measuring monitor brightness with lightmeter

Discussion in 'Digital Darkroom' started by test1, Jan 6, 2009.

  1. Hi,
    I'm thinking of buying a colorimeter, but first would like to ensure that my 4 years-old monitor can still deliver required brightness. Using incident light meter (Sekonic 308B with lightdisk attached) I've got EV 5.5@ISO100 directly at the monitor surface that was filled up with white (255,255,255). According to the Sekonic documentation that corresponds to 110 lux. The higher models of sekonic allow measurements directly in cd/m2 mode, but my lightmeter doesn't have it.
    Is there some method to correlate that lux value to cd/m2, in which monitor brightness is usually described?
    Kind regards,
    iLya
     
  2. According to a convertor at http://www.unitconversion.org/illumination/lux-to-candela-steradians-per-square-meter-conversion.html it is equal to 110 cd/m²

    Roger
     
  3. You need a monitor calibration system regardless of whether your monitor gets up to proper brightness or not. If it's not bright enough to calibrate you just also need a new monitor. If you get a new monitor you still need a calibration/profiling tool.
     
  4. Guys,
    thank you for your quick replies. I know that I'd need a new monitor if my is not up for the task, but in that case my first priority would be getting a monitor, and calibration system would have to wait perhaps another year.
    The formula mentioned in the link converts from lux to candela steradian per sq. meter. This sounds like cd*sr/m2 not just cd/m2. I'm confused. Also, is it correct to measure with meter in incident mode or should I remove attachment and measure screen as it would have been reflective surface? In later case I get over EV 9@ISO100.
     
  5. i would then wait for both..or get a monitor and pray until then to get good result; you NEED both to acuratly know what you are printing, without it your kind of color blind ; )
     
  6. A monitor without a calibration device is of limited usefulness.
    If you're in the states, try Craigslist- CRTs are going for next to nothing. You can calibrate a monitor that gets down to the 80 cd/m2 (actually I prefer low brightness for photo work).
    I don't think you'd use incident mode to measure a light source- doesn't that just tell you how much light is falling back on the meter rather than what the light source is putting out? If your monitor is still reasonably bright and doesn't have a distinct color cast (i.e. no red and pumping up the red in picture controls doesn't fix it) I'd think you can calibrate it.
     
  7. jtk

    jtk

    You don't need to "know what you're printing." You can make test prints and adjust accordingly unless the monitor is wandering all over the place.
    This is exactly what traditional wet darkroom printers have always done...they use their eyes.
    Many did formal "color ring-arounds" (browse "color ring-around printing) until their color skills became highly developed.
    http://www.ephotozine.com/article/Making-a-colour-darkroom-ringaround-chart
    The technique is virtually identical in highly organized B&W darkroom printing workflow.
     
  8. John, what the point of doing 2-3-4-5 test print that cost 2$ each ..when people already complain that printing at home cost too much?! Why dont you just use a device to calibrate your monitor and be set EVERYWHERE..not just at your place or at your favorite photo lab.
    Doing *the test print method* will only be good for a certain amount of time, and only if you always print at the same place..and all is to be done again if you print elsewere...
    You can fight the idea of color management, figth the idea of calibrating your monitor, but that is the sad thrut; until you did exactly that you will be making test print all the time and trowing $ out of the window like all the young amateur i know that keep complainig about the *why my print are too dark vs my monitor*.
     
  9. Thanks all for responses! Kent, link was very useful and that page itself has links to other useful info regarding calibration.
    I've found documentation on my monitor and it states that in normal mode it's max brightness is 95 cd/m2, and 300+ in some high-brightness mode (could be it's that picture/video modes which I didn't like). And according to my measurements with lightmeter I'm getting about that. Few days ago visited local pro-lab and guys there were very nice to show their equipment among them monitor similar to mine just 22" instead of 19" and assured that if their much older is still capable of being calibrated then mine with only 2-3h/day usage should be fine too. So now I'm more or less settled to get the colorimeter.
     

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