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06/12/2004 03:12:46 PM · #1 |
When I joined this site I couldn't see anything. My monitor was very dark, and I didn't even know it until, while browsing past challenges, I came across this photo by amonteforte
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A lot of the comments were talking about the doors in the background -- and I could not even see them. To me it was a nice solid black background.
Well, I got busy; did the searches, found the sites and calibrated my monitor to a 2.2 gamma. It seemed so bright to me I found myself squinting at times, but I quickly got use to it. I found that each of the calibration sites generally arrive at essentially the same calibration ... but that calibration is still too dark for DPC!
Yesterday I was checking the calibration and found that the new bulbs in the room were a different temperature than what I had been using, so I went back to scratch and recalibrated. I started by fixing the white balance of the screen (temperature), which went from a 6300K to an 8300K before it looked right. Then, just to see if there was a difference, I used the PS curves method of setting the black point.
If your not familiar with this method, you can find it here (it is method #2 under black point). It recommends using a difference of 5 or higher to set the black point. I set it at five and found it produced the same results as the other methods.
Unfortunately I have never been completely satisfied with the results of the other calibrations (or this one) as they all seem to leave the last two boxes of the white to black scale at the bottom of the voting page very close to the same. There is some difference, but I have to really look to be able to see it.
I was curious if I could get a better distiction between the two (without using it specifically as the test chart), so I set the curves to a one instead of a five or better and recalibrated. I had to top out the brightness and then drop the contrast to get it balanced, and then play with it and the gamma to get it at 2.2, but now it is.
I am finally getting to the question. I can see distinctly each square in the scale on the voting page, I can even see an even, distinct, noticable change for each and every one of the 256 steps on the curves adjustment. The colors are all vivid and distinct, and in general the contrast and depth of the photos I have looked at since have been great. But... when I look and compare with the charts on the calibration sights (particularly the black level bands on this one) they all indicate my monitor is too bright.
I had to get really bright before I was able to see the difference between the last two squares with the same degree of seperation as the rest of them. So, are DPC standards for brightness higher than anywhere else?
David
/edit: clarity.
Message edited by author 2004-06-12 15:19:32.
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06/12/2004 05:55:41 PM · #2 |
When I look at those charts on my monitor I can differentiate correctly for the gamma that I have set.
When I look at the DPC scale, I can also differentiate each of the blocks.
My monitor is calibrated with a colorvision spyder and it is a ViewSonic professional series PF790, in a room lit with natural (and indirect) light.
For what it is worth, some monitors are incapable of being correctly calibrated, beyond a certain tolerance. Also, if you are judging with your eye it can be very hard to differentiate while avoiding the natural compensation that your eye does (which is one of its main functions after all, to ignore just the very kinds of variance you are trying to percieve)
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07/16/2004 05:15:05 AM · #3 |
A month later I stumble upon the answer to my own question.
Below I have placed the DPC contrast scale on various backgrounds (note that only the background changes in each of these, the scales are identical).
Notice the apparent change in the relative brightness between the three scales? This is a result of our eyes adjusting for the brightness of the area we are looking at -- with the resulting change in perceived brightness of everything else.
DPC standards aren't brighter, the relative bright background makes the darker end of the spectrum appear to be darker.
David
So yes, your photo may actually be perceived to be darker just by being viewed on DPC. :p
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07/16/2004 05:35:31 AM · #4 |
I have had so many comments on the words challenge that there are no words in my photo its not funny. I had previously calibrated my monitor using different methods found here and discovered just how far out it really was.
Because of the comments I decided that I must have stuffed up somewhere as the words while dark are clearly visable on my monitor. So I re calibrated again today with minor changes mainly in the gamma and it really has made little difference to how the photos are viewed.
I'm very glad but at the end of the challenge I'm going to ask someone who has the spyder (maybe you if you don't mind Gordon) to have a look at the shot for me and tell me if it really is to dark or if the other viewers have their monitor set to dark, at least that way I can message them and make them aware of their problem or fix mine if something is wrong here.
Bob
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