Hi, I'm forwarding your question also to mailing list.
>My application is like this: >Suppose a container A is filled with liquid pigment BROWN (with > a certain LAB color value, taken from an RGB camera) >I have now a container B, filled with liquid pigment light-reddish-brown > color (with a certain LAB color value, different from that of pigment BROWN above) > > >Now, how can I: > Add and mix three (CMY) colors into container B, with the intention that the > resulting LAB value is the same as that of pigment BROWN in container A above. > > > Can I use your littlecms to calculate how much CMY I must add into B? Yes, you can. But note that you would need a CMY profile describing how the mixing behave. And obtaining this profile is not easy. Anway, assuming you got the profile, you need to create a transform Lab -> CMY Using this transform, feed the Brown Lab color. You will get one possible combination of C, M, Y pigments for A color. Call it CMYa Next, feed the transform with light-reddish-brown Lab, You will obtain the amount of C, M, Y for the B color. Call it CMYb Next substract the amount of pigment CMYb -CMYa. The difference would be the amount of pigment needed. For taking Lab color from RGB camera, you will need a profile of the camera as well. The transform is RGB -> Lab And finally, there is no need to use Lab values, since you can join both transforms in one. RGBcamera -> CMY That is, the transform will give you the amount of pigment from a RGB value taken directly from camera. Hope this helps, Mart� Maria The little cms project http://www.littlecms.com [EMAIL PROTECTED] ----- Original Message ----- From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, May 21, 2002 4:50 AM Subject: Question. Hi, I've searched the FAQs and mostly it describes image-related problems. I am looking for a single color point subject (one color pixel). My application is like this: Suppose a container A is filled with liquid pigment BROWN (with a certain LAB color value, taken from an RGB camera) I have now a container B, filled with liquid pigment light-reddish-brown color (with a certain LAB color value, different from that of pigment BROWN above) Now, how can I: Add and mix three (CMY) colors into container B, with the intention that the resulting LAB value is the same as that of pigment BROWN in container A above. Can I use your littlecms to calculate how much CMY I must add into B? If not, would you please direct me to the proper sources? I've searched the net and couldn't find the right source of info. Thank you so much for your help. Regards, Ted. _______________________________________________________________ Don't miss the 2002 Sprint PCS Application Developer's Conference August 25-28 in Las Vegas -- http://devcon.sprintpcs.com/adp/index.cfm _______________________________________________ Lcms-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/lcms-user
