## CALIBRATION PROCEDURE - Rec.709 Gamma 2.4 ### PREPARATION %% WaSAB (Warm-Up, Shield, Adjust Ambience, Bars display) %% - [ ] Activate Colour Reference Display, and allow to warm up (15-30-mins) - [ ] Shield Display from extraneous light and glare - [ ] Adjust ambient lighting to your expected viewing conditions - [[Rec.709 Gamma 2.4\|Rec.709 Gamma 2.4]] recommends a dimly-lit ambient environment; Not completely dark, nor full daylight (Think an evening living room at prime-time). - [ ] Configure Display Colour Profile / Preset (If req'd) %% - [ ] SAMSUNG Q7F - Color Profile - √ Rec.709 Gamma 2.4 - [ ] /Library/Application Support/Adobe/Color/Profiles/VideoHD.icc - [ ] /Library/Application Support/Adobe/Color/Profiles/HD_Display.icc - [ ] BMDResolve Preferences... > System > General > 🚫 Use Mac display color profiles for viewers - DISABLE - Prevents PLUGE Bars from crushing to solid black, and assists with achieving target Gamma of 2.4 %% - [ ] Reset Display as req'd - [ ] Configure Display Colour Temperature - √ D65 - [ ] Configure Display Gamma - √ 2.4 - [ ] Output Colour Bars ([[SMPTE RP 219-x - Colour Bar Test Patterns\|SMPTE RP 219-x]]) to the Display, generated by source equipment or software - [ ] **CONTRAST (Picture)** - √ Midpoint (50/100) - [ ] **CHROMA / COLOUR / SATURATION** - √ Zero (Monochrome) ### WHITE LEVELS - Reference White - [ ] **BACKLIGHT (Luminance)** - Adjust while measuring Peak White (100 IRE) with a [[Colorimeter\|Colorimeter]], Probe, or [Digital Spot Meter]()... - [ ] Peak White ≈ 100 cd/m² ([[nits\|nits]]) luminance - 100 nits is the commonly used reference luminance for [[SDR - Standard Dynamic Range\|SDR]] mastering displays - ⚠️ Actual targets may vary slightly with viewing conditions and ambient lighting %% BACKLIGHT - [ ] BT-4LH310 = 150 %% ### BLACK LEVELS - The [[PLUGE - Picture Line Up Generation Equipment\|PLUGE]] %% CONTRAST-MIDPOINT CHROMA-DESATURATED - CoMChD %% - [ ] **BRIGHTNESS** - Adjust while referencing... - [ ] **Middle PLUGE Bar (+2 IRE)** = Barely Visible - [ ] **Right PLUGE Bar (+4 IRE)** = Visible - ⚠️ If Middle or Right PLUGE Bars are *not* visible, increase brightness until they become visible. - [ ] **Left PLUGE Bar (-2 IRE)** = Not visible - Should merge with surrounding black regions (0 IRE) - ⚠️ If Left PLUGE Bar (-2 IRE) is visible and distinct from surrounding black regions (0 IRE), check Brightness, Contrast, Gamma, or Source Equipment and Software. - 'Scaled' Video Levels, or Gamma mismatches are a common cause of 'lifted' Black Levels. %% BRIGHTNESS - [ ] BT-4LH310 = 50 - [ ] iMac Pro = 3 - [ ] MacBook Pro 2019 = 11+1/4 %% ### CONTRAST - Signal Gain - [ ] **CONTRAST** - Adjust while referencing... - [ ] **RAMPS** - Luma (Y') and RGB @ Legal [[Video Levels\|Video Levels]] - [ ] Increase Contrast until brightest range begins to merge or stops getting brighter - [ ] Carefully reduce Contrast until brightest range is fully detailed - [ ] All three RGB channels should track smoothly up to reference white (100 IRE) without clipping. - RGB Ramps are available at 09:59:54:00 of the [[SMPTE RP 219-2a-2026 FMTV - UHD Colour Bars and Head Leader]] - [ ] ⚠️ Beware Excessive Contrast... - Highlight and / or Shadow detail will 'clip out' - On a CRT screen, the 100% White Bar (100 IRE) may also 'bloom and flare' - [ ] Allow the Display’s native behaviour for Super-white levels (101–109 IRE) - Slight extension or soft knee is fine. Avoid clipping so early that it distorts the upper range or shifts chroma. Super-white detail in the 'Peak' bar may remain, depending on system configuration. - [ ] **FINE-TUNE** - Iterate 1-2x as req'd... - [ ] [[#WHITE LEVELS - Reference White\|WHITE LEVELS]] - [ ] [[#BLACK LEVELS - The PLUGE - Picture Line Up Generation Equipment PLUGE\|BLACK LEVELS]] - [ ] [[#CONTRAST - Signal Gain\|CONTRAST]] %% CONTRAST - [ ] BT-4LH310 = 50-53 %% ### CHROMA-PHASE - Blue-Only Adjustment 🟦 %% - ==[[12.15 Blue-only colour bars]] shown in black-and-white for clarity.