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Monitor Calibration contrast setting

Discussion in 'Computer Related Help & Discussion' started by dangie, Nov 20, 2018.

  1. dangie

    dangie Senior Knobhead

    I calibrate my dual monitors with a DataColor Spyder5 Pro.

    I do all the basic settings e.g. ambient light, monitor brightness, RGB settings as requested by the software. What I don't adjust though is the monitor contrast setting. The program doesn't mention it.

    Does the calibration take the contrast setting into account when creating the monitor profile?

    I ask because if I put a colour chart onto both monitors, the image on each is pretty identical. However if a put a snow scene for example onto both monitors, one monitor definitely shows more contrast between the whites and greys in the snow than the other monitor. Both monitors are Samsung, but different models.

    Thank you.
     
  2. PeteRob

    PeteRob Well-Known Member

    If you want two monitors to provide as close as possible the same image then indeed you need to set both the white point and the black point to be the same. The white point is set by the chosen brightness and colour temperature but often the black point used is the monitor native value. When I profile my NEC and my imac together the imac has the less black, black point so I usually choose to measure black point on the Imac then set it a tiny bit less black in calibrations for both. My NEC struggles with calibration in the dark greys with a Spyder 3 - I really ought to get a better instrument.

    I don't know the Spyder 5 pro software and whether it lets you measure/confirm the white and black points. I usually check my NEC which isn't a very bright monitor and takes about 30 mins to warm up. I'm using basiccolor Display 5 software (an old version, as newest doesn't support my monitor).
     
  3. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    The contrast setting is usually set by the Gammar you choose. probably 2.2 on basic displays
    though I use an X-rite display rather than a Spyder
     
  4. PeteRob

    PeteRob Well-Known Member

    You need to be consistent in how you get from the black point to the white point, so whatever the profile options chosen they do need to be the same. I can't remember what Spyder software does.
     
  5. Terrywoodenpic

    Terrywoodenpic Well-Known Member

    On the X-rite display You get a scale with a target point that you have to match by adjusting the monitor brightness. the Gammar you choose sets the desired contrast.
    The various test routines combined with the software, measures the colour levels and brightness of the grey scale points. which establishes the LUT for that monitor.
     
  6. PeteRob

    PeteRob Well-Known Member

    Sounds like it uses the native black point of the monitor then. I have to go through the calibration process to remember exactly what I do, as I have forgotten, but the black and white points are set, using a standard illuminant D65, or D50 for example. Then it uses L*a*b which I think is a linear contrast curve. I'll recalibrate tonight - it is long overdue!

    I was wondering whether to get an X-rite display or ColorMunki device as an upgrade on the Spyder 3 hardware. The Basiccolor Discus is still rather expensive although the price has come down: https://www.basiccolor.de/basiccolor-discus-en/. The software is https://www.basiccolor.de/basiccolor-display-5-en/ but I'm stuck on release 5.7.2 which is the last one that supports both my NEC P221W and the Spyder 3. These were discontinued sometime around May 2017 when NEC changed their monitor control software.
     
  7. GlennH

    GlennH Well-Known Member

    Gamma and contrast are a bit like curves and levels in Photoshop. A gamma correction affects the mid-tones of the image (contrast/brightness), while contrast alters the relationship between brightest and darkest parts of the image. Ideally, you should be able to [barely] discern the difference between 0,0,0 & 1,1,1 and 255, 255, 255, and 254, 254, 254.

    Terminology differs, but white point usually refers to colour temp (correlated colour temperature, to be more accurate) while white level refers to luminance.

    Control ambient light when editing instead of having a calibration device regularly measure it - not necessary. Avoid adjusting RGB settings if you can, since these reduce monitor gamut and increase the likelihood of banding and artefacts (same is true of gamma correction and white point - it's worth trying native settings).
     

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