5 replies to this topic

[Stephen Williams]

Hellow everyone!

Does anyone have experience on filming a Green Screen in Viper's Filmstream mode?
We're going to run some tests these days!
We think that we might get in trouble when pulling a matte, because the Filmstream mode produces an overall green image.
So our keying software (Quantel eQ) may think our foreground actors are too green also and include them in the matte.

Would it be a good solution to film with a megenta filter in front of the lens, to correct for the green in the image. (Maybe also affecting the backgroud green a little...?) Any other suggestions are very welcome!

Gretings,

Dennis Verheijen
Pentamagik
The Netherlands

<{POST_SNAPBACK}>

Hi,

To get the best out of Filmstream you should oplically filter the image using a MFX Digital designed filter, for your white balance.

For more information www.digitalpraxis.net


Stephen

[Rob van Gelder]

Dennis, are you keying the unprocessed Filmstream data?
I thought, that after you have adjusted the image for the right look, color balance, detail, etc, THEN you apply the key?


or is it for live-keying?

[Gavin Greenwalt]

Yes, we will be keying the unprocesseds Filmstream data.
Since our green screen hasn't been finished yet, we don't have any material for testing yet. But I would think that color correcting the image with green screen would also affect the color of the screen. So keying could be looking less good?
But now you mention it, it is worth trying.
As we'll do some testing I drop my experiences in here!

Feel free to add any advices!

Dennis Verheijen.

If you were shooting in 8 bit linear that would be a problem. The great thing about shooting log or half float is that there is more data there than "meets the eye" on a reference monitor. Even if you reduced the green cast by 50% you still aren't going to get color artifacts because of the color precision. Think of the color of your green screen with the Filmstream green cast as "super green", yes it will get less green, but only to normal acceptable levels. If this wasn't the case all viper films would be completely lacking in rich greens, which would be unacceptable.

- Gavin