Am 06.03.2007 um 22:44 schrieb Hal V. Engel:
> On Tuesday 06 March 2007 10:11, Dwain Alford wrote: >> i have been mystified by color management for years. all of this >> profiling >> for different papers, inks, printers. well at last i have come >> upon a >> system that works for me and it didn't cost any money profiling any >> hardware of for paper. >> >> most non postscript printers render i rgb, regardless of how many ink >> cartridges you have to install. all of this monitor calibration i >> have >> found is bunk as well. and as for paper, well, i use what ever i >> want and >> still get a good print with the expected results of ink absorption >> with >> certain papers and the finish of the paper (read: photo). >> >> i have an epson stylus photo 1200. it has a black cartridge and a >> 6 color >> color cartridge. > > The 1200 series has 6 inks total including the black cart not > seven. Probably > a typo. > >> i have fought with getting what is on the screen to the >> paper since i have had it, but i finally figured it out. >> >> now i am on a windows os, so your installed profiles may be >> different, but >> i do believe that the srgb color space (same as srgb iec61966-2.1) is >> available on all operating systems. one other note, kodak and hp >> offer a >> srgb iec61966-2.1. in fact, on my system, the srgb color space >> profile is >> from hp and the srgb profile is from kodak to be used in a d65 >> monitor set >> up with a gama of roughly 1.8. > > sRGB is an approximation of a monitor calibrated to gamma 2.2 and > D65. Not > gamma 1.8 which is a now long obsolete Mac standard. In addition, > most CRTs > have a native gamma between 2.3 and 2.5 so even sRGB will be > incorrect for > most CRTs. Sorry to intervene here but I thought gamma 1.8 is a defacto standard for prepress monitor devices, isn't it? >> when available i set my graphics software (all of them) to srgb >> iec61966-2.1for the rgb color space. i use the swop v2 setting for >> cmyk (this setting >> depends on the color profile of your commercial printer, match it and >> you're in heaven, nirvana, elysian fields or any other good place >> you want >> to be). inkscape uses a flavor of srgb iec61999-2.1. >> >> now for the hardware. i set my printer to the srgb color space >> profile. > > As you point out above you are on Windows. On Windows the system > default > color space is sRGB and all devices (printer, video...) using the > default > driver settings are supposed to be sRGB. This of course is not > always the > case (in fact it seldom is) and users who understand color > management do not > use the default driver settings for printing in their color managed > work > flows. Why? Because in the default mode the drivers do all sorts of > automatic stuff that make them unsuited to a color managed work > flow. That > is the results are unpredictable unless all of the automatic > trickery is > turned off. > > If you go to the Epson download site you can get a set of profiles > for many of > the Epson printers including the 1280/1290, R2400, R1800, > R800..... I don't > know about the 1200 but you might want to check. In addition > there is a > manual that is part of the download that describes how to use these > profiles. > That manual says to use the no color correction mode (IE. turn off > all of the > automatic stuff) when using the supplied profiles. In addition the > manual > has very detailed instructions on all of the settings to be used in > the > driver with the profiles. These profiles are paper and printer > specific and > are only valid with the specific Epson papers used to create the > profiles. > These are Epson's directions on how to make color management work > with their > printers not mine. So please have a look. > > One other thing to point out is that even though modern ink jet > printers like > the Epson 1280 and R2400 have a limited somewhat smallish gamut the > gamuts of > these devices have a significantly different shape than the sRGB > gamut and > there is are significant parts of the gamuts of these devices that > fall > outside of what can be represented by sRGB (yellows are the worst > case). > That is you will be getting either clipping of what would otherwise > be usable > colors or you will be incorrectly printing some colors if you treat > these > devices as sRGB devices. The gamuts of these printers are also > significantly larger than your typical offset printer so profiles like > ISOCoated are not correct for these devices either. > >> now you can go to http://www.color.org and down load icc >> profiles. there >> you will find the srgb profile mentioned above one with and one >> without >> black point settings. read the difference between the two. i >> have used >> them both, but for the hardware i have i stick with the srgb color >> space >> profile. >> >> my microtek 5900 scanner is set to srgb iec6199-2.1 > > Why? It is easy and inexpensive to create custom profiles for your > scanners > and cameras. For flat bed scanners all you need is an ($15 + > shipping) > IT8.7/2 target from Wolf Faust, LProf or ArgyllCMS (Lprof is easier > to use > and both are open source and free), and a few minutes to scan the > IT8/7.2 > target and process it into a high quality custom profile. Both > pieces of > software will create world class input device profiles. If > correctly created > these custom profiles will definitely be better than using sRGB for > your > scanner. As an example raw processed images from my DSLR have a > gamut that > is almost twice as large as