== - ==Notice that the bands are of equal intensity and in the uppor portion, the large and small bars are equally gray or black.== Most professional monitors have a blue-only switch (Fig. 12.15). - This turns off the red and green guns / channels, leaving only the blue. - If your monitor does not have a blue-only switch, you can use a piece of blue gel (full CTB) or a Kodak Wratten #47 — the purest blue in the wratten series. - [ ] View the monitor through the gel. - [ ] If you see any of the red, green or yellow colours, double the blue gel over to increase the blue effect. By using the blue-only switch or a piece of blue gel, you have removed the red and green elements of the picture. Only the blue remains. - If the HUE setting is correct, you should see alternating bars of equal intensity. %% - [ ] **BLUE ONLY** - √ ENABLE - [ ] View the test pattern... - [ ] While displaying only the blue channel, or... - [ ] Through a CTB / Kodak Wratten #47 blue gel in front of your eye (doubled if req'd) - [ ] **CHROMA / COLOUR / SATURATION** - Adjust while referencing... - [ ] **BLUE = 75% GRAY Bars** - √ Match - [ ] You can also match either the GRAY or BLUE bars with their sub-bars, when using a split-field, castellated colour bar test pattern. - [ ] **PHASE / TINT / HUE** - Adjust while referencing... - [ ] **CYAN & MAGENTA Bars = 75% GRAY BAR** - √ Match - You can also match either of them with their sub-bars, when referencing a castellated colour bar test pattern. - [ ] All Four Blue-Only Bars - 75% GRAY, BLUE, CYAN and MAGENTA should now be of equal intensity - The YELLOW, GREEN and RED bars should appear completely black ### 'BALL-PARKING' COLOUR - ⚠️ Not recommended. Professional calibration technique is far more accurate for reference environments. - [ ] Yellow (YL) should appear 'lemon' yellow, not orange or green. - [ ] Magenta (MG) should not appear red or purple. ### WHITE BALANCE - 2 POINT - [ ] **GAIN & BIAS** - Adjust R and B to match G, while measuring GRAY with a [[Colorimeter\|Colorimeter]]... - [ ] **≤75% GRAY** = GAIN - [ ] **≥20% GRAY** = BIAS / OFFSET - [ ] Iterate 1-2x ## ALSO - [[SMPTE RP 219-x - Colour Bar Test Patterns]] - [[APP, iOS - Carolina RGB Colorimeter]] %% # SMPTE RP 219-x Colour Bars - Rec.709 Gamma 2.4 %% %% ~~[[12.12 Diagram of blue-only signal.]]~~ ~~12.13 Correct monitor setup, shown here in black-and-white~~ ~~12.14 Incorrect luminance or Y gamma; notice how all three of the PLUGE bars in the lower right are visible.~~ %% %% # [[240110Wed]] # SMPTE COLOUR BARS ![[CALIBRATION - Colour Reference Monitor - Figures - SMPTE Split Field Colour Bars - Legend.pdf]] ^[Extracted from [[231222Fri]] on 240110Wed @ 18:01] %% %% The mathematical representation of colour and the human perception of it do not correlate exactly. Color Bars are an artificial electronic pattern produced by a signal generator, either hardware or software based, in-camera, on-set, or in a Post-Production facility, be it in telecine, editing, or duplication. Colour Bars are encoded at the head of every video deliverable to provide a consistent reference signal in Post Production. Colour Bars are used for matching the output of multiple cameras in a multi-camera shoot and to calibrate up a reference video monitor. %% %%