masking out with tricky lighting
by Ignacio Triana
on
Jul 3, 2007 at 12:38:17 pm
hello, i have a video project where i shot a character surrounded by people spinning fire balls. during the shoot, i had them wear all black so they would not be seen so much.
due to the final lighting (only by the fire), you still see them conspicuously in the footage when the glow from the flame ( a tricky light as it glows and fades pretty far) gets near them or their arms, pants, etc.
i'm not trying to cut them out entirely, but would like to cut down on the odd appearances here and there in closeups.
it seems there are certain things to my advantage, and others not.
what i have done thus far in after effects:
-animated masks on adjustment layers that have luma key (set to key out brighter), changed the feather and opacity levels for when the flame gets close, ie details are really bright that i don't want.
when i set luma key to "....brighter", even at 0 it keys out everything. that's how faint their image is at times, which seems good.
i haven't gotten into setting keyframes for different transfer modes, cause it seems that the luma key function cancels out any real difference between these.
it has been a tedious frame-by-frame endeavor at this point, which i'm fine with, but i feel like their could be more options that i'm not aware of and was hoping anyone here could give some recommendations.
i've attached a url for an image from the sequence where i circled (yellow) the people i'm trying to extract, fade, make less apparent, etc.
Re: masking out with tricky lighting by Dave LaRonde on Jul 3, 2007 at 1:04:25 pm
[Ignacio Triana]"I haven't gotten into setting keyframes for different transfer modes, cause it seems that the luma key function cancels out any real difference between these."
You can only have ONE transfer mode active on any layer. There are no keyframes for transfer modes. If you want more than one transfer mode for a layer, you must duplicate layers, assign a different transfer mode to each duplicated layer, and either animate layer opacities, modify layer in and out points, or split layers.
You may also want to animate feathered masks on the footage layer to get rid of the light spill.
Re: masking out with tricky lighting by moldyboot on Jul 3, 2007 at 1:14:22 pm
i do think duplicating the layer and setting the upper layer to a trnasfer mode of multiply or one of the burn modes would help dim the people. you might try a little blur and a levels or curves adjust to that layer too.
if you lose some of the glow on the fire, you can always add that back later.
Re: masking out with tricky lighting by moldyboot on Jul 3, 2007 at 2:11:16 pm
try dragging your footage in to a new comp, then duplicate and set the transfer mode, try a few under the mulitply mode. then assess how close you are to what you want. try bluring the upper layer a little, maybe adjust levels of curves some too if you need to darken the darker areas or lighten up the areas you don't want to effect.
then if you want to focus in on specific areas, duplicate the upper layer and try using masksto issolate those areas, adjust feathering and opacity as needed to help blend.
Re: masking out with tricky lighting by Ignacio Triana on Jul 3, 2007 at 3:23:30 pm
duplicating the layer and using multiply as a transfer mode definitely seems to help.
i'm not so handy with adjusting levels in terms of something this dim. it's hard for me to notice any difference until it's too much and then i can't find an in-between.
i searched the cow for tutorials on this tool, but nothing terribly comprehensive it seems.
does anyone have any recommendations for someone like me who needs a firm grasp on adjusting levels and curves in terms of tutorials and such?
Re: masking out with tricky lighting by Ignacio Triana on Jul 3, 2007 at 3:23:34 pm
duplicating the layer and using multiply as a transfer mode definitely seems to help.
i'm not so handy with adjusting levels in terms of something this dim. it's hard for me to notice any difference until it's too much and then i can't find an in-between.
i searched the cow for tutorials on this tool, but nothing terribly comprehensive it seems.
does anyone have any recommendations for someone like me who needs a firm grasp on adjusting levels and curves in terms of tutorials and such?
Re: masking out with tricky lighting by Dave LaRonde on Jul 3, 2007 at 3:45:40 pm
[Ignacio Triana]"does anyone have any recommendations for someone like me who needs a firm grasp on adjusting levels and curves in terms of tutorials and such?"
I think your work in this particular situation will be a pioneering effort. You get to break new ground! Good luck.
Re: masking out with tricky lighting by moldyboot on Jul 3, 2007 at 4:23:32 pm
i'll give this a try, levels may be easier to work with then curves...
when you apply the levels effect, you should see a histogram... it is a graphical representation of the pixel information of the current frame. information on the left end of the graph is the amount of 'shadow' or dark detail, the right end is the 'highlight' detail and the center is the 'midtone' detail.
you can grab the center (gray) marker (called the gamma) and slide it to effect the lightness or darkness of the image. if you wanted to clip out some of the highlight detail, you can pull the right most (white) marker to the left, if you wanted to clip some of the shadow detail, pull the left most (black) marker to the right.
for the most part (for what you're doing) you will want to play with clipping some of the shadow and highlight values, using the gamma for fine tuning. you may still need to use masks and such, but this technique should get you close, pretty quickly.... once you've done it a few times.
multiply (and other blending modes) may change the colors too... if your colors are getting too saturated, try adding another duplicate of teh original footage to the top and set the blending mode to color or hue...
