klein@kira.uucp (Jeffrey Klein) (03/09/91)
I'm looking for a way to convert three-color printing to RBG values. Yeah, I suppose it all depends on what inks you use - specifically, I'm looking for a formula that will reasonably match the colors used in most letterpress comic books. --JK
meg8817@isc.rit.edu (M.E. Gorzynski ) (03/14/91)
In article <1991Mar8.160736.677@msuinfo.cl.msu.edu> klein@kira.uucp (Jeffrey Klein) writes: >I'm looking for a way to convert three-color printing to RBG values. >Yeah, I suppose it all depends on what inks you use - specifically, >I'm looking for a formula that will reasonably match the colors used in most >letterpress comic books. > >--JK The problem you pose is basically one of color reproduction between two different types of media. The method you choose to handle this depends on many factors. Perhaps the most important question to ask yourself at this point is "How much work am I willing to go through to achieve the level of quality I desire?" Easy solution, medium to good quality: Use a calibrated graphics system (employing something like TEK HVC, etc.) We've all seen ads describing software (especially for the MAC) which claim some level of device independent color reproduction capaility. These packages are beginning to include transforms for scanned imaages and various CRT displays. PRO: they've done the work CON: $ Easy solution, medium to very bad quality: Make some major assumptions and use a simple color model. Examples for original data in CMY include 1. Neugebauer, 2. (R=1-C,G=1-M,B=1-Y), etc. Hard solution, great quality: Using a colorimeter or spectrophotometer, measure a set of standard colors in both media. Next optimize a colorimetric color reproduction system using a device model or look-up table. This means that you will be able to predict the color coordinates of the reproduction based upon the original. To go further, you might investigate methods to improve the match using more advanced color appearance theory. The third (hard) solution obviously could be discussed in much more detail. This could include CRT models, printers, interpolation, etc. etc. I'm not sure this is the proper place for detailed color reproduction discussions. ------------------------------------------------- Mark Gorzynski, Munsell Color Science Laboratory, RIT meg8817@ultb.rit.edu -- ____________________________________________________________________________ Mark Gorzynski meg8817@ultb.rit.edu (129.21.201.2) Munsell Color Science Laboratory Center For Imaging Science, RIT