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Thread: colors not right

  1. #1
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    Default colors not right

    I know this is a very general question but since I am using Vixen, I figured I would ask here...

    Should I not be using RGB codes for pixel lights?

    Sorry if this question has been asked a few times before, I just couldn't find an answer. I tried to Google it but did not find any relevant information with the keywords I was using.

    So this is my first year using pixel lights. I have spent over 40 hours on my Christmas sequence and decided to make one for Halloween to test them out before the season starts. Today was the first time I ever used my pixels and was greeted by some unwanted results.

    I realized that pretty much all my colors were wrong. The orange is yellow and purple was pink. I tried playing with brightness making it a little better but still just wrong. In the preview window everything is perfect. So I was wondering if I was really doing something wrong or is this completely normal and I must adjust the colors until I get them right. I'm kinda hoping there is a setting I missed because there are lots of colors for my xmas sequence which are all wrong... This Halloween one is pretty simple.


    If it makes a difference, I am using Vixen 3.4 with WS2811 pixels purchased from Ray Wu and a Falcon F16 controller.

  2. #2
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    Default Re: colors not right

    You likely need to change your color order. Different string types will not always expect color info to be delivered in the same order. Put together a simple sequence to cycle red, Green, blue and white and see if your pixels light up those colors in the correct order. If not, adjust the order in color handling in Vixen.

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  3. #3
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    Default Re: colors not right

    Bullet Nodes are typically RGB. My WS2812 strips were BRG and BGR. WS2811 strips were GBR.

    You need to set the color handling and patching based on the types of strips you are using. Here is how to find out.

    Create a sequence that has white for 5 seconds then Red for 5 seconds then Green for 5 seconds then Blue for 5 seconds.
    When that runs, record the order in which the strip lights. That is the type of strip you have. Adjust your patching or your controller settings to match.


    2019 - Just moved into a new home (yet another change of plans). Will be dim but not dark. Too much to do at the new place to leave time for a show.
    https://www.youtube.com/channel/UCyX...ttrsZNARkUce0Q

  4. #4
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    Default Re: colors not right

    What youíre describing isnít a color order issue. Youíre driving the right colors. Just in the wrong proportions.

    Purple and pink are basically the same color. One is just whiter than the other. same with orange and yellow.

    This is where gamma curves come into play. The dimming values are linear. And LEDs respond very linearly. Visual perception on the other hand is not at all linear. Your eyes are far more sensitive to changes in levels at the lower end than at the higher end. Your graphics system in the PC adds a gamma curve to correct for this on your monitor. Thereís no such automatic processing for the lights. You can certainly apply one though. You can do it in vixen by adding a gamma curve with a dimming curve in patching. Some controllers give an option to apply gamma curves for you at the controller level. The reason we donít automatically do this for you is that it comes with a penalty on lights. All lighting protocols and most pixels only support 8 bits per channel. Which means you have an 8bit per color color depth. When you apply a gamma curve you significantly cut down your potential color palette and dimming smoothness. In other words, if you start with 255 steps from full off to full on, you may have less than 100 after applying a dimming curve. This isnít as much of an issue with PC monitors where your color depth is much greater. Thatís why itís applied by default there.


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  5. #5
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    Default Re: colors not right

    Quote Originally Posted by jchuchla View Post
    What you’re describing isn’t a color order issue. You’re driving the right colors. Just in the wrong proportions.

    Purple and pink are basically the same color. One is just whiter than the other. same with orange and yellow.

    This is where gamma curves come into play. The dimming values are linear. And LEDs respond very linearly. Visual perception on the other hand is not at all linear. Your eyes are far more sensitive to changes in levels at the lower end than at the higher end. Your graphics system in the PC adds a gamma curve to correct for this on your monitor. There’s no such automatic processing for the lights. You can certainly apply one though. You can do it in vixen by adding a gamma curve with a dimming curve in patching. Some controllers give an option to apply gamma curves for you at the controller level. The reason we don’t automatically do this for you is that it comes with a penalty on lights. All lighting protocols and most pixels only support 8 bits per channel. Which means you have an 8bit per color color depth. When you apply a gamma curve you significantly cut down your potential color palette and dimming smoothness. In other words, if you start with 255 steps from full off to full on, you may have less than 100 after applying a dimming curve. This isn’t as much of an issue with PC monitors where your color depth is much greater. That’s why it’s applied by default there.


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    This is exactly the Info I was looking for. I saw the explanations for this and the resolution on other sites... But they were all talking about Arduino and having to add a piece of code to the sketch to compensate, which does not really work for our application. I didn't know how exactly to approach it. I've seen a graph that illustrates what you are describing. The actual led curve is a straight 45 degree line accross the chart, but the human eye on the same chart has a bulge in the middle. People were compensating for that by basically introducing a mirror opposite curve so that the net result should cancel each other out and give the human eye a linear curve that matches the led one. I'm just not sure how to do this without crippling the dimming

  6. #6
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    Default Re: colors not right

    There is a f(x) function in the dimming curve setup to be able to generate the curve. The example formula in that dialog is what you generally want. Yo can replace the 100 value in that formula for the max value you want on the dimming. So if you want a basic gamma curve with 70% max brightness, change the 100 to 70. You can experiment with that without the pain of having to specifically draw it.

  7. #7
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    Default Re: colors not right

    Quote Originally Posted by jchuchla View Post
    What you’re describing isn’t a color order issue. You’re driving the right colors. Just in the wrong proportions.

    Purple and pink are basically the same color. One is just whiter than the other. same with orange and yellow.

    This is where gamma curves come into play. The dimming values are linear. And LEDs respond very linearly. Visual perception on the other hand is not at all linear. Your eyes are far more sensitive to changes in levels at the lower end than at the higher end. Your graphics system in the PC adds a gamma curve to correct for this on your monitor. There’s no such automatic processing for the lights. You can certainly apply one though. You can do it in vixen by adding a gamma curve with a dimming curve in patching. Some controllers give an option to apply gamma curves for you at the controller level. The reason we don’t automatically do this for you is that it comes with a penalty on lights. All lighting protocols and most pixels only support 8 bits per channel. Which means you have an 8bit per color color depth. When you apply a gamma curve you significantly cut down your potential color palette and dimming smoothness. In other words, if you start with 255 steps from full off to full on, you may have less than 100 after applying a dimming curve. This isn’t as much of an issue with PC monitors where your color depth is much greater. That’s why it’s applied by default there.


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    Thank you very much for this very knowledgeable response. It all makes complete sense now.

    I did what the first two responses said but did not work or made things worse. I did not understand that the colors were actually the same but in different levels. Since playing with gamma curves seems like something I would want to avoid on my first year I decided to make a whole strip with 30 shades of orange and purple. From light all the way to very dark. It so happens that the colors I wanted are in the "very dark" side of things which is confusing to me but makes sense after I read what you said. At this point I don't even look at the preview window anymore. I will keep a permanent 50 node string just for testing, which I should of done before...

    Thank you all for the nice support!

  8. #8
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    Default Re: colors not right

    may very well be the curves. but make sure you got RGB order correct before you play with curves.
    see if they light up red when you tell them to light up red, same with G & B

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