color correction question

[Philippe Gosselin]

Hi all ,

Well I've reached another step in using Vegas now : color corretion.

I found a very good tutorial online that demystified it a LOT !!!

http://www.wideopenwest.com/~wvg/tutorial-menu.htm

The big question that keeps hanging above my head is this one :

Which type of color correction would I use for a specific situation/task.

There are so many , color curves , color correction and secondary color correction , HSL , channel blend seems to let one change colors as well.


So for example , I am now working on a project shot in a nightclub (not the same one posted earlier) , in this case which one would be the most appropriate to use

thanks

Phil

[Gary Kleiner]

> I am now working on a project shot in a nightclub<

The filters aren't organized by where the footage was shot, so you'll have to be for specific on what problem you are trying to solve, or at least post an image.

Gary

[Philippe Gosselin]

Hi Gary,


Well I am not actually seeking information on a particular case , using my current project was just an example.

Basically all I'd like to know is in which specific situation would a certain type of color correction tool more appropriate than another.

The example of the nightclub gives one particular situation in which it is pretty dark and accentuating the colors would add a nice touch.

Hope things are clearer.

Thanks

Phil

[Gary Kleiner]

Your question is not answerable, but:

Accentuating colors would be part of Color Corrector, or Color Balance, or Color Curves, or HSL adjust.

Accentuating a particular color would be Secondary Color Corrector or Color Curves...

Often, you just have to try a few different things and see what you like best.

Gary

[John Hudson]

Philippe

Can you provide a sample grab? Sometimes making an adjustment on the Saturation can help the colors pop. Give me a sample!

:)

[Glenn Chan]

Well first look at your goals. I will assume common problems/goals people face.

Too much noise/grain:
Use a noise reduction filter or technique of some sort. You can run footage through Virtualdub's filter for the best noise removal/hiding/masking.

Within Vegas, there are various options.

Satish's Photoshop plug-in plug-in + a PS noise removal tool like Noise Ninja.

The median filter. (SLOW SLOW SLOW SLOW)

Add diffusion:
Quick blur. Drag the slider to the right.
Magic Bullet Editor's / Black Diffusion.
"sex effect" duplicate video onto itself, add gaussian blur to top layer and set opacity to around halfway.
Same as above, except opacity at 100% and compositing mode to multiply. (This is an entirely different look, very contrasty.)

After that, you can use color curves to crush the blacks (where the noise resides).

Adding a wash/tone to your image:
Use the color corrector, and drag the wheels to three different colors. I suggest slightly different colors, as this gives more depth than just doing one color.

If you want more advanced control go use the curves filter. The color corrector is much faster to setup and 3 different tones is fairly good.

Just make the image look nicer:
The #1 thing you can do is to add the curves filter and make it look like a s (just mildly). This increases contrast and makes your video look sweet (most of the time).

Next step is raising saturation...
You can use the curves filter to boost saturation, but not in an even way. Boost the low saturation colors more so than the highs.

An alternate approach is to treat the saturation of skin tones differently than the rest of the image. Use the secondary color corrector to eyedropper an area of skin tone. Tweak the isolation until the mask looks nice. Inserting the Chroma Blur filter beforehand may help. In bad cases you can blur the mask: Duplicate video onto itself, secondary CC on top layer. Tweak the secondary CC for skin tones, and set the alpha to 0. Use the mask generator (set it to alpha). Set the compositing mode of the top layer to multiply. On the track below, set it as a child to the track above. Apply saturation adjustments to the bottom track.

Make sure your video is broadcast safe though... the two things above will create illegal colors.

Fixing exposure:
Bring up the vectorscopes, and check the settings are correct. Turn on the 7.5IRE setup box, and the studio RGB box (in most cases).

Set the vectorscope to the "histogram" setting/mode.

Apply the curves filter to a clip. There's many different approaches to this, but you want to move the curves around so that the image looks good.

Underexposure:
Add a point slightly down from the top. Drag it left until you see most of the histogram fill up (up to like 4/5ths of the way across). Smooth out the corner there (make it round, not pointy). This should raise the overall exposure level while compressing the few highlights in the scene.

