+PM5 UCR/GCR Settings -> How to achieve in i1Profiler?
Question: ProfileMaker 5 Software provided some UCR and GCR options to define the Black and CMY Generation Curves for CMYK output pofiles. i1Profiler does not include UCR/GCR1-4 selections anymore. How can I achieve analog UCR or GCR settings in i1Profiler?
Background: UCR (Under Color Removal) and GCR (Gray Component Replacement) are methods to replace amounts of CMY colors with Black. There are several reasons why it is advantageous to do so. UCR and GCR define how much of the CMY inks will be replaced with Black. The decision for this needs to be done according to the properties of your print and finishing process.
UCR removes amounts of CMY (which mix to make a neutral gray) especially in the three-quarter and dark near-neutral color areas and replaces them with Black. This allows reduces the total ink amount, which optimizes trapping behavior, e.g. in wet-over-wet print processes. UCR effects mainly the near neutral colors preserving the colorful appearance in the half and quarter tone and more chromatic color areas. It is mainly applied for conventional print processes like Offset or Gravure printing.
GCR replaces amount of CMY in all areas where the three color overprint. The Black channel becomes heavier and the CMY channels behave more as skeleton colors. For digital printing systems it can also help to avoid bronzing and metamerism effects, because CMY inks tend to cause these issues more than Black. Because of this, UCR is used in conventional as well as for digital print processes.
Answer to initial question: The UCR and GCR curves, as seen in ProfileMaker are not available in the same way in i1Profiler. i1Profiler is calling it ‘Black Generation Curve’ instead and allows you to modify this curve in 8 steps; minimum, light, light+, medium, medium+, heavy, heavy+ and maximum. The higher the curve value, the more Black is used to replace CMY.
i1Profiler also includes a completely new profiling engine, the UCR and GCR behaviour of ProfileMaker 5 and i1Profiler cannot be directly compared. However, here is a rough comparison of the settings:
- UCR in PM5 --> Black Curves minimum and light in i1Profiler
- GCR1 in PM5 --> Black Curve light+ in i1Profiler
- GCR2 in PM5 --> Black Curve medium in i1Profiler
- GCR3 in PM5 --> Black Curve medium+ in i1Profiler
- GCR4 in PM5 --> Black Curves heavy and heavy+ in i1Profiler
- MaxK in PM5 --> Black Curve maxium in i1Profiler
If you are unsure, what settings to use in i1Profiler, turn on the option "Use defaults". This specifies a Total Ink Amount of 400%, which does not necessarily mean, that the profile results in 400%, because the profiling engine determines based on the given measurement data, which value delivers the largest possible color space. Additionally, it specifies a Black Generation Curve of medium+, which is a very compatible setting for most print processes.
Please note, that it also depends on the properties of the measurement data (which does finally represent the print process behavior), how the Black Generation Curves interact with the given data in terms of smoothness, neutrality and total ink amount.
A good way to evaluate the resulting CMY and Black curves in an ICC profile is to check the Gray Balance Curves using ProfileEditor 5 or to use a test image, which includes C, M, Y, K and Kcmy tonal wedges (e.g. in 5% steps), then apply the created profile and judge the tonal distribution visually or numerically.