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Thread: Chroma - a laser color blender

  1. #81
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    There was nothing at wrong with my recommendations. Dan, you made it perfectly clear you preferred real world testing to prediction software and then attacked threads where Chroma was used as the basis for a recommendation. Whereas I can't argue with real world experience as being the best way, Chroma was a perfectly good tool for prediction and there were no insane colour concoctions as you put it. In fact I believe Chroma predicted 1:1:1 for 532:640/637:445, and what is the golden mix for those - 1:1:1! http://www.photonlexicon.com/forums/...ghlight=Chroma post #18

    From my memory, you also constantly spammed every Chroma thread with the fact that it was poo.

    I've yet to see any evidence that predictions generated by Chroma are in any way inaccurate. In fact the white balance provided by the inner triangle, of which I was the only person to point its existence out, seemed highly accurate. The white balance also accords perfectly well with what I see on the Kvant so before you start making wild accusations of insane colour concoctions, read back through the threads and get your facts right! It seems you have a selective memory!

  2. #82
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    I think you will like my references. I shall let you discuss your points now with yourself:



    Quote Originally Posted by White-Light View Post
    There was nothing at wrong with my recommendations.
    Quote below from: link
    Quote Originally Posted by White-Light View Post
    473nm gives very nice bright yellows

    ------------------------------------------------


    Quote Originally Posted by White-Light View Post
    Chroma was a perfectly good tool for prediction and there were no insane colour concoctions as you put it.
    Quote below from: link
    Quote Originally Posted by White-Light View Post
    1 W 445 blue will be dimmer than 100mw 532 green.

    ------------------------------------------------


    Quote Originally Posted by White-Light View Post
    I've yet to see any evidence that predictions generated by Chroma are in any way inaccurate.
    Quote below from: link
    Quote Originally Posted by White-Light View Post
    So for the diode to output yellow it has to be lasing at both red and green wavelengths simoultaneously. Whether or not you can separate the red out is another matter. Chroma predicts yes, but without having access to OPSL to try, its very difficult to say.

    ------------------------------------------------


    Quote Originally Posted by White-Light View Post
    In fact the white balance provided by the inner triangle, of which I was the only person to point its existence out, seemed highly accurate.
    Quote below from: link
    Quote Originally Posted by White-Light View Post
    To my mind this gives chroma a use in obtaining a white ablance. eg, want a warm reddy white, then plot for the red side of the triangle. Want a cool white, plot for the green side like Steve did or for the blue area for a more bluey white.

    I'm pretty sure that with such a wide area within the white triangle pretty much every colour temperature of white is covered.
    So, let me get this straight, you are saying hit any of the white bit in the CIE chart, and this produces a type of white?
    Wow; this is a groundbreaking revelation. It was a good job I was sitting down.


    ------------------------------------------------


    Quote Originally Posted by White-Light View Post
    The white balance also accords perfectly well with what I see on the Kvant so before you start making wild accusations of insane colour concoctions!
    Because they always get it right...
    http://www.synchrovision.co.uk/produ...canners-30kpps

    and

    - There is no such word as "can't" -
    - 60% of the time it works every time -

  3. #83
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    I stand by everything I said.

    The perceived luminosity of 445nm is less than 532nm watt for watt, that's a proven medical fact as the eye has a greater response to the green wavelength.

    Dark blue pulls down the lighter colours in mixes, it doesn't take a rocket scientist to work that out. Try with some paint at home, put 1 blob of white with 1 blob of light blue then do the same with 1 blob of white and 1 blob of dark blue and tell me the result with the dark blue isn't darker.

    The feint white triangle rather than the spot in the centre of chroma was something I brought to everyone's attention as previously everyone (including myself) had concentrated on the very small white spot in the centre.

    Although Kvant are fantastic projectors, Kvant traditionally have had a bias towards blue, even my 2.1W Kvant is slightly blue heavy and that's with only 1W blue and 680mw 637 & 500mw 532. If you're seriously suggesting that 4w 455nm can balance with only 600mw 640nm and 500mw 532nm to produce a perfect neutral white then I suggest you're dreaming.



  4. #84
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    Quote Originally Posted by White-Light View Post
    Dark blue pulls down the lighter colours in mixes, it doesn't take a rocket scientist to work that out. Try with some paint at home, put 1 blob of white with 1 blob of light blue then do the same with 1 blob of white and 1 blob of dark blue and tell me the result with the dark blue isn't darker
    Additive and subtractive colour issues aside for one moment:
    Quote Originally Posted by White-Light View Post
    I stand by everything I said.
    Then you are a fool.
    - There is no such word as "can't" -
    - 60% of the time it works every time -

  5. #85
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    Quote Originally Posted by White-Light View Post
    I stand by everything I said.
    Really?

