Color - Film/DLP Projection

[Keegan O'Brien]

I realized a contradiction between two, both of which knowledgeable and trustworthy, sources in terms of color between film and digital projection. The first source is David Keighley (Head of IMAX DMR), who in a late 2010 interview said that current digital IMAX projectors are capable of nearly 1,000 shades of color, whereas 15/65mm film is capable of producing 4,000 shades colors. The second source is the common advertisement from nearly all 3-chip DLP projection companies, that their projectors are capable of producing 35 trillion shades of color. Obviously there's a huge misconception somewhere... so I was curious as to the truth of the matter, considering that IMAX's digital projectors are 3-chip DLP systems.

Thanks.

 

[Chuck Z]

Let me try to explain what David was possibly thinking:

Digital IMAX projectors ~ 1000 gradations of color (2^10 = 1024); in a RGB color space that's 2^10 x 2^10 x 2^10 = 1.073 billion colors
IMAX film ~ 4000 gradations of color (2^12 = 4096); similarly you can do the math--2^12 x 2^12 x 2^12 = 68.7 billion colors
3-chip DLP projectors as marketed by Christie, et. al. ~ 35 trillion colors; working backwards that's (3.5x10^10)^(1/3) --> 32768 ~ 2^15

To be more specific, I believe David thinks Digital IMAX projectors are only capable of 10-bits per color component output, whereas IMAX film has the equivalent of 14-bits per color component when digitally scanned and ingested. All of the major DLP cinema projector vendors advertise their products of 15-bits per color component output. I think the DCI standard only calls for 12-bit XYZ at most, so some of the marketing specs is fluff.

Given that the Digital IMAX projectors are the very same as the ones from Barco, Christie, etc. those projectors can at least do 12-bits per color component.

 

[Keegan O'Brien]

Let me try to explain what David was possibly thinking:

Digital IMAX projectors ~ 1000 gradations of color (2^10 = 1024); in a RGB color space that's 2^10 x 2^10 x 2^10 = 1.073 billion colors
IMAX film ~ 4000 gradations of color (2^12 = 4096); similarly you can do the math--2^12 x 2^12 x 2^12 = 68.7 billion colors
3-chip DLP projectors as marketed by Christie, et. al. ~ 35 trillion colors; working backwards that's (3.5x10^10)^(1/3) --> 32768 ~ 2^15

To be more specific, I believe David thinks Digital IMAX projectors are only capable of 10-bits per color component output, whereas IMAX film has the equivalent of 14-bits per color component when digitally scanned and ingested. All of the major DLP cinema projector vendors advertise their products of 15-bits per color component output. I think the DCI standard only calls for 12-bit XYZ at most, so some of the marketing specs is fluff.

Given that the Digital IMAX projectors are the very same as the ones from Barco, Christie, etc. those projectors can at least do 12-bits per color component.

Well, Math has always been my sore subject, but I'll trust you on this. Thanks for the information.