Tommy L

Quick question, does anyone know the ideal rgb values for both blue and green screen for background post-production seperation?
Many thanx
Tom.

Woody

Alright mate, you could find a pic of one on the internet and use the pipet tool in Photoshop to get the values.

JamesTaylor

i reckon the colours would be altered by what ever took the picture, may have been a traditional film camera which was then printed, maybe left for a period and discoloured before being scanned and then compressed to make a suitable file size for the web.

Also, the lighting conditions that were present when the original image was captured may alter the rgb value of the blue in an image.

akzit

Found this info on the web:

R: 0, G: 10, B: 145

Seems to look right on.

Attached Images

bluescreen.jpg (19.3 KB, 13 views)

__________________
"That you are here--that life exists, and identity;
That the powerful play goes on, and you will contribute a verse."
Walt Whitman

Christopher Nichols

It really all depends on how the scene we lit... It really does not matter as long as it is almost all green or almost all blue. Most people use green nowadays since you can key it better from Video. But color does not matter as much as lighting... that is the key (pun intended).

Can you tell us why you need to know? If you are trying to make your own green screen there is a lot you may need to know about....

__________________
Christopher P Nichols

Tommy L

I was seperating an RPC pass in Viz. The PRCs occasionally went behind elements on the scene so I applied a matte/shadow material to everything and made the background blue. This was so i could use the bluescreen setting in Premiere. I just wondered if there was an ideal blue that evryone uses. Turns out that it picked up the boundaries fine though.
Thanks for your help guys.

Chad Warner

Tommy-

Since you were successful in getting the RPC's to bluescreen correctly, can I ask you a couple questions?:

How did you deal with the "halo" that ends up being around the RPC from the transparency?

What about the shadows? This is where I don't know how to deal with the green screen or blue screen method....the shadows always pick up the color of the background.

Thanks,

Chad

wda

Color of a bluescreen/greenscreen.... consistancy (rendered unlit=no problems), another consideration is other similar colors in the scene (they may be masked to some degree), use purest primary color possible is best (other colors in the scene will not be that saturated and should be uneffected).

All compositing software that 'color keys' into an alpha mask works in a similar fashion, takes the 'color' value (rgb) and creates a greyscale based alpha mask from that value. So the greater the difference of value between the scene elements and the 'bluescreen', the highr quality mask.

WDA

__________________
From the calm seas.... Into the CG Fire...... Into the Heart of Texas