Glenn ChanREELSony Vegas Tutorials

Color Enhancement with Nattress Film Effects

Nattress Film Effects and other film look plug-ins are designed to emulate the look of 35mm film. However, why limit yourself? Why not try to make your video look better than film? This tutorial will look at how to use Nattress Film Effects to make the most of your footage. While this plug-in set won't magically make any footage like a Hollywood blockbuster, it does allow you to greatly change and improve the look of your footage.

BEFORE
Before
AFTER
After

Increasing Saturation

Increasing saturation can be used to breathe life into any image. To do this:

Add the "G Film Plus" filter to your clip. Scroll down to the Saturation controls. Shortcut: To quickly scroll down the interface, position the cursor in the left-hand column of the effects window and use the scroll wheel on your mouse to move up/down. Do not position the mouse cursor where the keyframes are, as this will set a keyframe instead of scrolling. Note that many Mac mice do not have a scroll wheel.

saturation interface

Enable the Saturation On setting.

Adjust the Saturation Amount slider.

The Also Desaturate? setting will lower the saturation of highly saturated colors, much like the knee feature on video cameras or an audio compressor. This setting will allow you to increase saturation further without creating overly saturated colors. I would suggest enabling this setting.

De-Saturation Amount controls the how much highly saturated colors are de-saturated. Settings outside the 0 and -1.00 range will produce abnormal results. The default setting of 0 and settings around -0.30 will work well in nearly all cases.

Increasing saturation generally makes images look better. I recommend that you always give saturation a little boost. How much to increase saturation by is a subjective decision. Subtler amounts will avoid overdoing the effect and causing the colors to look unnatural. If you would like to go for a look that stands out, then aim towards higher saturation. You can push saturation higher and higher until you find the effect overdone. Then back off from that point.

You may also wish to consider how your audience will see the image. Some television manufacturers intentionally increase the saturation in their displays. When your work is viewed on such displays, saturation will be increased twice. This can result in garish colors and unnatural looking flesh tones. To deal with this, I suggest that you keep the flesh tones close to normal saturation, while increasing the saturation of everything else. One method to do this is to use the 3-way Color Corrector and use the limit effect controls to lower saturation on only the flesh tones. Another method to adjust flesh tones independently will be outlined later on in this tutorial.

Gamma Curves

BEFORE
Before
AFTER
After a small change in saturation and contrast

Nattress Film Effects has several filters that generate various gamma curves. This tutorial will just look at G Gamma S-Gamma.

sgamma interface

The Gamma control affects overall brightness of an image. Gamma can be useful to affect overall brightness without pushing highlights or shadow into clipping. However, it does cause subtle shifts in hue and saturation. To avoid objectionable color shifts, only adjust gamma by small amounts (i.e. between 0.9 and 1.1).

S-Gamma Amount applies a s-shaped gamma curve that mimic film's gamma response. Its main effect is that it increases the contrast in an image. In doing so, it will compress shadow and highlight detail (without clipping). S-shaped gamma curves will also increase the saturation in the midtones and reduce saturation for highlights. This desaturation generally makes highlights look like specular reflections (i.e. light reflecting off a sweaty forehead). This usually will not look unnatural unless S-gamma Amount is very high.

You may find that S-gamma affects the overall brightness of an image. Use the gamma control to compensate for this.

Like saturation, how high to set S-Gamma Amount is a subjective decision.

Brightness (in this filter) adjusts white level / gain. By looking at the Waveform Monitor (under Video Scopes), you can adjust brightness until there are no values above 100. These illegal values will show up as red in the Waveform Monitor. You generally want to avoid values above 100 as they will likely be clipped, causing a loss in highlight detail.

As an alternative, you can use the Broadcast Safe filter (i.e. on the conservative preset) to take care of illegal values instead to using the brightness setting in S-Gamma. This alternative will take less time and result in slightly less highlight detail.

When setting levels manually via the brightness setting, watch out for the broadcast safe filter. The s-shaped gamma curve already compresses highlights. The broadcast safe filter will compress the highlights again. This can cause a slight loss in brightness and highlight detail. To avoid this, enter your own settings into Custom - Use Controls Below (select this from the drop-down menu in the Broadcast Safe interface).

Set Clamp Above, Max. Output, and Start (Threshold) to 100 to avoid compressing highlights. These settings will clip off any illegal luma values, acting as a safety net.

Do enable Saturation Limiting. When your digital video is converted to analog signals, it may result in illegal composite analog values (these illegal values may interfere with other signals). For DVD distribution, the maximum composite analog value allowed is around 130 IRE (~133.33 IRE if there is no 7.5IRE setup). For broadcast, the maximum composite analog value allowed varies from broadcaster to broadcaster. 110 IRE is generally a good conservative value, although go with the broadcaster's figures if they provide them to you.

