Help with changing color of one part of the image

essami wrote on 4/30/2010, 12:39 PM

Hi!

I need to change the color of a hood of a car in one shot. The hood of the car is red and I need to change it into a blue/greyish colour. I got pleasing results by using secondary color corrector. Of course it changes the whole image and theres stuff on the frame that I dont want to change color, how would I apply a mask so that the color change I applied only effects the portion of the image that has the hood of the car and not the rest of the image? Cookie cutter?

Sami

Comments

xberk wrote on 4/30/2010, 1:46 PM

Probably a custom hand drawn mask is the way to do it but - ---
Can you post the shot of the car? .. Is it static or moving -- in other words does the mask keep changing (animating) ?

essami wrote on 4/30/2010, 2:20 PM

Yeah it keeps changing a little bit. Not a lot but it's not a static image, I could keyframe the changes by hand maybe. Unfortunately I cant post the footage before the release of the video.

Sami

xberk wrote on 4/30/2010, 3:27 PM

This is not the kind of thing I really do in Vegas but I think you'll need to use the Bezier mask in pan/crop to "cut-out" your car hood so as to change it's color. The means the mask has to change as the car hood image changes. This should be done frame by frame but you might be able to do a bit less --- you can keyframe the mask and Vegas will supply the postions "in-between" as the mask moves smoothly from one keyframe to the next on the timeline. This takes some learning to understand how to re-shape the mask at the different keyframe points as the image changes. IT can be done. The important thing here is that as things progress on the pan/crop timeline you are moving and reshaping the same mask. Do not create two masks. I think that's right.

The link below has a long discussion about bezier masks. The second post has a link to a nice SONY tutorial.

Bezier Masks in a nutshell

John_Cline wrote on 4/30/2010, 3:32 PM

If there is no other red in the frame, then the chroma keyer could be used to create the mask to change the color of the hood.

essami wrote on 4/30/2010, 5:02 PM

Hi,

Thanks, I think the bezier mask is doing the trick!

A simple question, after I make a path, how do I move an individual point to another spot? So simple but I just cant get it to happen! I have the "normal edit tool" selected but everytime I click on a point it manipulates the curving or moves the whole mask...

Sami

xberk wrote on 4/30/2010, 8:17 PM

Sami this is the blind leading the blind -- I don't really do much with masks ---

With the normal edit tool
If the path is showing the "points" -- right click and choose Deselect all or simply left click on any area away the mask path. Now no points are selected.
Left Click on the path near where you want to move a point.
The points will light up. You can now use the edit tool to drag a point and change the shape.

Read the Vegas help under "pan/crop" then "create bezier mask" - it's all there.
Paul

essami wrote on 5/1/2010, 3:46 AM

Hi Paul!

Thanks a lot! I tried reading the help section but all it says is when in "normal edit tool" Use that to select and edit control points and tangents. Click a point to select it, or drag to move the point.

But I think I figured it out as you say first you just click outside the mask and make sure no points are selected, then you can select individual points. With Alt pressed down and clicking it selectes all points so you can move the whole mask.

Its working and Im getting there :) Thanks so much for all your help!

Sami