Corel® Photopaint 9 has many, if not most of the tools for assisting in the preparation of press ready set of bitmap images for Scribus. Even if it is not your favorite image editor on Linux, it is the only one freely available having fairly full support for color management, as well as support for proprietary and spot color libraries, without spending a fortune for professional pre-press tools for Linux. As one who is a frustrated Corel Draw user preferring both Adobe's Illustrator on PC and Sketch on Linux, I approached Photopaint with a bit of trepidation.
I have been pleasantly surprised how capable it is for DTP. It is disappointing to learn it will no longer be ported with the winelibs for Linux. Included with Photopaint 9, is a version of the Kodak® color management system. While it is a bit older than the engine in Photoshop 6 and 7, its color work flow is very similar to Scribus/littlecms, as well as Adobe Pagemaker 6.5 / 7.0 on Win32.
Important features of Photopaint 9, which are useful for DTP:
One of the challenges in desktop publishing is the accurate conversion of RGB images colors to CMYK. Most printers have a narrower range of colors that can be replicated with 4 color inks on paper, than an RGB monitor or workspace. Here is a simple example of the process, using the first Scribus logo. Notice the orange outline of the pen nib above in the logo. We have originally opened this up as RGB .png file. Then we convert to RGB TIFF. First, set up the color profiles as close as possible with the same icc or try to use the same icm profiles used with the littlecms engine in Scribus. You can import the profiles from the
/local/lib/scribus/profiles directly into Photopaint. to enable
them for use with Photopaint.
Then, we set the option, View >Calibrate color for display, which is a bit misleading. We are actually telling Photopaint to adjust the screen's RGB display to mimic the CMYK "Gamut" or color range of our CMYK printer. By enabling this setting we then see, "out of gamut" colors which are displayed in lime green below. These out of gamut colors are not able to be printed on the selected printer or unwanted colors shift may occur.
Once it is converted to 32 bit CMYK, using a rendering intent of perceptual, it returns to a much closer and realistic, printable color. The screen to print results are an almost perfect match.
When printing from Scribus or Scribus created PDFs from Acrobat Reader at high resolution, it also important to remember paper quality and brightness also can affect the appearance of the colors,sometimes radically.
One important variable in the Corel Color Management system is the option for internal RGB. I would recommend trying the default internal first followed by Adobe RGB 1988 or Bruce RGB 1988. Bruce RGB, created by Bruce Fraser mentioned elsewhere, is a variation of the Adobe® RGB working space and is quite useful for general purpose images like photographs. I have used this with color photographs and I have been pleased with the results. Do not hesitate to experiment, as there is no one "perfect" way of converting colors.
Color Management, though it has been a part of professional pre-press for a while, is still a work in progress in desktop publishing and printing. A little experimentation will usually yield good results. Certainly, the real possibility of having a color managed work flow for DTP on the Linux desktop was but a wish several months ago...
One place to get profiles is from Corel. You will need to extract them using dosemu, from a command prompt in Wine or open them on a Windows PC, as they are self-extracting