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“Add” generates a black border – 32-bit linear
When using 32-bit linear workflow and using blending mode “Add”, I get black borders around the video that was supposed to blend. Any ideas?
Please have a look at the attached screenshot, or have a look at it here: https://www.dropbox.com/s/m3ql9rawnxwz6st/black_border_32_bit_linear.jpg?dl=0
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2 Replies
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If you add a negative value to a positive value you will get a subtraction.
The chances are that the element you are trying to add has negative values (in the deep blacks at the edges), i.e, pixels that are below zero.
Hence the darkening effect.
Simon Ubsdell
tokyo productions
hawaiki -
[Simon Ubsdell] “If you add a negative value to a positive value you will get a subtraction.”
Indeed, this is one of the ways that 32bpc floating point works differently than 8bpc/16bpc.
The Levels effect has an option to clamp black and/or white. Add Levels, leave the “normal” Levels controls (the histogram, inputs, gamma and outputs) alone, and change “Clip to output black” from its default “Off for 32bpc color” to “On.”
Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive | RenderBreak [blog] | Profile [LinkedIn]
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