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Slow fade up is stepping with each frame?
Hello everybody,
I’m doing a very slow fade from black to my subject. This is for an ambient backdrop video, so the fade spans over 1 minute.
The problem I’m getting is that while previewing, one can see the levels of grey “stepping” instead of transitioning smoothly. It has the same look as if the black layer was running at a slower frame rate than the rest of my video (which is obviously not the case)If anyone can help I’d appreciate it. The desired effect is to be 100% black at frame 0, and to slowly & fluidly fade up over at least 1 min.
This “stepping” happens over multiple computers, within after effects & on the final rendered videos so it’s not a glitch, it may just be a limitation of the software. Any suggestions or workarounds?
I’m thinking it may be to do with the fact that I’m viewing the video on a computer monitor which is able to show more shades of black than a TV monitor?
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5 Replies
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Are you using a transition preset fade or are you keyframing the opacity of the clip from 0 to 100% over time? I would try the latter if you haven’t done so already. I’ve keyframed a fade up many times without the problem that you’re describing.
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Thanks for the quick reply, I’m keyframing the opacity of a black solid, which is on top of all my other layers.
I’ve done this type of “fade up” many, many times before and it has always looked OK. I think it’s the unusually long length of the fade that’s screwing me up this time around.
I’ve tried to eliminate all possible problems – I just put a red solid under the black layer (so that the comp should just be a simple slow fade from black to red) and the stepping is still happening. This means that the problem isn’t caused by my footage or whatever underneath.
There are no effects applied to my black layer, and this problem isn’t local to this specific project/machine.
It looks as though there are only a specific number of shades of black to fade through, and my frame count is larger than this particular number. Does that make sense?
I’ll try to up my bits-per-channel and see if I have any luck.
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For the record, I’ve added a very subtle “Add grain” adjustment layer, and the visual problem seems to have disappeared.
It means of course that I now need to have slight grain in my video, but it’s a welcome tradeoff. -
you’re probably running in to the limitations of 8 bpc color, similar to the banding that can be seen on subtle gradients/ramps. a fade from black to white has only 256 shades in 8 bpc color, 1 minute of video has 1800 frames, so there would be a stepping effect.
the noise trick you discovered should work. as should setting the comp to 16 bpc (16 bpc would have about 65,000 shades from black to white).
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
Also be aware that some effects are only 8-bit effects, so they may cause the banding/stepping of colors, even if rendered in 16-bit. “8-bit only” effects will have a yellow “!” triangle next to them in your effects pallet.
(To quickly switch to 16bit mode, option-click (mac) the word 8-bit at the bottom of your Projects window. )
Antifreeze Design
https://www.antifreezemotiongraphics.com
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