On Monday 22 July 2002 5:14 pm, Billy Biggs wrote: | Vadim Plessky ([EMAIL PROTECTED]): | > On Monday 15 July 2002 10:12 pm, Owen Taylor wrote: | > > > > If you do a web search you should be able to find some gamma | > > > > test patterns; you can then play around with 'xgamma' until you | > > > > have a gamma of 2.2 and see if the screenshots look better. | > | > Can you pls provide URL for the patterns which are the best, according | > to your taste? And what do you mean under "screenshots look better"? | > I think it's very subjective - wether screenshot looks better or not. | > Any way *to measure* and return back some alpha-numeric value, | > indicating wether gamma is o.k. or not? | | You can measure the gamma of your device using a photometer or similar | device. Unfortunately, the cost might not be justified in your case. | That leaves you to perform empirical measurements.
Yes, I am not going to buy photometer to correct gamma :-) | | Here's one I just found: | http://www.graphics.cornell.edu/~westin/gamma/gamma.html | | However, that only shows test patterns generated from a simple first | order approximation. It does describe some of the problems in testing | gamma. One of the problems I've found is that a CRT at high resolutions | usually does not have a fine enough grid to resolve individual pixels | correctly, causing strange blurring effects. I recommend testing CRTs | at a low resolution, say 800x600 or 1024x768, for best accuracy. In my case, I have LCD (TFT) display, part of my notebook (not CRT!). Any special suggestions for it? | | > > Something like: | > > | > > xgamma -gamma 1.2 | > | > I tried it with my system, I see changes on screen. So I guess my ATI | > Rage Mobility+LCD is supported. Not sure, though, what should be | > final result. | | It's probably best to calibrate your monitor for the sRGB standard: | http://www.srgb.com/ This means you should correct your monitor such | that it mimics the sRGB gamma of 2.2. Your digital photos, DVDs, and | other pictures will then (theoretically) look more correct. ok, thanks, I will try!.. | | To do this, you first find an approximation to your gamma curve by | finding one of these test patterns, measurement, or what not. Say your | display device is best approximated by a curve with an exponent of 2.6. | You then find the correction to get from 2.6 back to 2.2. In this case, | the correction is 2.2/2.6 == 0.84615. Run 'xgamma -gamma 0.84615' and | all is well. | [...] -- Vadim Plessky http://kde2.newmail.ru (English) 33 Window Decorations and 6 Widget Styles for KDE http://kde2.newmail.ru/kde_themes.html KDE mini-Themes http://kde2.newmail.ru/themes/ _______________________________________________ Render mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/render
