Question on "Saturation"

[Rob Simon]

I am usually reluctant to use filters other than ND, only because:
a) I'm too cheap to buy filters with names like super duper pro gold mist 1/8 (only to find out I should have bought the super duper pro gold mist 1/4)
b) I'm inexperienced with filters and may not like the result
and
3) It is not reversible, unlike adjustments in post.

I don't want to soften my images, so I think I have to stick with adjusting in post when it is necessary and just deal with the rendering time.

[Wayne Orr]

Sorry guys, but there is a lot of bogus information in this thread. Let me suggest that if you are serious about color correction, you look up Michael Kieran and "color correction." He has a couple of great books on working in Photoshop that will really get you on the right track. And better yet, if you are fortunate enough to be in a city where he is giving one of his all day seminars, I urge you to sign up and attend. They usually are sold out, so don't delay.

See if this link works http://tinyurl.com/6ex24

Wayne Orr, SOC

[Rob Simon]

Wayne,
Thanks for the link to the book. It does seem to be packed with info on the subject.

Do you believe understanding the concepts put forth with regard specifically to Photoshop would be helpful as I try to color correct my video using Final Cut Express?

I actually don't have/use Photoshop.

Thanks.

[Wayne Orr]

Yipes, Rob. You don't have Photoshop? Most people working in digital video find PS to be an absolute "gotta have it" in their bag of tricks.

That said, if you want to avoid PS, then you might try "Color Correction for Digital Video." Like most books with "digital video" in the title, it is trying to cash in on the dv craze, but there are some good tips and info to be found.

But if you really want to understand the concepts of color correction, you need something like one of Keiran's books, and Photoshop. I think some of the serious still shooters here will back me up on this.

BTW, Keiran had an older book that had a videotape that went with it. Don't know if there is one for the new book, but you might try contacting his site and find out. Very valuable asset.

Be advised: color correction is a very deep subject.

Wayne

[A. J. deLange]

There are various ways to represent color each of which requires 3 numbers for each pixel. In video one of the numbers represents how light or dark the pixel is. This is called luminance. If luminance information only is displayed one has a perfectly adequate black and white picture. The other two numbers represent the color (chrominance) of the pixel. If these two numbers are plotted on a two dimensional graph the point corresponding to 0 value for both numbers represents a point with no color i.e. a white, black or shade of grey. This point has 0 saturation - no color. As you move away from this "white point" a pixel begins to take on color with the amount being proportional to the distance from (0,0). Close to the white point the colors are subtle pastels. Farther away from it the colors become richer. Eventually one reaches the limit values of which the system is capable. The locus of points at the limit values represents the boundaries of the color gamut of the particular system. Such colors are fully saturated within that system though other still more saturated colors may be possible in other systems. In video systems the saturation (distance from (0,0)) is coded by the amplitude of the color subcarrier (and which color it is, red, yellow etc. is coded by the color subcarrier phase relative to the burst).

The ultimate saturation limit is light of a single spectral wavelength. The colors represented by such lights are the purest colors possible and are at the maximum saturation possible. Spectrally pure colors are well outside the gamuts of color films and video systems.

A video camera manufacturer selects a CCD block with capability of color measurement within a certain gamut (colors outside this gamut e.g. more saturated colors get squeezed into the range which the sensor is capable of handling and are thus represented as being less saturated than they actually are). He then has to choose how to code the colors the sensor measures and what he decides to do with saturation is one of his concerns. The manufacturers of film as well as cameras (still and video) have learned that consumers want vivid color and so have chosen to boost saturation in their products. One must buy special films if he wants true color reproduction and in many digital still and video cameras one must reduce saturation somewhat if true color reproduction is the goal. It is not a goal many strive to achieve and one can find endless discussions on the still camera boards about how this piece of raw file processing software give a much more pleasing result (often compared to a high saturation film like Velvia) than that piece which actually gives a truer rendition.

With programs like Photoshop or the NLE's it is possible to manipulate saturation to one's heart's content even varying the saturation in differnet parts of the tonal range separately. How one chooses to do this is, generally, a matter of taste with the usual choice being a saturation boost for more "vibrant" color. There are cases in commercial work where the client wants, for example, the image of his product's lable to represent the actual color of the product's label as closely as possible. In these cases saturation would be adjusted for truest color reproduction. In other cases, as in the one which kicked off this thread, the desire is to match the characteristics of one source to another or to match different sources. In these cases the sensors (film, or CCD) are "profiled" and the images converted into a "working color space" using this profile. This image represents the true colors of the imaged object (with repect to a particular illuminant). Similarly the output devices and print media (film, paper, CRTs) are profiled. By manipulation of the working space image with respect to the available output device (and any system it is desired to emulate) one can usually achieve the desired, or at least an acceptable result. An example of this latter would be the transfer function distortions done by modern prosumer cameras in an attempt to attain a "filmic" look. As another poster suggested, this subject gets pretty deep pretty quickly.

[Jose di Cani]

2 things that make movie interesting:

- use of shadows (blacks) and light (white); in normal hobby movies you see there is less action in the blacks. Try to blacken the shadows>>> gradient layers, hue layers, black diffusion layers (adobe after effects has some standard good ones)
- colours; in vhs movies the colours are dull. YOu want the mickey mouse disney kind of colours. Britht, warm and deep. >>> Hue/gamma filters


key is experimentation! Just try and see it for youself.

