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-   -   Slow/mo and b/w (https://www.dvinfo.net/forum/techniques-independent-production/12186-slow-mo-b-w.html)

Neil Kissoon July 18th, 2003 12:23 PM

Slow/mo and b/w
Hello everybody. I have a couple question to ask. I pretty new to this site, but so far I have found everybody to be a tremendous help and great resource to us all. I have two quick questions regarding slo-mo(slowing or speeding up the frame rate) and black/white. Can this be done on the camera(canon xl1s) or does it have to be done in post. I am too traying to produce a film look, a film noir look to be exact. ANy feedback, comments or sugeestions/critiscims I will gladly welcome

Alex Knappenberger July 18th, 2003 12:33 PM

You can't do slow motion in camera, so you have to do it in post. With 30FPS video, you can slow it down in post to 33% (which is very slow), smoothly (atleast with Vegas 4) with good results. When you do slow it down in post though, remember to use 33% and 66% slow motion, since them numbers work the best in NTSC video.

Charles King July 18th, 2003 01:25 PM

"When you do slow it down in post though, remember to use 33% and 66% slow motion, since them numbers work the best in NTSC video."

Alex, then what about PAL?

Curtis T. Stoeber July 18th, 2003 01:53 PM

With these 66% and 33% numbers, is that for interlaced video? With my XL1 I usually slow it down to 50% and it is silky smooth if I shot it interlaced (vs Frame Mode). Each field gets 1/30th of a second and it looks good.

Neil Kissoon July 21st, 2003 06:54 AM

slow mo b/w
First I want to say thanks for the enormous feedback. Secondly, I'm shooting in frame movie mode. But Curtis has a good point, does it matter what mode?

Curtis T. Stoeber July 21st, 2003 07:05 AM

If you shoot the footage in Frame mode, it'll appear a bit choppier when you slow it down vs interlaced. I'd shoot everything in Frame mode, but then shoot the sequence to be slowed down as interlaced. What you might want to do is grab your XL1 and shoot a quick random shot in frame mode AND interlaced of the camera panning, someone walking, etc. Maybe 10 to 20 seconds worth of footage. Slow them both down and see which you like best.

Neil Kissoon July 21st, 2003 07:20 AM

When shooting interlacd vs. frame mode when it come time if I want to 16:9 (Electronic Anamorphic) it or if I want to blow it up/transfer it to 35 mm film. Thanks Curtis...

Casey Visco July 21st, 2003 09:15 AM

If you plan on shooting for a blow up to 35...you'll probably want to keep everything interlaced...most transfer facilities will want it this way.

Neil Kissoon July 21st, 2003 09:37 AM

slow mo - pal
Now here's another diliemna(I hope I spelt that right) I was reading Pal is the way to go to a 35 mm blow-up. How does that effect my slow-mo. Is it the same numbers? Pal is 24 fps. Thanks

Casey Visco July 21st, 2003 10:48 AM

PAL is 25fps interlaced, typically you can get away with not converting this to 24 for the blow up, it is barely perceptible.

Rob Lohman July 25th, 2003 05:12 AM

To answer your question of B/W. You can do that in camera on
the XL1s by dialling down the color gain under cstm preset
(you have 3 custom presets to choose from).

But I prefer to do it post so I can vary the levels of how B&W
I want it to be. If I don't like what I see I can always leave in
more color or don't make it B&W at all. That isn't possible, ofcourse,
if you record it B&W in the first place.

Scott Anderson July 28th, 2003 10:43 PM

And, don't forget, Rob, that if you shoot in color, you have the ability to have much more control in the post-processing, even if you choose to stay in black and white.

What I mean by this is that most programs will process footage in Red Green and Blue (RGB) color space. There is vastly different information contained in those three color channels. Just doing a simple desaturation to that image will wind up with a really flat look. You've seen it a million times, and said to yourself "oh, somebody applied the B&W filter. To get a truly stunning image (film noir-ish), you have to get creative with how you go from color to B&W.

I'll try to illustrate this with a short exercise in Photoshop. Seeing this in AfterEffects is easier because you can just click on the RGB channels, but more people probably have access to PS.

Take a picture, any color picture with red-ish, green-ish and blue-ish pixels, and open it up in Photoshop. Open it up 3 times, or copy & paste so you have 3 versions or the same picture. Now apply "Image, Adjust, Channel Mixer". Select either "Red Green or Blue" from the dropdown box and click "Monochrome". You're now seeing a B&W image produced only from the R,G or B pixels.

Notice how the contrast and relationships between colors changes dramatically depending on which channel you choose. You start to see how you can control your image much more by mixing those 3 channels BEFORE desaturating.

Rarely is a really cool B&W image going to happen unless you play aroung with the channels in post.

Neil Kissoon July 29th, 2003 06:34 AM

Thanks guys. Scott what d o you think about using a red/orange or yellow filter to enhance the contrast, or just leave it until post.

Scott Anderson July 29th, 2003 08:37 AM

As for using color filters on set to enhance contrast, it's certainly valid if you are certain to post-process to B&W.

When using B&W film, it was common to use a red filter, for instance, to darken daytime skies. The trick, of course, is to be certain that you're not affecting other colors that you want to keep in the shot (or keep those colors in the RG&B channels to use in post processing). Once you've used heavy filtration, there's no going back.

I would think that shooting as close as possible to your intended final look in full color is most advisable. Maybe you could even keep a monitor on set with the color turned off. This would at least let you look at the image in terms of pure contrast. Then it will be a matter of exerting very fine control over the image in post, rather than bluntly trying to force your image into shape.

That being said, by mixing the channels in post, you really will find a lot of flexibility in altering the B&W image. That's no excuse, however, from shooting the best possible-looking image in the first place.

Neil Kissoon July 29th, 2003 10:48 AM

Thanks so much Scott, I have a old monitor kicking around I'll probably use.

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