOR is anisotropic based on wavelength, and also varies based on purity (quite a bit with our reps). Mineral (i.e. glass) crystals are far outside of sapphire's IOR range. So, when I submit a batch of 40 or so crystals to my coater I ask them to find an IOR midpoint for all the sapphire crystals in the run and optimize the coating based on that midpoint. This is clearly not optimal for the few mineral crystals in the run, but it is really the only method that makes sense for a group of crystals, the majority of which are sapphire. The result on the mineral crystals is less of a color hue and more reflectance off the coated surface than on the sapphire crystals. The optimal way to do it would be to separate sapphire crystals and mineral crystals into different AR runs and optimize the coatings for each. In this case the mineral crystals would perform better, but still not as well as the sapphire. Too much information, I am sure. Quote Link to comment Share on other sites More sharing options...
sssurfer Posted November 28, 2007 Report Share Posted November 28, 2007 Too much information, I am sure. Not at all, chief! This was great info indeed, thanks! I was just wondering about double-side AR coating on glass crystals. As in case of double-side AR the final scratch-resistance is that of the AR coating rather than that of the original matter, and as double-side AR coating is harder than glass but softer than sapphire, I was just thinking that double-side AR coating is an even better fit to glass than to sapphire. To put it shortly, about scratch-resistance double AR coating makes the glass better, and sapphire worse. I already had a double-side AR coating test performed on a [top quality] glass crystal, and the results were to my appointment. To my eyes, any loose in the AR effect and blueish nuance was completely acceptable. Now you said that an even better result may be achieved on glass, in case of a run for glass only! Do you think that, if there is interest enough on a run for double side AR on glass crystals, you would perform it? Quote Link to comment Share on other sites More sharing options...
HauteHippie Posted November 28, 2007 Report Share Posted November 28, 2007 Not at all, chief! This was great info indeed, thanks! I was just wondering about double-side AR coating on glass crystals. As in case of double-side AR the final scratch-resistance is that of the AR coating rather than that of the original matter, and as double-side AR coating is harder than glass but softer than sapphire, I was just thinking that double-side AR coating is an even better fit to glass than to sapphire. To put it shortly, about scratch-resistance double AR coating makes the glass better, and sapphire worse. I already had a double-side AR coating test performed on a [top quality] glass crystal, and the results were to my appointment. To my eyes, any loose in the AR effect and blueish nuance was completely acceptable. Now you said that an even better result may be achieved on glass, in case of a run for glass only! Do you think that, if there is interest enough on a run for double side AR on glass crystals, you would perform it? I am not sure that MIL-C-675 AR is more durable than glass... It could be, but I've never verified this. I put a Jimmy Fu crystal into one of my AR runs, and I could see a difference between it and the sapphire crystals in the run, but there was a definite improvement over no AR even with the sapphire-optimized coating applied. I will gladly do a glass-only AR run any time there is demand for it. FYI, I have now officially changed coating companies. The new company will be used for the upcoming double AR run in early December and for the forseeable future. Two very exciting developments are the following: full aperture coating (i.e. no lip marks), and a higher performance coating. Previously the coating I used produced an average reflectance of 1.25% across the visible spectrum, and less than 1% at the sweet spot (550 nm). The new coating is going to produce less than 0.5% reflectance across the entire visible spectrum which means the crystal disappearing act will be even more profound on double coated crystals. The only difference is going to be that instead of a subtle blue, the new coating is going to have an even more subtle (harder to see) violet tint. So it'll actually be more color neutral. The only time you really see the tint is under florescent lighting, and even then you almost have to be trying to see it - and if you take a trip into an AD, I think you'll find the same situation on gen watches. That is, you're not going to see the color of the AR very easily, but you're immediately going to see what looks like an invisible crystal due to lack of reflections! (Except of course on PAMs where they still only coat the interior) Quote Link to comment Share on other sites More sharing options...
sssurfer Posted November 28, 2007 Report Share Posted November 28, 2007 I am not sure that MIL-C-675 AR is more durable than glass... It could be, but I've never verified this.Well, B., just try and have not 20, but just 2, strokes with a rubber pumice eraser on a glass crystal then let me know. I will gladly do a glass-only AR run any time there is demand for it.Gret news again, B., thanks! I plan to gauge interest about it in a next future. The only contrary point I can foresee is that glass crystal reps are usually low-cost reps, so that owners might not be willing to invest 30% of the rep cost in order to "just" improve look and scratch resistance. Oh well, we'll see.... FYI,....Wow, chief, you got me excited! On my small experiences I came to conclude that a good double AR coating is the way to go even on PAMs. Fuck with the single-side AR accuracy! Our reps are not supposed to withstand a same hardwork as gens, so there's no point in having the outer crystal surface made of uncoated sapphire rather than AR coated... Quote Link to comment Share on other sites More sharing options...
HauteHippie Posted November 28, 2007 Report Share Posted November 28, 2007 Fuck with the single-side AR accuracy! LOL! I didn't know you also spoke French, M! Quote Link to comment Share on other sites More sharing options...
Pugwash Posted November 28, 2007 Report Share Posted November 28, 2007 My 111h ($110 version from Silix) has sapphire and light AR that actually reduces reflections. It's not impossible to do for cheap, apparently. Quote Link to comment Share on other sites More sharing options...
HauteHippie Posted November 28, 2007 Report Share Posted November 28, 2007 My 111h ($110 version from Silix) has sapphire and light AR that actually reduces reflections. Very little compared to a 111H (I or J now) at a PAM boutique. Its main purpose is to allow you to say "Look, my crystal is blue!" Quote Link to comment Share on other sites More sharing options...
Pugwash Posted November 28, 2007 Report Share Posted November 28, 2007 Very little compared to a 111H (I or J now) at a PAM boutique. Its main purpose is to allow you to say "Look, my crystal is blue!" I admit it's nowhere near genuine, but it's not blue-tinted. I didn't notice the AR until I had it next to Golfman's un-ARed PAM and it was obvious mine had far fewer reflections than his, even though both were sapphire. The AR is more for go than show, unusually. Quote Link to comment Share on other sites More sharing options...
DemonSlayer Posted November 28, 2007 Author Report Share Posted November 28, 2007 Was that $110 shipped @ pugwash? Quote Link to comment Share on other sites More sharing options...
TeeJay Posted November 28, 2007 Report Share Posted November 28, 2007 (edited) When I first took it out of the wrappings (and it was still inside one of the plastic case-shields) I actually thought the watch had a blue dial It wasn't untill I took it out completely and examined it properly, that I realized that wasn't so Edited November 28, 2007 by TeeJay Quote Link to comment Share on other sites More sharing options...
Pugwash Posted November 28, 2007 Report Share Posted November 28, 2007 Was that $110 shipped @ pugwash? In all honesty, I don't remember; It was over a year ago. Quote Link to comment Share on other sites More sharing options...
HauteHippie Posted November 29, 2007 Report Share Posted November 29, 2007 The retail price for a 111H crystal in sapphire is around $40 or so. That is, a generic domed sapphire crystal of appropriate thickness and diameter. So $110 is a great deal for a chunk of real sapphire that size with an entire watch wrapped around it. Quote Link to comment Share on other sites More sharing options...
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