Clamp Above: Clamp above and start (threshold) determine which range of values will be compressed to fit within the legal range. Clamp above sets the upper boundary of this range. You can usually leave this setting at 133.
Max. Output: Put the maximum composite IRE value here.
Start (Threshold): This setting and the one above determines how illegal values are compressed into the legal range, much like an audio limiter. The Start (Threshold) setting should usually be less than the two settings above.
Reduce Chroma/Luma: This setting is purely an aesthetic choice. To lower illegal composite values into legal range, Final Cut will lower a combination of the luma and chroma. Luma and chroma are approximations of luminance ("brightness") and saturation, respectively. You can tweak this setting if you do not like how the colors look after applying the broadcast safe filter.

Which approach you take is up to you. For the sake of efficiency, I would prefer not touching the brightness control in S Gamma. Instead, use the broadcast safe filter on one of its presets (not the custom controls).

Not using brightness
Before. Note that the wire in the upper right is less defined. Also note the highlights in the center and in the windows on the left.
setting levels manually
After setting levels manually via the brightness setting.


Correcting Flesh Tone Independently

You may find that increased contrast and saturation can cause flesh tone to look too unnatural. This effect can be magnified if the viewer's television increases saturation levels itself. One method to avoid this is to put flesh tone onto its own video track. Doing this will allow you to really push contrast and saturation while leaving the flesh tones relatively neutral.

First, duplicate a clip onto a higher video track. Hold down Option, and then click on the clip and drag it onto a higher video track. Before you release the mouse, hold down the Shift key/modifer. This will perform an overwrite edit insert of an insert edit.

Remove filters on this duplicate by right-clicking on the clip and selecting Remove Attributes. Check the box beside filters and click ok.

remove filters

Decrease the opacity on the clip to about 60% or so. One way to do this is to double-click the clip to load it into the Viewer. Click on the motion tab and enter 60 for opacity. Doing this will blend between the footage with and without corrections. This will actually result in a more normal-looking image than leaving opacity at 100%.

Add the Chroma Key filter. Select the eye dropper and click on flesh tone within the image. You can shift-click other areas of flesh tone to include those colors in the selection. Sometimes, you may need to adjust the matte created.

Chroma Key interface

In the hue controls (where the rainbow/colored gradient is), drag the handles on top outwards. You can drag the handles below to increase the smoothness in the chroma key, creating a smoother transition from what is in the matte and what isn't in the matte.

In the sat controls, you can drag the right-most handles far to the right..This will include highly saturated reds/oranges along with the flesh tone. This is beneficial to these example images to prevent the red shirt from becoming obnoxiously saturated.

De-select the box beside Luma. In situations like this, this setting is unnecessary.

Clicking on the key icon will toggle between the final result, a display of what the matte looks like, and the image without any effects. Using the matte display can be very helpful to see what you are isolating.

To make the transition between the two different corrections more seamless, smooth out the matte via the Softening and Edge Thin settings.

BEFORE
Before
AFTER
After coloring flesh tones seperately

Once you have a set of filters you like, you can save them into your Favorite Effects folder. Drag the filters from the Viewer into the appropriate bin in the Browser. To apply these filters to multiply clips, select a group of clips and drag the filters from the Browser onto the selection of clips.

Conclusion

Increasing contrast and saturation almost always makes footage stand out and look better. When compare stills side by side, the higher contrast and more saturated image will almost always stand out more. If working with video-originated footage, increasing contrast and saturation will provide a very good starting point in making your footage look better. However, this does not mean you should always increase saturation and contrast. For example, a high-contrast but de-saturated look (i.e. similar to bleach bypass) would be appropriate in creating a sombre mood. When coloring any work, do exercise some creative judgement. Nevertheless, for more mundane material (where no mood is required) you will likely want to make the image 'pop' by increasing contrast and saturation.

One last thing to consider is time spent correcting your material. Your projects may be limited by looming deadlines. If speed is your goal, then I suggest the following:

Of course, if you have more time then you can consider going into more detail (i.e. putting flesh tone on its own layer, using G Film to adjust saturation instead of the 3-way Color Corrector).

Happy coloring!



This site by Glenn Chan. Please email any comments or questions to glennchan /at/ gmail.com Eric Caton / Jemtec Boundary Noise Reduction reviews / comments versus Picturecode Noise Ninja, Imagenomic Noiseware, Topaz Denoise, Picture Cooler, Neat Image, etc.


My plugins:
Photoshop color correction
Photoshop noise reduction
Freeware

I wasn't satisfied with the tools in Adobe Photoshop so I made my own. Check them out!