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rasputin

TIP: Avoiding artifacts in FACEBOOK

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Hey guys,

I don't know if you've encountered this problem when seeking to share your C4D renders on Facebook:    Facebook's image publishing algorithm features a rather harsh compression standard.   (I guess they have to use it,  given the bazillions of images they are forced to store on their servers everyday.)  In most images you publish,    Facebook is going to make them come out with nasty artifacting,   especially all sorts of ugliness around your sharp edges.    It also tends to make your fields of solid color full of bad artifacting,    and  will make your color gradients come out with ugly banding.   The more "toon-y" and less photorealistic  is your image,  the worse will be the artifacting.   I've had a couple  of my image posts almost completely ruined by Facebook's compression,  which bummed me out plenty. 

Even if your render is already compressed and low-filesize---   as with a JPG---    Facebook will even compress it further.    :angry:

Well,   I think I've discovered a bit of a workaround to making your image posts to Facebook look better,   a bit closer to how they originally looked when you first rendered them in C4D.

  • Export your C4D render as a 16-bit PNG.

 

  • Import your C4D render into Photoshop,    then choose the ADD NOISE filter.    Make sure the filter is set to Gaussian and Monochrome.     Then you want to dial in a Noise setting that is extremely subtle,  like 0.5%   or 0.6%          The resulting noise should be extremely subtle,  and not change your C4D picture unduly.     You can always  FADE the effect under EDIT after application,  until the noise is almost imperceptible.   I don't know why---   someone clever here will perhaps know---    but the slight noise added to the image completely "short-circuits"  Facebook's compression algorithm,  and your image will be posted with very little... almost no...   banding and artifacting  (which were far worse,  visually,   than the slight Noise you're adding)


I also notice that Facebook tends to post your image slightly cooler and slightly less saturated than it appeared when first rendered.     :angry:
 

  • You can prep for this by making your image 2-3 degrees warmer in Photoshop under HUE/SATURATION,   and you can use 2-3 degrees of Vibrance added,  before you post to Facebook.


With these steps--   admittedly,  they are a workaround,  not a cure---    your image in Facebook should look closer to your original artistic vision.

 

ras

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this technique with the noise is also used for moving images in compositing. you face the same issues with banding and such if you export to mp4 with h264 compression. to the reason WHY that works: compression algorithms like jpg or h264 look at similar pixels within a certain radius and only store an average, not the information for each pixel anymore. furthermore they also take those blocks of a few pixels and compare them to the other blocks around it and if those are very similar they seem to not store their position within that cluster and seem to randomize them. you can actually see how compression works if you save out a jpg with pretty low quality settings. zoom in and observe. now if you add noise, the algorithm can't find that much similar pixels, resulting in smaller clusters and more precise output after compression. this also results in much bigger file sizes of course.

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