Joe’s Threshold and Posterize offers an extended set of thresholding controls for Final Cut Pro. The basic effect transforms a clip into a two-color black and white image, changing between the two at a specified color value. This effect can be further modified by increasing the number of values (posterization) and replacing black and white with any color. Additionally, the filter can pre and post blur the filtered image to soften shapes or edges.
Example Images
Different gray sources will produce different results. For examples of how the different color channels affect black and white images, see Joe’s Simple Saturation.
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| Gray Source: | Full Color (Posterize) |
| Threshold: | 103 |
| Steps: | 2 |
| pre-blur: | None |
| post-blur: | None |
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| Gray Source: | Full Color (Posterize) |
| Threshold: | 91 |
| Steps: | 156 |
| Pre-Blur: | 5 |
| Post-Blur: | 1 |
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Applying a two-step threshold to a color image usually results in 6 colors plus black and white. This happens because the threshold applies to each color channel. Two values of Red, Green and Blue mix together to produce all of the primary and secondary colors and white and black (when all channels are full strength or completely off). Desaturating an image before thresholding results in a black and white image.
Thresholding by it’s nature produces hard edges which don’t translate well to video. Adding a post-blur can help soften the image and reduce edge-crawl and other video artifacts that result from sharp, high-contrast edges.
Controls
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Gray Source (Full Color (Posterize), Gray (Average), Luma, Red, Green, Blue)
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Determines how to desaturate the source image for thresholding or enables full color posterization.
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Threshold (1 - 255)
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Sets the pixel value at which to split the image into black and white.
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Steps (2 - 255)
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Sets the number of steps between black and white. The value is split evenly around the threshold point (based on the same principles as Joe’s Levels). This effect is somtimes called posterization, especially when the source image contains colors.
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Pre Blur (0 - 150)
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Applies a blur to the image before thresholding. This can help to smooth out extra detail, at high values it produces rounded shapes.
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Post Blur (0 - 150)
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Applies a blur to the image as the last step after thresholding. To anti-alias edges and reduce edge-crawl, use a value below 1. To access decimal amounts in Final Cut Pro sliders, hold down the shift key while dragging.
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Foreground, Background
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Sets the colors to use for thresholded images. If Gray Source is set to Full Color these settings are ignored.
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Transparent Color (Foreground, Background)
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Sets which color to make transparent. If Gray Source is set to Full Color this setting is ignored.
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Opacity (0 - 100)
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Sets the opacity of the color selected by Transparent Color.
Feeds