Linear, log RGB, log neg, and Cineon printing density:
What’s in your DPX file?

1-day workshop

A publication-quality flyer is available in Acrobat PDF format. It's intended for printing onto a US Letter sheet, in color. Print it and tack it up on your bulletin board; or, print it at 140% onto 11x17 paper and it's a poster!

Upcoming dates:

Sydney: Took place at fxphd/Future Reality/Deluxe, in Lane Cove, Sydney, Australia, Thu. Jan. 19, 2012.

(Recent dates, see below.)

Description

DI houses and VFX houses are faced with a proliferation of acquisition formats including log RGB (“quasilog,” such as FilmStream, Panalog, and S-log), log neg (Cineon Printing Density), and “Rec. 709” in various forms (HyperGamma, Cine Gamma etc.). In addition, DI houses and VFX houses are presented with many formats described by DITs as “linear” but for which an 18% grey card does not approximate a signal code of 18 on a scale of 0 to 100! Any of these formats can appear in DPX files, but such files rarely contain sufficient metadata to identify the colour encoding.

In this 1-day workshop, Charles Poynton will introduce the perceptual and mathematical properties of linear-light, power function, and logarithmic encodings. He will detail the parameters of these coding schemes:

• Power function (gamma) encoded BT.709, sRGB, CineGamma, “FILM REC,”, and HyperGamma, including discussion of KNEE and SLOPE controls;
• Log RGB (quasilog/pseudolog) encodings: FilmStream (log₆₀), ARRI log F, Panalog, Sony-log (S-log), REDLOG, and SI log₉₀;
• Log neg encodings: Cineon printing density (CPD/DPX), ARRI log C.

He will describe the trade-offs involved in choosing encodings suitable for digital cinema and HD projects; he’ll review the bit depth requirements for high quality digital imagery represented in various forms. He’ll detail the 1D and 3D LUTs by which encodings are converted. He’ll explain the origins of gamma values 1.0, 1.7, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, and 3, and explain where each is potentially appropriate at various stages of the DI pipeline.

Who Should Attend

The attendee should be very familiar with digital cinema acquisition, and should be quite comfortable with mathematics, including equations such as y = m x + b and T = 10^–bE ^–m. The workshop will be suitable for people in positions such as these:

• Visual effects supervisors, VFX/post-production/DI engineers
• CGI/VFX and digital cinema software developers
• Advanced-level Digital Imaging Technicians (DITs)
• Film scanner, film recorder, and colour grading system engineers

Registration: circa USD 450, including refreshments. Lunch will be provided; you will have a chance to socialize with your colleagues. Detailed handout notes – some of which form portions of Mr. Poynton’s forthcoming book – will be provided. To enroll, e-mail charles@poynton.com.

Previously presented:

Toronto: Thursday, Nov. 26, 2009, 9:00 am - 5:30 pm
Technicolor Creative Services, DI Suite, 49 Ontario St., Toronto

Vancouver: Thursday, Dec. 3, 2009, 9:00 am - 5:30 pm
Deluxe/CIS Vancouver, 50 West Second St., Vancouver

Toronto: Monday, Dec. 21, 2009, 9:00 am - 5:30 pm
Technicolor Creative Services, DI Suite, 49 Ontario St., Toronto

Burbank: Monday, Feb. 22, 2010, 9:00 am - 5:30 pm
Dolby Laboratories, 3601 West Alameda Avenue, Burbank, Calif., organized by VTP.

Charles Poynton specializes in the physics, mathematics, and engineering of digital colour imaging systems, including digital HDTV and digital cinema (D-cinema). He is the author of Digital Video and HDTV Algorithms and Interfaces, and a Fellow of both the Society of Motion Picture and Television Engineers (SMPTE) and the BKSTS. He was the founding chairman of the SMPTE committee that developed the DPX standard.

Charles Poynton - Courses & seminars
www.poynton.com/notes/events/
2012-01-11