Pages: [1]   Go Down

Author Topic: rgb or cmyk  (Read 1954 times)

pulley

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 81
rgb or cmyk
« on: March 04, 2009, 06:56:10 pm »

I use Coreldraw exclusively and print to a Z2100. Should I be designing in RGB since I don't have a RIP and since the printer prints in RGB?
Would there be any considerable difference if I send a cmyk file to be printed instead of a rgb file?
Logged

Ernst Dinkla

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 4005
rgb or cmyk
« Reply #1 on: March 05, 2009, 06:52:50 am »

Quote from: pulley
I use Coreldraw exclusively and print to a Z2100. Should I be designing in RGB since I don't have a RIP and since the printer prints in RGB?
Would there be any considerable difference if I send a cmyk file to be printed instead of a rgb file?


It is more complex than what you describe. The printer in the end uses CMYK inks. The color management of the normal HP Z2100 driver is however in RGB-device style. I think you better use an RGB color description of all the work done in CorelDraw: Vector, Fonts, Images. AdobeRGB as the workspace in Coreldraw will be enough for the Z2100.
The practical side: load a big RGB color target (say 1800 samples from another profile creation program) in the application of Coreldraw that you use mainly. Assign AdobeRGB to that target. Print it with the color settings you use in CorelDraw + the correct ICC Printer Profile for the paper you will be using + relative colormetric/BPC rendering and print that target. If you are unsure next time about a Pantone color on that paper you compare your Pantone swatch book sample with a sample on the printed target and check the RGB numbers in the target file you printed it with then use the same RGB numbers in the design. Using relative colormetric/BPC rendering is a compromise between more accurate vector color and acceptable image printing. I'm not that familiar with CorelDraw anymore but if it has separate rendering choices for vector, fonts versus images then use the most suitable rendering choices for both when printing your designs but make sure that target which is an image file will be printed with the rendering choice you will use for vector art later on. I think that your Coreldraw must have better color management than the version 9 that I used many years ago. And using Pantone tables with RGB numbers is always a bit risky.
There's little against designing in RGB, it is in a way more futureproof than designing in CMYK. For output to web pages you should convert the original design to sRGB but keep the original in AdobeRGB. For output to offset printers either use a conversion to the profile provided by the printshop or let the printshop handle it in their CM or if there's no printshop CM to talk off take one of the generic profiles like SWOP. As it will be another paper and inks there will be a difference to what you printed on your Z2100. If it has to be absolutely correct in that case then there is no other choice than using a more complex process with your printer profile and the shop's profile. I'm sure someone will jump on this.


Ernst Dinkla

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/
Logged

pulley

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 81
rgb or cmyk
« Reply #2 on: March 05, 2009, 08:43:42 pm »

Thanks Ernst.

I am not using my printer for photo work, mainly signage and posters, so for the most part, color doesn't have to be an exact match. What I have done, is priinted a rgb color chart from Corel X4 on the chosen paper and vinyl with proper profiles. When a customer has certain pantone colors they need, I take the pantone chart and compare with my printed chart. Not exact color reproduction, but close, and this is explained to the customer ahead of time. Sort of like a cheater system, but I believe a lot of sign shops use this procedure, especially the ones without proper hardware calibration and printer profiles.

Again thanks Ernst for your insightful info.

Wes
Logged

digitaldog

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 20630
  • Andrew Rodney
    • http://www.digitaldog.net/
rgb or cmyk
« Reply #3 on: March 05, 2009, 09:00:27 pm »

Quote from: pulley
I use Coreldraw exclusively and print to a Z2100. Should I be designing in RGB since I don't have a RIP and since the printer prints in RGB?
Would there be any considerable difference if I send a cmyk file to be printed instead of a rgb file?

These drivers expect RGB data to produce a proprietary CcMmYkk (or whatever number of inks) used. If you send such drivers CMYK, they conduct their own internal (and not good) RGB conversion. So unless you're trying to simulate a CMYK process, and you have a RIP or driver that operates understanding CMYK, you really really want to send RGB data to these drivers.
Logged
http://www.digitaldog.net/
Author "Color Management for Photographers".

neil snape

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1447
    • http://www.neilsnape.com
rgb or cmyk
« Reply #4 on: March 06, 2009, 01:28:35 am »

No reason not to make a rgb profile for your media then send the printer either rgb (preferrably) or CMYK which will be converted with less precision than rgb.
This is the advantage of the Z printers, the built in profiler which makes an easy attempt to get closer print matching.
Logged
Pages: [1]   Go Up