chroma shooting tips!!!

[adolff]

hi all
i am writing u whatever i am aware of chroma ( green / blue / black ) shoot !
please fel free to correct me !
1) for dv shoot on green screen as the video signal is compressed and some color information is lost !
2) if its uncompressed highend format then use blue screen ! for compressed use green !
3)avoid clothing matching the color of chroma screen !
4) light screen from front
5) there should be no shadows on screen
6)use gels to neutralize the color spill on foreground objects backlight
7)keep at least 12 feet distance between fg ( foreground ) and screen
8) use no special filters while shoting
9)check the uniformity of lighting with a spot meter
10)avoid shiny objects with glossy surface or shiny surface
11)never use dimmers with lighting the screen as it lowers the color temperature, making the blue more orange
12)capture with better sampling ratios . 4:2;2.
13)check what stock the dop is shooting on
14)the dop should not use fog, difussion,superfrost or smoke when shooting chroma
15)light your screen for its hue and not just to make it bright
16) there should be no reflection of the screen on fg object or talent
17)shoot light colored objects with dark blue screen and adrk objects with green
18 ) use a flat lighting scheme as far as posible
can nebody help me shooting on black ?
thanks
please feel free to correct me !
adolf

[andy_dill]

That's a solid list, here's some notes from my own experience.

2) Even in uncompressed formats (film scans, Genesis footage) blue is the noisiest channel. I default to green across the board unless there's a reason to not use it.

some of those reasons are:
- have blond talent
- want an overall darker but still nicely exposed screen (green carries more luminance than blue)
- green spill is uglier and more noticeable

[spicyboyvipin]

n always try to shoot a clean background plate,it will help you in keying.
n shoot a picture of the lighting setup to project the same in 3d.

[paul_round]

"the dop should not use fog, difussion,superfrost or smoke when shooting chroma"
Try telling that to a DoP!

[rohit]

the colorist should not sharpen /denoise/deblur/use filters/or adjust the screen color....that part is more difficult to control than the DOP ! :)

[paul_round]

As Rohit says, absolutely no secondary grading whatsoever.

Paul

[7even]

Motion blur kills the best chroma screens. Using higher speeds on the cam often does a pretty good job.... but wants a "little" more light.

[rohit]

also..if shooting on good old film..avoid high speed film stocks [ thats another point to argue with the DOP ]

[rohit]

or simply adjust the shutter angle, but then u have to avoid panning movements

Motion blur kills the best chroma screens. Using higher speeds on the cam often does a pretty good job.... but wants a "little" more light.

[adolff]

please do take care of the tracking issues..
i realized that only lighting a perfect green blue screen doesnt help
u need to set the track points correctly
take correct measurements n get some survey info as well as camera data in order to save ur n ur teams life....
i hv edited the article in fxphd on set / tracking summary in short...
please do hv a look at it ..
:)

[rohit]

i prefer green trackers on green screen..just a slight diff in hue etc and its easy to track and easier to remove

[beast]

I would add:

-Use balls or circular tracking marks, not plus-shaped marks.

-Avoid the use of chroma screens in monitors or televisions when shooting them if the goal is a simple screen comp. Having the monitor/TV simply turned off offers the best result. If you have several objects/actors moving in front of the screen, only then should you consider a chroma screen.


Kevin McDonald
FLAME ARTIST
wheelmanfx.com