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Motion 5's project-level alpha compositing wrong?

679 Views 5 Replies Latest reply: Dec 27, 2012 3:12 PM by zpincus RSS
zpincus Calculating status...
Currently Being Moderated
Dec 21, 2012 4:23 PM

Hi all,


I'm a very new Motion 5 user, and I am somewhat surprised by the color/alpha rendering and really aggressive antialiasing I am seeing in Motion. (I'm using the latest version: 5.0.6.)


Anyhow, to illustrate the issues I've been seeing, I made a simple test PDF in Illustrator and then exported it in a series of ways, which are illustrated below. (Though things look the same if I make the rectangles directly in Motion with the same colors...)


(1) PDF exported via Illustrator it to a PNG on a solid white background.


(2) I then imported this PDF into Motion and then exported a single frame as a PNG over a transparent background, which I then composited onto a solid white background in Photoshop.


(3) Then, I changed the background in the project properties to "Solid" and exported the a frame that way, thus letting Motion do the compositing onto the white background.


(4) Finally, I tried selecting the "Use Background Color" checkbox in the properties of the PDF media which causes the PDF to be composited onto a white background before any further processing happens in motion.


Note first that the text rendering is VERY VERY fuzzy from Motion vs. Illustrator (or Photoshop, where I added the white overlay text). Is there a way to tell Motion to antialias less aggressively?


Next, note that the alpha-compositing is VERY different when Motion composits the PDF against a white project background (case 3) versus all the other cases. The transparence is much more transparent looking!! This is versus how Photoshop or Illustrator composits 60% opacity against white (cases 1 and 2), or even how Motion does it on a media-specific case (rather than when compositing onto a solid project background), which is case 4. Has anyone else noticed this??


Finally, note how the color rendering intent changes depending on how the compositing was done, which is also pretty surprising.


Is there any way to control any of this? Is this some kind of bug? Or am I not understanding what to expect here? In particular, the fact that Motion seems to to do alpha-compositing wrong on the project background seems really problematic. Color rendering is an iffy thing to expect perfection from, and the soft antialiasing might be a design/aesthetic choice, but the compositing differences don't seem right.


Anyone have any thoughts?




test-illustrator copy.pngtest-transparent-PScomp copy.pngtest-solid copy.pngtest-solid-media-bg copy.png

  • fox_m Level 4 Level 4 (3,335 points)
    Currently Being Moderated
    Dec 21, 2012 10:52 PM (in response to zpincus)

    Sorry if I come across like an idiot — I didn't actually read your message in its entirety — just recognize the complaint.


    Exporting from Motion is *different* than creating an FCPX template. All templates are always treated as if they are rendered with "Best" settings.  When you export: you need to manually set all that.


    There are two ways.


    1) Setting the Canvas Render settings (from the Render menu -- but depending on your project, Best can drag performance more often than not)


    2) when you export, select the Render option in the export dialog.


    These are the default settings...


    Screen Shot 2012-12-22 at 12.28.00 AM.png


    If you left your canvas settings at Normal, then you can override those settings here. (Normal is always going to be a little "soft" when exporting.)


    Personally, I think it's better to uncheck Premuliply alpha (I have NO idea why this is on by default!)  What that does is take whatever your project background color setting is for the canvas (even though it's all alpha!) and blends it with the color/alpha  of  pixels being "blended"... it's designed to "aid" anti-aliasing as long as you know what kind of (similar) background you will be matching the graphic/video with elsewhere.  The premultiply  affected your export with a white project background creating that washed out look.


    Set the Render quality to Best or Custom (there are extra text controls in the Custom dialog that pops up). I think the "fully optioned" custom setting is the same as Best anyway, so ...


    [Fields is useless for anything other than interlaced video... do not know why they are checked by default (check the canvas setting for the defaults) -- but I don't think it makes any difference for stills -- same with Motion Blur and Frame Blending.]


    These settings should sharpen up your exports considerably (and correct the coloring).

  • fox_m Level 4 Level 4 (3,335 points)
    Currently Being Moderated
    Dec 23, 2012 2:56 PM (in response to zpincus)

    You're absolutely right -- Motion is getting it wrong... with Motion objects. Motion seems to be importing and displaying Photoshop generated semi-transparent PNGs *more* properly (detectable alpha range in a test gradient was from 10.6% to about 85%). I tested a gradient in Motion, and it's pretty much opaque for about 20-24% of the object, then goes down to -- what you said -- about 74/75% opacity *through* the mid section, then tapers off rather quickly, so that about 15% of the object is totally transparent.  The photoshop gradient is "evenly gradient" throughout the range...


    I don't think Motion is as concerned about the "rules" as getting by "optically" or "visually" and quickly -- as quickly as possible (an optimization -- I'll bet if you ask a Motion engineer, they would say it was a "feature"). For most things "in motion" (moving), most people aren't really going to notice that critically.


    If it is terribly important (and I'm not questioning that it is), you can adjust the opacity values in an object to more correctly reflect your intention.


    Add a Filters > Color Correction > Levels to the object. In the inspector, turn down the disclosure triangle next to the RGB Histogram. Then turn down the Opacity disclosure triangle.


    There are two properties you will want to adjust: White In and White Out.  I find if you set the White In to about 0.8 (~ 80%) and the White Out to 0.74 - 0.78 (~ 75%), you can adjust the transparency (alpha channel) down to the values you want (if you are using a gradient or multiple semi-transparent objects within a group.) I thought about using just the Gamma (for solids -- this won't work for gradients) but I don't know how that would affect any exports for use in an application like Photoshop (simply did not test it.) Since I stated that the gradient created in Motion basically "falls off" at around 15%, you may wish to adjust the Black In and Out parameters as well. Truth is: you can fiddle with all the Opacity parameters to adjust the "spread" of opacity throughout the range (including Mix, which is global, if you need "smoothing"); for most objects, the White In and Out will be the shortest cut.




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