    Quote Originally Posted by White-Light View Post
    473nm gives very nice bright yellows
    Discuss.

    Quote Originally Posted by White-Light View Post
    [IMG]http:/www.australianclimatemadness.com/wp-content/uploads/2011/11/flogging_dead_horse_what.jpg[/IMG]
    nice use of a pot and a kettle

    Rob
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
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    Quote Originally Posted by stanwax View Post
    Really?

    Discuss.
    Entirely.

    1. Whereas I respect both yours and Dan's experience, you can't argue with the laws of physics and medicine and they clearly state that the eye is more sensitive to green than blue.

    In fact Dan states he respects Tocket's Chroma, so just putting aside any past comments, and running some figures, chroma States:

    1 Watt 445 Blue: Luminosity 28.9531 lumens

    1 Watt 532 Green: Luminosity 604.3433 lumens

    Feel free to run the figures yourself.

    It also predicts the golden mix of 1:1:1 with 445 and 640nm.

    However, I concede that whilst with 445nm there is phenomena that occurs when its a pencil beam in that it appears to glow white not blue at its core and thus appears much brighter than expected, when you fan 445nm out into a wide fan side by side with a fan of 532 of the same power, the 445 is not as bright (luminous).

    So I see nothing wrong with the statement that 445nm blue is not as bright as 532 and all the established scientific evidence, physical, medical, mathematical and visual backs that up.


    2. As for colours, irrespective of whether its additive or subtractive if you take away or add dark blue to any light colour, then dark blue will have a larger influence on the colour of the mix produced than if you took away or added light blue.

    3. Specifically for yellow, its harder to explain other than to say 100% pure yellow is just red and green. However, lasers produce many millions of shades of many colours and so unless a yellow is 100% pure, it will contain an element of blue if only in a small quantity. Again dark blue will have more of an influence than light blue on the luminosity of a mix which is why I say that lighter colour mixes appear darker in a projector with 445nm in it when compared to one with 473nm in it. I'm also not the only person to have observed this. I believe some while ago Buffo said he had observed the same thing as did several others.
    Last edited by White-Light; 05-10-2012 at 09:41.

  7. #87
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    Quote Originally Posted by White-Light View Post
    1. Whereas I respect both yours and Dan's experience, you can't argue with the laws of physics and medicine and they clearly state that the eye is more sensitive to green than blue.

    In fact Dan states he respects Tocket's Chroma, so just putting aside any past comments, and running some figures, chroma States:

    1 Watt 445 Blue: Luminosity 28.9531 lumens

    1 Watt 532 Green: Luminosity 604.3433 lumens

    Feel free to run the figures yourself.
    This ratio might be accurate under photopic vision but is not at all true under scotopic vision.

    You're full of shit, and adding more significant figures does not make you any less full of shit.

  8. #88
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    Al Al Al, sit down and have a listen, and no butting in. Hear me out.

    Quote Originally Posted by White-Light View Post
    Feel free to run the figures yourself.
    err no thanks.

    Quote Originally Posted by White-Light View Post

    you can't argue with the laws of physics and medicine
    Yes you can.
    And being the kind person you are you have very thoughtfully pre-empted my line of thought and provided an example to make this an easy point to prove.

    Quote Originally Posted by White-Light View Post
    However, I concede that whilst with 445nm there is phenomena that occurs when its a pencil beam in that it appears to glow white not blue at its core
    We all know this is impossible. How can a blue beam from a [practically] single wavelength source appear to us to be white. Please demonstrate with that confounded program the groundbreaking revelation that a blue laser on its own makes white light. It cant. It cant because where it (the c program) falls down is that it only uses the physical and medical facts and omits one very important variable. That variable, which I suspect is as good as un-quantifiable, is the marvelous ability of the human brain to play tricks on us. So rather than actually being white we just perceive it that way.

    The fact is that within reason, you can pretty much stick any mix of red green and blue in the projector and without any other external reference, such as a perfectly balanced projector displaying white, we will swear blind that it can make white. Now I know what ya gonna say, you want to point out the faint http://dictionary.reference.com/browse/faint?s=t (as opposed to feint http://dictionary.reference.com/browse/feint?s=t) triangle that allows a range of mixes around that 'golden' centre area. Well I would bet all my lasers that the triangle does not reach out far enough. The reason, the un-quantifiable human brain variable.

    A practical example of this, may be demonstrated by my own blue green projectors. 1W each of 445 and 532nm meaning that there would be a very well defined range of colours available based on these wavelengths. With both lasers on full, the colour they produce is cyan. That’s a physical and medical fact. However with certain colour effects the brain interprets the contrasting shades and tells you that the cyan you can physically and medically prove is cyan, appears to be white. Choma please show how this is possible. Its a rhetorical question because I know you cant. With you amazing ability to show relative luminosity and blends of colours based on power and wavelength you can’t!

