Posted on June 25, 2018 By Eric Pfoutz
Acer VL7860 4K UHD Laser Projector Review – Calibration Settings: Calibration Presets Notes, Best Mode Calibration, Brightest Mode Calibration
The VL7860 has 10 modes (Bright, Standard, sRGB, Rec.709, Movie, Dark Cinema, Game, Sports, Silent & User. Plus 2 locked ISF modes that add CMS controls. I spent most of my time with Rec.709 and User. All of these modes have the same controls, what sets them apart is how these controls are preset. They all offer 3 color temperature options (CT1, CT2, & CT3) 2-point grayscale adjustments, gamma presets 1.8 – 2.4.
I used Rec.709 mode for my Best/Dark Room calibration. Brilliant Color is off by default and I left it off for my calibration. Sharpness was defaulted to 10, I reduced it to 4. Super Resolution, which is a global control was set to 2, I left it there. There is another enhancement section called AcuEngine which houses AcuColor & AcuMotion, both are off by default and I kept them off. Also note that AcuEngine is not accessible with 24p content.
Rec.709 mode out of the box definitely could use some improvement, measuring 4 to +12 DeltaE between 10 – 100 IRE. Remember we want to be below 3 and I always strive to hit 1 or less if the projector is capable. The average color temp was 8000K range, quite a bit cooler than our target of 6500K (D65). No matter where I set contrast the whites clipped at 232 just shy of our target of 235. I lowered contrast to 48 to help with grayscale tracking. After calibration, I was very pleased to hit 1 to 1 1/2 DeltaE across the entire grayscale (10 – 100 IRE).
My target gamma for my Best/Dark Room calibration was 2.4. Setting the projector to 2.4 gamma averaged pretty close at a 2.34. After calibration gamma tracking was actually a little worse at the 80-90 IRE. but the big improvement in white balance was well worth the tradeoff.
Overall there were no real surprises with my Best/Dark Room calibration. All of the controls work as there supposed to and yielded exceptional results with pleasing, natural colors and skin tones.
Note: The CMS controls are locked behind the 2 password protected ISF modes. Even though I knew our readers won’t be able to use my CMS settings I still wanted to evaluate how well they worked in improving the color accuracy of the VL7860. For those who want to see my pre & post color gamut charts along with my calibration data you can find them on our Advanced Calibration page.
Measurements taken at Mid Placement with Normal Lamp.
Average Gamma Pre-Calibration: 2.34
Average Gamma Post-Calibration: 2.41 @ 1341 Lumens
White Balance calibration settings for Night mode.
Delta E is a metric for understanding how the human eye perceives color difference. The term delta comes from mathematics, meaning change in a variable or function. The suffix E references the German word Empfindung, which broadly means sensation. Simply put, look at Delta E as a measure of grayscale/color accuracy. 3 and under is considered ‘Excellent’ and imperceptible by the human eye.
I used User mode for my Brightest mode calibration. By default, Brilliant Color is on and I left it on for my calibration. The only reason I leave it on is it increases the white level output which is what we are after for a bright room calibration. If you are looking for pure accuracy leave it off like I do for my Best/Dark Room calibration. The before calibration DeltaE was in the 4 to 9 range. Average color temp was 7200K, a bit closer to our D65 target than Rec.709 mode. This is because Brilliant color effects white balance. After calibration, I was able to get DeltaE down to 1 across the entire grayscale range except for 10 IRE which measured about a 4.
Like with my Best/Dark room calibration I reduced sharpness from 10 to 2 and turned off AcuColor & AcuMotion. Default gamma in User mode is set to 2.2 and I left it there. Pre-calibration measured an average of 2.30 with 70-90IRE reaching around 2.4. After calibration I was able to flatten out the high end a bit and achieve an average gamma of 2.18.
Average Gamma Pre-Calibration: 2.30
Average Gamma Post-Calibration: 2.18 (target 2.20) @ 2334 Lumens
White Balance calibration settings for Day mode.
I did not do a separate 4K/HDR calibration on the VL7860. All of the modes have an HDR option that is engaged when fed an HDR signal. There are 4 HDR settings, each one brighter than the next. Most times projector manufactures will disable gamma when HDR is enabled but not in this case. You are free to mix ‘n’ match gamma and HDR presets. I found that a gamma set 2.2 and HDR set to 2 or 3 yielded the best results with most content. Although using User Mode with Brilliant Color on will be a little brighter 4K/HDR picture, I prefer the more accurate slightly darker image from Rec.709 mode.
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