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I have followed the instructions on the main website (that I could find, thats one huge page) and managed to get my Spyder5 working, but I am having great difficulty getting the two monitors I use to calibrate correctly.
I have two Dell U2412M monitors running out of a GeForce GTX 960 graphics card, one monitor is about one year older than the other. The new monitors appears to calibrate correctly, but the older one has a distinctly warmer colour to it. What I am trying to achieve is a similar colour and brightness output on both.
How do I go about achieving this using DisplayCal?
All help is greatly welcome and appreciated.
This question comes up from time to time, you can search the forum for existing discussions. Generally, if the monitors are really identical (not only same model, but also same panel – manufacturers may use similar but different panels even within an exact model series), then the difference usually comes down to a visual whitepoint difference. If you can’t get the monitors to match by calibrating to the same whitepoint target, then you can match them visually by picking one monitor as reference and adjusting the other monitor’s whitepoint to match the reference. You need to set a whitepoint target of “As measured” for the monitor you’re trying to adjust for this to work.
Hi Florian,
thank you for the reply. I have run through the calibration for both monitors now a couple of times with white point set to “as measured for both” and the difference still exists. A few questions I have:
- by white point target do you mean the white square that pops up during the interactive display adjustment?
2. By visually matching do you mean compare each with my very own eyes and play around with settings on the one I am trying to match?
- & 2.
Yes and yes. It may help to have a fullscreen white or 50% gray (R=G=B) desktop background (and little else) while attempting this.
Ok, moving on logically in my mind, if I have to visually match the white point of one screen then what use is the actual colorimeter and how do I know it has actually calibrated the monitor I am trying to make an adjustment from? Surely the whole point of the software and the hardware device is to match against a given set of values (for me as close to actual white as possible) so adjustment does not have to made manually?
Surely the whole point of the software and the hardware device is to match against a given set of values (for me as close to actual white as possible) so adjustment does not have to made manually?
Each human has a slightly differing way in which they see color. An instrument converts light to frequency, and from there to tristimulus values (which are necessary for colorimetry) by virtue of color matching functions (CMFs) that are modeled after a standard (average) human observer (derived from measuring and averaging the CMFs of several observers). For that reason, even if an instrument “sees” a certain light stimulus as producing the same color, there may still be visible differences for a human observer. These differences mostly become apparent along and near the neutral axis, because humans are less and less sensitive to these differences as colors become more saturated. That’s why matching the whitepoints is usually enough to greatly improve the apparent visual match between different displays.
It should also be noted that consumer devices often do not (and potentially cannot, given their low cost) provide a level of accuracy that is as high as that of lab grade equipment (which can cost several thousand up to tens of thousands).
This mostly affects colorimeters, because they use gelatine or glass filters to simulate a standard observer. If the filters are a good match to the standard observer color matching functions, a visual match among different displays may be more easily attained than if the instrument’s filters were of lesser quality.All that said though it is important to keep in mind that this only becomes an issue when doing visual comparisons between different displays that are in view at the same time. To put it simply and leaving out finer details, the human visual system perceives color in a white-relative manner, the absolute white point does not matter so much as long as the eyes are adapted to that particular white. That’s why you will still see a white sheet of paper as white even if you shine a blueish (or reddish, greenish…) light on it (after some time of adaptation), for example. When you have two (or more) possible sources of “white” within your view, the human visual system doesn’t have a clear white reference anymore, and thus visual differences can become very apparent at that point.