The histogram will help you see how much of the available dynamic range you are using.

Once you've tweaked exposure to your taste, make sure your video is broadcast safe. The easiest way to do this is to dump the BS (broadcast safe) filter onto everything. In the video preview window, click on the FX chain there and add the BS filter.

Choose the conservative - 7.5IRE setup preset, and drag the smoothness sliders to the right.

You can get much better control with curves, but that takes too much explaining. (I'm lazy...!)

Tweaking a particular color:
Use the secondary color corrector (color corrector secondary).

[Josh Bass]

If anyone cares. . .

I think the easiest way to do the S-curve the color curves plugin is to create a point right in the middle of the diagonal line, and drag the point straight down (or is it up? I think it's down) til it looks good. I used to make three points, and I now see this is silly.


So, we DO want Studio RGB, and the 7.5 setup box checked?

[Philippe Gosselin]

Awesome guys ,

I got to get to work , i'll post a screenshot and comment on the wonderfull feedback later.

Thanks

[Glenn Chan]

So, we DO want Studio RGB, and the 7.5 setup box checked?

For North American NTSC DV, the answer is yes. Check both boxes on the video scopes.

For Japan NTSC, don't check the 7.5IRE box.

For PAL, don't check the 7.5IRE box.

For formats other than DV, read the manual(s).

[John Hudson]

Awesome responses guys!

[Rob Lohman]

The original link is a well known one among Vegas users, some
create tutorials there indeed. I've also added it to the sticky info
thread in this forum:

http://www.dvinfo.net/conf/showthrea...threadid=20830

[Philippe Gosselin]

Hi all,


Well this is some really nice info . Ok for those who wanted screenshot you can downlaod a small zip fille through this link:

http://s7.yousendit.com/d.aspx?id=1X...81QN9LWD6VLE9K

image 1 : you see that the image is too dark , colors don't appear

image 2: another dark image but that was before playing with color corretion

image 3 : after playing with filters

Let me know what you think

Rob : the only good link ( for color correction purposes)I found in the sticky thread leads to a page I actually visited before starting this thread but thanks for the reminder.

[John Hudson]

These grabs look as though they were shot trying to 'force' the exposure. Think trying to see in the dark with the camera and opening up the iris so much that feed back starts appearing. You should have exposed for the highlights.

Unfortunately, there is already alot of that in these so trying to bring the image out even further will result in even more feedback.

Attempting to bring out the color (saturating) will result in even more as there is not that much color to begin with (particulary the young lady that is in the red light; it already is a little hot) so that eliminates that option I think.

In short (too late). Next time try exposing for the highlights and don't attempt to 'see everything' inside the dark club; it wont happen.

I think to make these images better you have to reduce the grain (feedback, which is the video signal trying to latch on to something).

[Philippe Gosselin]

Hi John

Awesome feedback , thanks for your time.


I know I shot it too dark , i actually had bought a spotlight for my GL2 but dimmed it so much it was like I didn't had it at all :). I've learn my lesson for next time.


I did play with some color correction tools and adjust brightness and contrast , 1rst screenshot is without the effects and 2nd one is with the effects.

http://fapomatic.com/show.php?loc=7&f=image1_18.jpg

http://fapomatic.com/show.php?loc=7&f=image2_13.jpg


What do you think , looks like a white curtain has fallen over the image but it's still acceptable ....

What do you mean by "next time try exposing for the highlights"

Thanks

Phil

[Glenn Chan]

Philippe,
Try this:

Duplicate the video onto itself (in the track column, you can right click and duplicate track).

Top layer:
Set composite mode to overlay.
Add gaussian blur to the video. Something like 0.017 horizontal and vertical will work.
For this particular image, add the channel blend filter. Set it to blue or green.

Bottom layer:
Set the composite mode to child (in the left track column). This is so other tracks don't get messed up.

Add the unsharp mask filter... set it on something like the light or medium preset.


This hides the noise too ways:
1- The overlay mode increases contrast in the image (and affects saturation). It crushes the blacks/shadows (where the noise is) and crushes the highlights. Overall you get a high contrast image.
2- The diffusion effect from the gaussian blur also helps hide the noise.