sRGB at almost 70% of CIELab. There is > no way > that I could use sRGB for this device and not either loose (clip) or > misrepresent almost half of the devices available gamut. I should > also point > out that the IT8.7/2 target itself actually has a gamut that is > larger than > the sRGB gamut and most scanners will be able to capture the full > gamut of > the target. > >> and so is my monitor, >> but the colors are sometimes off, what to do, what to do? >> >> here comes the tricky part, the monitor settings. i have seen >> them all. >> some go to yellow side (d50) and some go to the blue (d93); but as >> for me, >> i want a neutral setup. i took the chance one day and did the user >> settings to adjust my monitor. >> >> now i come from a photographic background and understand a little >> about >> color and color correction. since i wanted a neutral setup that >> would >> render a print as close to what i had on my monitor i had to make my >> monitor neutral, thus the need for the user defined color settings. >> >> i took a deep breath and set the r,g & b to 50%, and made a >> print. now >> remember all of my software and hardware carry the same srgb and >> cmyk color >> profiles. when i viewed the print, it was like a miracle, but it >> didn't >> match my monitor. the print was lighter than my monitor. i saw >> all of the >> detail and color that i was supposed to, the brightness and >> contrast in the >> print was where i wanted it, but it didn't match my monitor. so i >> turned >> up the brightness on my monitor to match, as closely as possible, the >> density of the print. >> >> viola! i was in synch hardware and software wise for the first >> time since >> 1999. but did it really work outside my environment? i write a >> basic >> computer skill column for a local weekly newspaper. i sent them a >> black >> and white print. looked like it did on my monitor. but what >> about color? >> i had done some business graphics for my nephew's business. we >> made his >> business card and had it printed, from a pdf (although not a >> scribus pdf) >> and the colors came out like on my monitor. > > OK you think your monitor is now correctly calibrated but is it > really? Since > you are a Windows user (same is true for Mac users) you can shop > around and > purchase a Pantone Huey for about $50 + shipping (look on ebay). > This device > and the included software will allow you to calibrate and custom > profile your > monitor(s). I think you will be surprised at how much better all > of this > works with a hardware calibrated and profiled monitor. I know that I > thought that my visually calibrated monitors were pretty close but > I was > shocked at how much better they were after using a hardware > measurement > device to calibrate and profile my monitors. For Windows and Mac > users the > cost of getting the hardware and software to do this is now so low > that there > is absolutely no reason for any Windows or Mac user who is doing color > critical work to not have this type of device and software. > > One other point about hardware calibration. Even with this > hardware and > software to guide setting the monitor controls I can get the white > point to > be very good with a delta E of less than 1.0 (very small error level) > relative to D65 but at that setting my black point is off by a > delta E of > about 16 (large error level). Which means that my average delta E > along the > black locus (the neutral tones) is about a 7 or 8. At that point > the monitor > is more neutral than I have ever been able to achieve using visual > techniques. Then running a hardware based calibration and loading > the video > LUT with the resulting data corrects the black point problems and > results in > an improved average delta E of around 1.0 with a peak of about > 3.0. In > addition the display gamma goes from 2.53 before LUT loading to > 2.24 (nearly > perfect) after the LUT is loaded. Overall the amount of > improvement in the > display calibration and neutrality is striking. Having used both > visual and > hardware techniques for this I can tell you that with the low cost > of getting > the hardware and software these days that I can no longer recommend > using > visual techniques to anyone who is doing color critical work. > > When I do color critical work on Windows I use profiles provided by > my paper > vendor for my printer. In my case this is the Illford Galleria > Smooth Gloss > paper profile for the Epson R2400. The results are very good and > even more > important totally predictable. It might be possible to get > slightly better > results with a custom printer profile since like all mechanical > devices these > printers do have sample to sample variation. In addition when I > send images > out to printing services that have good color management work flows > the > results I get back are an excellent match to what comes out of my > Epson > printer and to what I see on my display. > > So for Windows and Mac users you can get setup to do input device > (scanners > and cameras) profiling and hardware based monitor calibration and > profiling > for less than $100. You can also get free profiles from most paper > vendors > for most currently produced color printers. This will allow you to > setup an > end to end color managed work flow that will give you consistent > totally > predicable results. > > Hal > _______________________________________________ > Scribus mailing list > Scribus at nashi.altmuehlnet.de > http://nashi.altmuehlnet.de/mailman/listinfo/scribus >
