Dear Jan-Peter, Dear others, maybe you help with this additional information: I tried to use lcms transformation directly on the image (GWorld). I did so, and get the same bright image. Then I tried to use all three profiles in once (intern->proof->intern) instead of two time changes (intern->proof, proof->intern) and the image get much darker!!! than the orginal Image.
I use cmsCreateMultiprofileTransform to create the Transform, and use cmsDoTransform to use it. I tried all 4 RGB spaces (with 32 bit), as I expected the TYPE_ARGB_8 seem to be the correct one. Where came those brightness changes, and how could I prevent them (Mac, OSX 10.4.3, Dual G5 non-Mach-O Compile with Codewarrior 8.8) I did try 1.14 and the current beta of 1.15. thanks, Kristian Kratzenstein Kristian Kratzenstein on Montag, 31. Oktober 2005 at 19:04 +0100 wrote: >Dear Jan Peter, > >this is the case. I use Colorsync in the workflow (which is a full >in-memory workflow), but need blackpointcompensation. So I like to use >lcms for the conversion (or in this case the device linked profile). >I do not embedd any profile to the rgb data, so I do not add any device >linked profiile to the image. I'm fully aware of the problem with using >wrong profiles. The display on the screen is done once without any >additional conversion, or with conversion internal -> monitor. both with >same result.0 >As I told : It works create with transformation done by colorsync with >the same profiles. But when the transformation is done with the device >linked profile made by lcms I get a wrong gamma in the Image. This is >additional, when I use two device linked profiles in a row, the gamma is >added twice or more. >I hope this made the situation clear. > >kind regards, > >Kristian Kratzenstein >[EMAIL PROTECTED] on Montag, 31. Oktober 2005 at 18:42 +0100 >wrote: >Hello Kristian >If you do a standard ICC-transformation with colorsync, e.g. >input->printer, the destination-profile (printer) is embedded in the >transformed file. Using the application preview for viewing the >transformed file, the profile-chain is now printer->monitor. > >If you are making a transformation with a devicelink-profile, it makes >no sense to embedd the devicelink-profile, because it can´t be used for >viewing at the monitor. >If you made e.g. a devicelink-profile input-printer, you must embedd the > original printer-profile (not the devicelink) after transformation, to >compare the result with the standard ICC-transformation. > >As this is a second step, the usage of devicelink-profiles makes only >sense, if you use special options (like preserve black generation), >which are not available for standard ICC-transformtions. > >:-) Jan-Peter > > >Kristian Kratzenstein wrote: >> Dear Jan-Peter, >> >> I don't use any of this linked profile irectly to show on screen. This >is >> done with Quartz, and this get the device profile of the output device >for >> drawing. The calculation are done in memory. >> Before I did use Colorsync for (Input -> Printer) and (Printer -> Input) >> for proofing, that works well. Now I try to use LCMS for creating device >> linked profiles out of both calculations. The drawing on screen is not >> touched, the screen profile / rendering not changed. >> When I use both calculations at once (needed for proofing), the Image >get >> real bright. when using only one (lucky, the printer profile is also >rgb) >> the Image got also brighter, but not that hard. It looks like there is a >> gamma in every linked profile, which is added in each step. >> In addition : when I use absolute colormetric, the Image become also >> bright. >> >> kind regards, >> >> Kristian Kratzenstein > > > >-- >-- > >homann colormanagement ------ fon/fax +49 30 611 075 18 >Jan-Peter Homann ------------- mobile +49 171 54 70 358 >Kastanienallee 71 ------- http://www.colormanagement.de >10435 Berlin --------- mailto:[EMAIL PROTECTED] > > > > >-------------------------------------------- >Kristian Kratzenstein >Gettorf > >[EMAIL PROTECTED] >-------------------------------------------- -------------------------------------------- Kristian Kratzenstein Gettorf [EMAIL PROTECTED] -------------------------------------------- ------------------------------------------------------- SF.Net email is sponsored by: Tame your development challenges with Apache's Geronimo App Server. Download it for free - -and be entered to win a 42" plasma tv or your very own Sony(tm)PSP. Click here to play: http://sourceforge.net/geronimo.php _______________________________________________ Lcms-user mailing list Lcms-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/lcms-user
