Re : [Gimp-user] Monitor for Gimp
Le 29.03.2004 01:46, John Culleton a écrit : On Sunday 28 March 2004 04:15 pm, Jean-Luc wrote: On Sun, Mar 28, 2004 at 02:38:12PM -0500, John Culleton wrote: The best is to adjust the gamma within the Xfree software. There is an application called kgamma and a plugin for gkrellm to do such an adjustement. KGamma for some reason was not included on my LInux Slackware 9.1 system so I downloaded the Kgraphics 3.2 package and am compiling it as I write this. I had no luck with LProf and sent an inquiry to the authors. Whenever I tried to load a file it just quit suddenly with no error message. Is Gamma adjustable on monitors less than $1,000 US? In fact, you don't adjust the gamma of the monitor, you tune the window manager, the whole xfree or the application to match the gamma of your monitor. The gamma of the monitor is the transfer function of the electron beams of your monitor. It describes the non-linear relation between the pixel values and the monitor luminance. Luminance = (pixelvalue/255)^^gamma As an example, you will find attached what is such a transfer function for several value of gamma. General, the commonly admited value of gamma for PC is 2.2, the value for a MAC is 1.8 and a liear transfer function will gives 1. There is also an other setting you have to take care of: it is the colour temperature of your display. There is for most the display the choice of different colour temperature. The default value is 9500K which gives very cold colours (too much blue). This is perfect for office work. For digital photo processing a colour temperature of 6500K if available is more suitable. -- John Culleton -- Regards - Jean-Lucattachment: gamma.png pgp0.pgp Description: PGP signature
Re: [Gimp-user] Monitor for Gimp
On Sun, Mar 28, 2004 at 02:38:12PM -0500, John Culleton wrote: I find that my current monitor (Orion 17 inch OC-17DB0725) has adjustments for brightness and contrast but none for gamma. The venerable Gimp User Manual (GUM) offers instructions for making at least a crude Gamma adjustment. But my monitor has no such adjustment. and when I load the file recommended by the GUM I find that my monitor is at the high end of the scale for gamma. The best is to adjust the gamma within the Xfree software. There is an application called kgamma and a plugin for gkrellm to do such an adjustement. You can alsao use lprof to create a profile for your monitor. lprof allows you to have a separate gamma for each of the RGB channels. Then you can use this profile with the 'color proof' filter within the Gimp. Is there a monitor at a reasonable cost, a few hundreds of dollars, that allows for adjustment of gamma? Bearing in mind the limitations of Gimp in the color management area, what is suggested? I just want to get things close enough that what I send to the printer will bear some relationship to what I see on the screen in Gimp, allowing for (of course) the conversion to CMYK at some point. -- John Culleton Able Typesetters and Indexers http://wexfordpress.com ___ Gimp-user mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-user -- Regards - Jean-Luc ___ Gimp-user mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-user
Re: [Gimp-user] Monitor for Gimp
Hi, John Culleton [EMAIL PROTECTED] writes: I find that my current monitor (Orion 17 inch OC-17DB0725) has adjustments for brightness and contrast but none for gamma. The venerable Gimp User Manual (GUM) offers instructions for making at least a crude Gamma adjustment. But my monitor has no such adjustment. and when I load the file recommended by the GUM I find that my monitor is at the high end of the scale for gamma. You could use the gamma display filter to get gamma correction for free. With a little extra hacking, you'd get full monitor calibration based on ICC color profiles. Sven ___ Gimp-user mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-user
Re: [Gimp-user] Monitor for Gimp
On Sunday 28 March 2004 04:15 pm, Jean-Luc wrote: On Sun, Mar 28, 2004 at 02:38:12PM -0500, John Culleton wrote: I find that my current monitor (Orion 17 inch OC-17DB0725) has adjustments for brightness and contrast but none for gamma. The venerable Gimp User Manual (GUM) offers instructions for making at least a crude Gamma adjustment. But my monitor has no such adjustment. and when I load the file recommended by the GUM I find that my monitor is at the high end of the scale for gamma. The best is to adjust the gamma within the Xfree software. There is an application called kgamma and a plugin for gkrellm to do such an adjustement. KGamma for some reason was not included on my LInux Slackware 9.1 system so I downloaded the Kgraphics 3.2 package and am compiling it as I write this. I had no luck with LProf and sent an inquiry to the authors. Whenever I tried to load a file it just quit suddenly with no error message. Is Gamma adjustable on monitors less than $1,000 US? -- John Culleton Able Typesetters and Indexers http://wexfordpress.com ___ Gimp-user mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-user
Re: [Gimp-user] Monitor for Gimp
Hi, John Culleton [EMAIL PROTECTED] writes: KGamma for some reason was not included on my LInux Slackware 9.1 system so I downloaded the Kgraphics 3.2 package and am compiling it as I write this. Any text editor to edit your XF86Config would have been sufficient. But then, it's questionable if a general Gamma adjustment on the X server level is such a good idea at all. However if you are seeking for a monitor to do gamma correction, then setting the gamma adjustment on the X server is probably exactly what you want to do. Sven ___ Gimp-user mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-user
Re: [Gimp-user] Monitor for Gimp
On Sunday 28 March 2004 06:57 pm, Sven Neumann wrote: Hi, John Culleton [EMAIL PROTECTED] writes: KGamma for some reason was not included on my LInux Slackware 9.1 system so I downloaded the Kgraphics 3.2 package and am compiling it as I write this. Any text editor to edit your XF86Config would have been sufficient. But then, it's questionable if a general Gamma adjustment on the X server level is such a good idea at all. However if you are seeking for a monitor to do gamma correction, then setting the gamma adjustment on the X server is probably exactly what you want to do. Sven I learn something new every day! I have been diddling with XF86Config for years now, and I never used the optional Gamma parameter. On my particular monitor, with both brightness and contrast cranked up all the way, and using the gamma test file gamma.tif, the gray rectangle matches at about the top of the scale with the monitor at minimum zoom. Top of the scale is 3.0. So is this the setting I should use for Gamma in XF86Config? Or, given these results, is my monitor to far gone and do I need a new one? -- John Culleton Able Typesetters and Indexers http://wexfordpress.com ___ Gimp-user mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-user
