Do we have a guide as to how far tint shifts based on the tint you start with before dedoming? I know generally speaking that dedoming will move you to a warmer tint, but how far? What is the "best" cool white tint to start with so as to end up near a nice neutral white tint (i.e. 4C tint)? Start with a 1C? 1A? Or is it not this simple?
-Garry
I saw a nice post of maybe 3 different tints, and their resulting de-domed tints - not sure where this was. I like the 0D and 1A's de-domed - 1A turns neutral but not too much yellow - much like a 3C or little less. 1C's definite more yellow, I'd say more so than a 3C. I accidentally de-domed a 3C and wow - ton of yellow but looked nothing like the T3 6A1 and T4 warms I've seen - the de-domed 3C was much more yellow than the warm tints, in fact the warm tints seem to me to be more of a true pale white while the 3C is more yellow.
Well thanks to RaceR86 i know that de doming of cold white emitter(6500) upper neutral white color appears(around 4800) which has little greenish tint visible in aspheric and not so visible in reflector. This de-domed tint looks much better to me than cool white but don’t ask me; you decide.
Guys if you are not familiar with tint colors it looks something like this:
I would say its beneficial to start with 1A/1D instead of 1B/C.
On the tint chart, most emitters seem to end up 1300-2100K to the left, and then some up (towards the green/yellow spectrum) You will not end up with anything as nice as a 4C no matter where you start in the CW range.. A 2A would probably get you "close" to a 4C in terms of temperature. But it could still not compete in color rendition or color tone IMO. I have not measured this stuff, so I dont have hard factual numbers. I have seen texaspyro show some stuff on temperature change, but I have never seen any numbers on color tone.
Luminarium, your are learning. :) Although the pictures you are showing are for describing temperature (kelvin), not hue.
I’ve found through trial and ONE error (XR-E) that dedoming an XP-G2 R5 2B (CW) on a noctigon:
http://intl-outdoor.com/noctigon-xp20-mcpcb-cree-xpg2-r5-2b-led-p-723.html
:and put in a DD zoomie gave me a really sharp die image, and it retained a great amount of ‘cool whiteness’…
But, when I dedomed another XP-G2 R5 2B (CW), this time on a alu star:
http://intl-outdoor.com/cree-xpg2-r5-2b-led-20mm-mcpcb-p-705.html
:and again mounted in an identical DD zoomie, I got the green tint… everso slight on zoomed in mode (again a nice sharp die image), but quite visible on flood!
Clearly the Noctigon copper base helps immensely.
Cheers all
Rob
RaceR86 - that's what I was thinking - de-doming would take you 3-4 cells over to the right, and maybe 1 up on this chart: http://flashlightwiki.com/images/c/cb/Ansi-white.jpg. Don't think your link is working, not sure if the ANSI white chart is what you meant.
Link works for me.
-Garry
Yesterday tried my first gasoline dedome, in EU unleaded 95 gas (here called "benzina", if anybody cares).
Worked like a dream, both emitters came out of the overnight bath clean like the dome was never been there, wires area too! GREAT!
But clearly I underestimated the color shift: on noctigon XML2 T6 C3 became so yellow it looks like those french car headlights from the early eighties... 
And on octigon XPG2 R5 B2 went slightly better but has a definite green hue.
Now ordered XML2 U2 A1, hope the tint remain better...
Did my first dedoming for a TR-J19 build. Soaked the emitters in gasoline overnight and cleaned them up this morning. Tested them and they all work. :)
did the gasoline affect the gold coating on the back?
Not that I noticed. They look perfect. I was worried about the phosphor layer before dunking them but it is solid on all of them.
Isopropyl alcohol should be used to clean em up - I squirt it directly on the phosphor giving the whole star a god shower, then perfect. Btw, I sand down the nickel/gold on the backside using 2000 or 2500 grit - they come stock pretty smooth but just to be sure to remove small burrs on the edges... Soo much easier/better than SinkPAD's.
My second attempt went quite well. The dome didn’t fall ott, but it has small cracks in the silicone, so i thought it is ready to rock.
Then i easily popped off the dome with a toothpick, and let it dry. There is some silicone near the bond wires, but the wires are embeddeded, and didn’t dare to remove.
IMHO it will affect the beam pattern in a reflector light, but i won’t try to remove that goo. Maybe with an xm-l2 which has fewer bond wires it could be done.
EDIT: 118 kCD throw, not bad 
Could be better with xm-l2 
Good job!
Why do I believe the LED seal is actually a repurposed can of high temp silicon based clearcoat?
Just marked up 2x?
Chemicals safe to use on Cree emitters without discoloring them
http://www.cree.com/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/XLamp%20Application%20Notes/XLamp_Chemical_Comp.pdf
Because you're hopelessly jaded, probably don't believe in the Great Pumpkin, either. 
So lets say TK61 is 170kcd on stock. With dedome it should be around 300.000cd right?
I got around 280/300kcd on mine @10 meters, or 2800 lux….is this result good? mind you, no current bump yet.
LEDseal dries just like clear RTV silicone, clearcoat most definitely is not even remotely similar, except that both are clear and come in an aerosol can.
Generally, you should get double the kcd, so should be bout 340. If you are getting less, probably needs more focus tweaking. Just be sure you do your before/after measurements same way - same distance for example. Of course assumes same amps, but a TK61 should hold the same amps.
Just attempted my first dedome. Dunked my XML in gasoline for about 16 hours, then the dome just fell off as I was removing the star from the gas. I was really pleased with myself till I inspected the led and noticed the bond wires floated off with the dome. not sure what I did wrong…
