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Old 04-06-2001, 11:29 AM
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Exclamation How does BESTColor handle Black Generation?

In Best's internal color management the Black Generation is handled by the paper profile. For that reason you can control the black generation only in your profiling software.

Last edited by UlfG : 04-06-2001 at 11:57 AM
  #2  
Old 04-06-2001, 12:06 PM
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Lightbulb Why do you need a base linearization?

The base linearization is the first step in the profiling workflow. During base linearization you set the gray balance and the dot gain in consideration of the inkjet printer and paper you use. The base linearization works directly with the printer and is independent from Best's color management.

The base linearization is based on color densities. You can control the gray balance by changing your 100 percent densities. (You can control each channel for itself.) If you want a reddish gray, just use a higher density for magenta and yellow (and so on). We can give no rules for the settings, because ink / paper combinations perform too different.

Example:

A good setting for Epson SP5000 (measured with status E):
Paper: BESTSemiMatt 6180
Ink: Epson DYE Ink with CMYKcm
Resolution: 720 dpi
Dot size: fine
Densities: C: 1,65 M: 1,66 Y: 1,63 B: 1,69
Lab-Values: C: 52,56 -33,4 -56,26 M: 50,75 80,67 4,56 Y: 86,52 5,75 99,23 B: 15,32 3,55 1,04

BUT

a good setting for ROLAND FJ52 (measured with Status E)
Paper: BESTSemiMatt 8180 (for Pigment Ink)
Ink: ROLAND Pigment CMYKOG
Resolution: 720 dpi
Dot size: fine
Densities: C: 1,56 M: 1,46 Y: 1,34 B: 1,64
Lab-Values: C: 57,54 -41,33 -54,82 M: 49,12 79,39 -18,48 Y: 91,82 -7,13 100,08 B: 16,96 -,013 -1,72

If you have the chance to get the Lab values then evaluate them supplementary to the density-values. But which value from Lab is interesting? This depends on the color.
C: a-Value M: b-Value Y: b-Value

If you have too much ink on the paper the color will exceed its maximum saturation, and you will get non-steady Lab values (e. g. -45, -46, -43, -41, -38 for the cyan a value) which is a drawback for profiling. For profiling, a steady order of the numbers is desirable (e. g. -38, -41, -43, -45, -46). You can set each color channel separately during creation of your base linearization. (Per-color ink limit.)
  #3  
Old 04-06-2001, 12:11 PM
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Lightbulb How does total ink reduction work?

First: total ink reduction doesn't change the color separation, it only limits the ink.
What should you know?
If you set an per-color ink reduction during a base linearization, you can't reach 400 percent.
Example: Ink reduction per color was set to: C 60, M 75, Y 80, B 60. This adds to 275 percent total ink. Each total ink limit value higher than 275 percent will take no effect in this case. Now you set 180 percent Total ink inside BESTColor. Every color which puts less then 180 percent total ink onto the paper is not changed. Only colors which put more then 180 percent on the paper will be reduced to 180 percent. This way, you obtain the maximum gamut from this printer / paper combination.
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Old 04-06-2001, 12:14 PM
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What is the difference between base linearization and printer linearization?

Base linearization: describes the "working point" from Paper and Printer and Linearization of the Gray balance. Necessary for profiling.
The Baselinearization also includs the information about the Light, Medium and Norm Ink (this is the only information which is inside our Standard BPL-Files for creating your own BaseLin)). We call this Light/Norm Table or Light/Medium/Norm Table.

Printer linearization (should be called "printer calibration"): recalibration of the printer regarding its working point. This is a supplement to the base linearization and is only for recalibration of a printer that was base linearized before

Last edited by UlfG : 04-24-2001 at 04:51 PM
  #5  
Old 04-06-2001, 12:22 PM
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Lightbulb How does BC handle 6 or 8 inks?

CMYKcm:
The information about using light and norm ink for cyan and magenta is inside the base linearization. The user can't change this setting. BC uses all 6 inks for printing, but these 6 inks are basically handled like 4 colors CMYK.
CMYKccmm: like CMYKcm
CMYKOG: BC has an internal separation table for CY to G and MY to O
CMYKcmOG: CMYKcm and CMYKOG together

Last edited by UlfG : 04-06-2001 at 12:25 PM
  #6  
Old 04-06-2001, 01:13 PM
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Exclamation What is the difference between Inkjets with 6 Inks and 6 Colors?

In the field you have different Inkjet Printer Types. For Color Management we distinguish between:
4 Color Printer CMYK and 6 Color Printer CMYKOG, this has nothing to do with the numbers of Ink they use.
For example:
4 Colors and 4 Inks:
All this Printers use CMYK for printing and for each Color they have only 1 Ink
like:
EPSON Stylus Color 3000
HP Color Pro GA

4 Colors and 6 Inks:
All this Printers use CMYK for printing and they have only 1 Ink for YK and 2 Inks for CM (Norm and Light)
like:
EPSON Stylus Pro 5000/5500
HP Pro 5000
Canon BJC8500

4 Colors and 8 Inks:
All this Printers use CMYK for printing and they have only 1 Ink for YK and 3 Inks for CM (Norm, Medium and Light)
like:
Encad Pro850

6 Colors and 6 Inks:
All this Printers use CMYKOG for printing and they have only 1 Ink for CMYKOG
like:
Roland FJ50/52
Mutoh 4100/6100

6 Colors and 8 Inks:
All this Printers use CMYKOG for printing and they have only 1 Ink for YKOG and 2 Inks for CM (Norm and Light /Medium)
like:
Encad 850
Roland FJ 400/500


You need for different Color/Ink Combinations different BPL-Files in BESTColor !!!!!

Last edited by UlfG : 04-06-2001 at 01:33 PM
  #7  
Old 06-25-2001, 11:40 AM
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Dither Modes in BC

BC provides 3 different Dither Modes, depending on the Version.

standard: BC 1.xxx up to 4.2.3 (PC only)
enhanced: BC 4.0 up to 4.2.3 (PC only)
super enhanced: 4.1 up to 4.5 and BC DE

What is the difference?

standard:
this is the old dithering with 1 internal Lut for all Printertypes (1 for 4 Ink Printers and 1 for 6 Ink Printers )

enhanced:
improved dithering with 1 internal Lut for all Printertypes (1 for 4 Ink Printers and 1 for 6 Ink Printers )

With both modes you have no control about the independant Inkchanel. You can set the Inklimit/Chanel, but this takes effect on all 4 Colors together.
Example: Inklimit/Chanel to 90%, All 4 Colors (CMYK) have the limitation to 90%

super enhanced:
improved dithering with external Lut (BaseLin) for each profile

with the BaseLin you have full access to all Inkchanels and you can set each chanel for itself.
Example: C=60%, M=75%, Y=80% and B=60%
Now you can control your Graybalance from your uncalibrated print, which makes the profiling much more easy.
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