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Thread: Make lights in preview brighter

  1. #11
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    Default Re: Make lights in preview brighter

    Quote Originally Posted by jchuchla View Post
    No, it shouldn't be flat. If it were flat at 60, then the output will always be 60. For whatever value you send it from the effect. If you want it to be in a range of 0-60, it should start at 0 on the left, and go up to 60 on the right. The X axis is the value going into the curve, the y axis is what it will be on the output.
    Cool my thinking was correct but you have to set dimming curve with a low and a high value ?


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  2. #12
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    Default Re: Make lights in preview brighter

    Quote Originally Posted by wilmar View Post
    Cool my thinking was correct but you have to set dimming curve with a low and a high value ?


    Sent from my iPhone using Tapatalk
    Yes, if you want a linear response, then yes you need to set the low and high, and the low and high need to be at the left and right sides of the graph.

    However, that's not the only use for a dimming curve, so it's not always that simple. For example: below is a curve I use for AC string LEDs for my minitrees. They don't light up at all from 1-14. They first start glowing at 15% So I have the bottom end of the curve set to 14%.
    Capture.PNG

    Here's an example of a gamma curve that might be used with a video type prop
    Capture.PNG

    Here's an example of a gamma curve with a reduced 60% brightness.
    Capture.PNG

  3. #13
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    Default Re: Make lights in preview brighter

    Just went and thru a curve ball at me the gamma lol I havenít made it that far yet Iím still in kindergarten.


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  4. #14
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    Default Re: Make lights in preview brighter

    The Gamma curves can be generated as well so you don't have to take the time to draw out all the dots. Really anything that can be drawn with a math equation. But lets stick to the Gamma example. On the Curve Editor screen there is a button labeled f(x) Curve. It will bring up a dialog to enter the math equation. There is an example there for the Gamma curve.

    Pow(x/100, 2.8) * 100 +.5

    That will draw a curve similar to the second example Jon showed. If you want to reduce the overall output with a Gamma like Jon's third example, the formula gets changed to the following.

    Pow(x/100, 2.8) * 60 +.5

    Changing the multiply value from 100 to your max out brightness will alter the range of the Gamma. Our Pixel LEDS are very linear in how they apply brightness, but our eyes don't see it that way, so applying a Gamma curve to more aggressively reduce the brightness gives a more natural look to our eyes.

    Here is a pretty good article that explains it if you are interested.

    https://learn.adafruit.com/led-trick...tion/the-issue

  5. #15
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    Default Re: Make lights in preview brighter

    Read the article... helped me understand a little bit. Still not sure how the gamma curve applies vs linear when it comes to overall brightness, but I don't need to understand; I certainly trust ya'll on this.

    Thank you for the detailed explanations.

    The conclusion I reached is I have been doing overall brightness the really time consuming way for years!
    Last edited by Popo-B-Trippin; 01-11-2020 at 01:14 PM.

  6. #16
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    Default Re: Make lights in preview brighter

    So I'm trying to apply the newly discovered dimming curves (newly discovered by me anyway)... What is the exact process/order to do this? I know it has to be done before the item is mapped to a controller. Can it be done after the color filter is applied or does it need to be before that? Please dumb it down for me.

    Thanks!

    Chris

  7. #17
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    Default Re: Make lights in preview brighter

    For general dimming you should put it before the breakdown filter. That provides even dimming across all the colors and is the most efficient in performance. If you need to adjust color balance then you can put it after the breakdown and you will end up with dimming control on each of the breakdown colors. In normal RGB pixels you can just color balance by favoring one color over others.

    As far as the curve itself, you should link it to a library curve so you can come back later and edit the curve to update the behavior without having to overlay or repatch it. I generally use a gamma style curve on my pixels that help with the linearity of how the eye perceives the dimming. You can generate those curves with the function generator in the Curve editor. There is an example formula there to build them in a simple way. I think that has been covered in other threads, but let me know if you need more info on that concept.

    Here is a example that is 80% brightness and using a gamma curve.

    Gamma.PNG
    Last edited by jeffu231; 03-20-2020 at 10:40 PM.

  8. #18
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    Default Re: Make lights in preview brighter

    That's what I needed... just the order to do things. Thanks, Jeff!

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