    Not convinced?

    Another example then.

    Same projector and a colour effect that I think you are gonna like as its cyan (100% green and blue) at the edges and green (100% green) in the middle. Stand in a not that dark environment and observe. You would swear its white at the tips and yellow in the middle. Yes yellow! It cant be! That’s impossible I hear you cry. Yes its impossible but it happens to be true, a fact of life not physics or medicine. Once again I ask the same question, demonstrate this in that program (cant bring myself to say its name again - was tough enough the first time!). And here’s another thing, you may see this yellow as more or less yellow than I do. Luminosity cant explain that.

    And that’s the point, we can never say what different brains, no matter how few synapses may be online, will tell the individual what they are seeing.

    This is why I have never had a desire or inclination to download or use software to tell me what I should be seeing as my brain will override this data in any case.

    Therefore I conclude that for real life practical examples, no matter how many times you shout about it, no matter how proven the physical and medical facts are or how well written the software may be, without taking into account the impossible brain variable, the output of this software has no practical value. I prefer to use my knowledge and experience to spec real world projectors without referring to the nonsense from this program.

    So now I respectfully ask you to move away from the flogged to death high horse until you have knowledge and or experience to back up the garbage you pedal.

    Oh one more thing – I will go and get me some paint – but not to do your test, rather to apply it to a surface so I can watch it dry.

    Rob
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
    -----------------------------------------------------------------------------------------------
    Laserists do it by the nanometre.

    Stanwax Laser is a Corporate Member of Ilda

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  9. #89
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    Quote Originally Posted by j4cbo View Post
    This ratio might be accurate under photopic vision but is not at all true under scotopic vision.
    Well at least someone has said something that actually presents a reasoned argument!

    The eyes sensitivity to blue varies according to the ambient lighting and there's no argument from me there. But did I ever specify that I was putting forwards the above luminosity figures based on total darkness?

    No because from the figures chroma produces I imagine chroma works in the photopic when making luminosity predictions looking at those values and in the scotopic when making colour predictions, although you'd have to ask Tocket for confirmation on that one, so it may well be those luminosity figures would be much closer under scotopic loading which is why when chroma makes colour predictions it recommends close to 1:1:1 with 445 and 640 in the mix even though on luminosity values they are a world apart. At the end of the day , its like any tool, it depends on how you use it. My recommendations were made on white balance prediction not luminosity.

    ..and btw just to be absolutely clear my understanding is scotopic vision only occurs in almost absolute darkness, that is when the ambient light is below 0.034 lm/m²/0.034 cd/m2 equivalent to a night time with no moon.

    Even then the peak sensitivity is 507nm / 508nm which is still slightly closer to 532 than 445.

    It's far more likely that in many nightclubs vision would be mesopic depending on the ambient light levels. Some I've been to are probably even photopic where LED dance floors or large numbers of other fixtures are in use at the same time eg moving heads or where there's eg bright bar lighting just off the dance floor. Many others are going to be mesopic.

    Quote Originally Posted by j4cbo View Post
    You're full of shit, and adding more significant figures does not make you any less full of shit.
    There's absolutely no need to be an arse hole especially when you quote scotopic as the definitive reason when in many situations your assertion is incorrect as with ambient lighting it's more likely mesopic.

    @ Rob, I'm quite well aware that its impossible for blue to turn white so again no argument from me that this phenomena is probably down to the brains interpretation of the level of saturation of blue you see in the pencil beam. I am actually well aware that you can produce an apparent white from just two colours and yes again the brains interpretation of this is probably the only explanation.

    As for chroma, its only a prediction tool and no-one ever said it was perfect. However its a lot better than taking a wild guess at the required amounts of each wavelength required to make a balanced white projector especially for the novice builder as its far cheaper than trial and error. To that end it does appear to correctly predict white balances with some degree of accuracy which is why I've always given Tocket credit for his utility.
    Last edited by White-Light; 05-10-2012 at 15:46.

  10. #90
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    Quote Originally Posted by White-Light View Post
    As for chroma, ...its a lot better than taking a wild guess at the required amounts of each wavelength required to make a balanced white projector especially for the novice builder as its far cheaper than trial and error.
    Argghhh... and we go round again...!

    Before this thread goes any further into the chasms of hilarity/stupidity/pejoratives/groundbreaking-colour-theory (delete as appropriate);
    let's wheel out the horse again for light relief:

    http://www.youtube.com/watch?v=-YivhhrYmRY&feature=fvst
    - There is no such word as "can't" -
    - 60% of the time it works every time -

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