[Matthew Cherry]

I have Final Cut Pro HD and Photoshop CS. I have a lot of experience with photoshop but I'm not sure how I would integrate it into my FCP workflow, other than to export a frame at a time as a single image from FCP, modify it in PS and then somehow, reinsert it into FCP. I may be doing this in the future for some additional work on my short, but at 24fps this seems like a duanting task - but worth the result I think

Is there another way that folks are using PS with an NLE? Or I guess the better question is, how/why do you use PS when working with video?

Thanks,

Matt

[Rob Simon]

Matt,
Thanks for asking the question I've been hoping someone would answer without me having to ask. It is apparently obvious to everyone else!

[Stephen Schleicher]

I don't have FCP sitting in front of me, so I can't confirm you can do this, but many NLEs will let you export a filmstrip that can then be opened in PS. From there you could write a quick action to apply to all of the frames, save and reimport into your NLE

Cheers

[Wayne Orr]

Matthew, if your question is regarding using curves in PS for color correction, this is how it used to work in After Effects. You could export a frame to PS, open it, work on it till you were happy with the results, and then save the curves settings.

Open AE, select the clip you wanted to work on, open effects>color correction>curves, and in curves you would find the settings you saved in PS. Pretty slick. But I am not at all sure this would work with FCP.

Anyone know?

Wayne

[A. J. deLange]

I know either BTV or FCP or both will throw out a sequence of JPEGS but I can't remember exactly which and don't have either of them in front of me at the moment. But I do remember that FCP has color correction filters available because I use them all the time. The 3-way filter allows matching of color between cuts, adjustment of hue and saturation in each of three tonal ranges (shadows, mids and highlights) and there is an overall saturation slider as well. These controls can be used with key frames to allow gradual automated change (i.e. you don't have to do each frame individually). This has got to be easier than doing the conversion to and from PS even using batch processing in that program. What I don't find in FCP is curves control - the most powerful tool (IMO) for such operations. If it's there and someone can tell me where, please do!

[Wayne Orr]

OK, A.J., here you go. I downloaded "Color Finesse" demo from the www.synthetic-ap.com website and loaded into my Mac with FCP. I am still learning, but to do a correction with the software, you select the frame to work on and apply "Color Finesse" as a "filter" from FCP. This opens up the Color Finesse app with the frame, along with a myriad of controls and scopes, including very nice curves controls. This is a very sophisticated color correction app that gives better control than FCP's color correction.

And get this. If you make a curves correction to a frame in PhotoShop, you can save the setting, and open that setting in Color Finesse, which will apply it to your FCP project.

I have a lot to learn with Color Finesse, but I believe I will be making it part of my arsenal. Check out some of the demo footage at Synthetic-Aperture's site. Pretty amazing. And don't miss the free download of "Test Pattern Maker."

Wayne Orr, SOC

[Glenn Chan]

Curves in Final Cut:
see http://www.digitalzoo.com.au/lunchti...ee.htm#50point
Excellent website with links to which filters are free. Stib's generators I believe includes a curves plug-in.

2- Final Cut can export an image sequence for processing in Photoshop. Go to quicktime export and export an image sequences. Photoshop can use actions to batch process the image sequence.

[Glenn Chan]

I generally like the colors from my TRV950 (trees, grass look nice to me) but when I shoot, for instance, my son's team with orange jerseys in full sun, it looks like obnoxious video orange. Ideally, I'd like to tone down the orange but leave everything else alone, but don't think I can do that with the tools I have.

If you have Final Cut, use the 3-way CC.
http://www.kenstone.net/fcp_homepage...ille_look.html

The following article goes over all the button pushing you have to do. Instead of the pleasantville look however you might just want to tone down saturation on the orange jersey and perhaps shift it's hue slightly (use the three wheels on top... start with the middle one, which controls midtones).

2- Applying the 4:1:1 color smoother in FCP4 might help slightly with edges. If you look at the link above, notice in the very bottom picture that the left edge of the balloon is green from the greenscreen.

[Glenn Chan]

Can someone explain what "saturation" is, and how it differs from film to video?

I believe John Jackman hit it on the head:
The film gamma curve also tends to make darker colors more saturated and lighter colors more pastel.

From what I've read, underexposing film half a stop will lead to more saturated colors. Still photographers do this all the time. I believe some (moving) film DOPs do this too.

I personally don't find boosting saturation in dark areas to look that much better than boosting saturation evenly.

2- If Final Cut with the 3-way CC, you could use the limiting controls so that the luminance limiter/qualifier looks like a ramp. This would allow you to boost saturation more in the dark areas than bright ones.

3- An alternative approach to boosting saturation: Boost saturation evenly except for flesh tones. I like to leave flesh tones alone since overly saturated flesh tones look wrong and candy-ish.

In any program with secondary color correction (i.e. FCP's 3-way CC, Vegas 5+) just limit the effect to flesh tones and hit the invert button.

4- I generally find that boosting contrast (via curves) and saturation always makes a picture look more aesthetically pleasing. There comes a limit when everything looks candy-ish or there are artifacts since the coloring is so extreme.

5- I find the applying certain blurs reduces artifacting. Chroma blur (i.e. Vegas; FCP4 and free ones for FCP3) help reduce artifacts from boosting saturation.

Also, the "sex effect" will also hide artifacts (do a search for the sex effect). A variation on the sex effect is to super-impose the video onto itself, apply blur on the top layer and set the composite mode to multiply. Drop opacity on the top layer.

In Final Cut, use nesting to do this.

*Sorry for the final cut bias, everyone seems to be talking about it here. I prefer Vegas more and haven't touched a Mac for a few months.