How do ICC profiles work?

[Notarealsignguy]

I know this is a dumb question but will ask anyways. Are ICC profiles universal or RIP specific? Could an i1 be used in Flexi and transfer that over to an older version of Flexi or even use in Onyx or any other RIP? Can you create profiles independent of your RIP? I'm not real sure how this all works honestly.

 

[Boudica]

I wish I could help, but I can't so instead I'll offer this:

 

[Pauly]

The simplest way i can explain it:

the ICC profile is the colour look up table for your RIP to understand which CMYK values your printer needs to hit the colours in the artwork.
The media profile is your whole printer & media calibration. This includes ink restrictions, ink limits, print speeds and other variables + the icc profile at the end.

It's basically a calibration for your printer + media.

Can you transfer from Flexi to an older version? Probably not. (im not sure, never used it) you can try exporting and importing it but most things dont go backwards.
Can you use it in another RIP: nope.

You would need to create a new one for onyx, or any other software. when created they should in theory, match the old profile from the old RIP. but doesn't always work that way as there may be different variables. but most of the time it'll be close enough.

 

[ColorCrest]

Can you create profiles independent of your RIP

Yes, X-Rite and others do just that. The RIP just prints their swatches. ICC profiles are then generated using their software, and often, their hardware.

ICC profiles are transferable but only truly accurate if machine “B” already matches machine “A” so far as calibration. (Machine A being the original ICC swatch print source.) That’s the concept of “canned” profiles from the manufacturers. Hopeful is a user’s machine prints today as the factory machine did 3 years ago. Yes, hopeful at best.

EDITED TO ADD: "but only truly accurate if machine “B” already matches machine “A” so far as calibration" and color gamut.

 

[netsol]

we have an I1 at all 3 desks, so whoever is designing can build a profile for new materials, BUT, i would be embarassed to tell you truthfully how often we actually do that... ( i had good intentions)

 

[ColorCrest]

the ICC profile is the colour look up table for your RIP to understand which CMYK values your printer needs to hit the colours in the artwork.

The ICC profile is the "fingerprint" of the printer colors using L*a*b* values at the time the ICC swatches were printed. Many of the values are likely very different from target values. The CCM (color management module) implements the transforms between the two, again using L*a*b* values.

EDIT: The above has been corrected to read "color management module" and not engine as originally posted. The CMM is a component of the overall color management systems
supplied by both Microsoft and Apple for their operating systems and also from Adobe for their Adobe Color Engine (ACE).

 

[Notarealsignguy]

The ICC profile is the "fingerprint" of the printer colors using L*a*b* values at the time the ICC swatches were printed. Many of the values are likely very different from target values. The CCM (color management engine) implements the transforms between the two, again using L*a*b* values.

I'm sort of following this point. So it essentially measures lab values from a control point, then your printer output, runs through software which adjusts the ICC to match the control, reprint and check again? Or do you have to tweak parameters over and over until it tells you the match? Is it either right or wrong or is there a delta given for the match?

 

[ColorCrest]

I'm sort of following this point. So it essentially measures lab values from a control point, then your printer output, runs through software which adjusts the ICC to match the control, reprint and check again? Or do you have to tweak parameters over and over until it tells you the match? Is it either right or wrong or is there a delta given for the match?

Either a third party such as X-Rite or a RIP (if it's capable) provide known swatch color target values to be printed. After reading the swatches using a spectrophotometer, the printed values are then known and the ICC profile is created. The CMM then compares the new values against the known values to perform an actual translation when called upon by design and printing applications, and yes, delta values are the difference. There are always many differences both great and others not so much.

 

[ColorCrest]

reprint and check again? Or do you have to tweak parameters over and over until it tells you the match?

Surely, a verification print is in order. However, if all was properly done before the actual swatch printing and readings, there isn't any tweaking to be done so far as the ICC. ICC editing software itself is no longer available, AFAIK, and results would usually compromise more colors than were fixed anyway. On the other hand, a machine can be wildly out of sorts color-wise but the color management system can correct color to a shocking degree. Think a heavy cyan nozzle deflection overspray on the trailing X edge of prints yet the entire image is practically perfect other than that edge.

If for some reason, such as deep colors appear without detail as compared to a control image from six months earlier, the exact place to "tweak" the setup might be difficult to determine. It's not going to be the existing ICC itself. New readings might need to be made and possibly new swatch prints. In any case, an entirely new ICC is created and hopefully it's better. As a guide, it's useful to keep an evaluation print from very early on (preferably when the machine was newly delivered) printed with both ICC profiles on, and off. Doing so enables easier determination of the machine's more basic state of printing colors as well as mechanical qualities vs the ICC area of just printing colors accurately.

 

[Notarealsignguy]

Either a third party such as X-Rite or a RIP (if it's capable) provide known swatch color target values to be printed. After reading the swatches using a spectrophotometer, the printed values are then known and the ICC profile is created. The CMM then compares the new values against the known values to perform an actual translation when called upon by design and printing applications, and yes, delta values are the difference. There are always many differences both great and others not so much.

Where does ink density come into play and how is that controlled in relation to color shifting?

 

[Notarealsignguy]

Also to clarify the transferability of a profile depends on where it was created i.e. flexi vs x-rite?

 

[ColorCrest]

Where does ink density come into play and how is that controlled in relation to color shifting?

Ink density is the first step of the color setup process. From a basic starting point after telling the RIP what type media is being setup, four colors (say CMYK in this case) are printed in steps of percentages. Those steps are read for their density so then RIP can then adjust them toward the target known from the initial media it was told as the setup. It ends up as 4 curves from light to dark; 0 to 100%. This is also where max color gamut results, ideally without over inking which can actually reduce gamut and waste ink.

Color shifting from this area would only occur if erroneous settings were used or mechanics such as head trouble were to affect a color change.

 

[ColorCrest]

Also to clarify the transferability of a profile depends on where it was created i.e. flexi vs x-rite?

First, be sure to understand the difference in terminology between an overall machine "profile" vs an ICC profile. ICC profiles can be transferable as they are just a component of a machine / ink / media setup. Another name for an overall machine profile is "environment," a term used by some RIPs. Also, Rips such as Onyx combines the ICC within its special OML file package. I don't recall Flexi's package, if any.

In any case, an ICC profile by itself is transferable regardless. It's accuracy and usefulness is another discussion. A printer would need to produce a print which matched the printer from where the ICC profile was made. Again, just as canned profiles are supposed to be used.

 

[FrankW]

The first step for creating a media profile/environment etc (RIP-manufacturers name that differently) is named „calibration“. This means that you define the optimal printer settings, you limit the maximum amount of ink the media can work with, and doing linearization (creating a linear increase of print density). This is something which is not standardized, every RIP-manufacurer saves this in proprietary file formats.

After that, you do „profiling“, which means creating an ICC-profile, for maximum color accuracy, on base of your calibration. This is a standard file, but sometimes embedded in a “media profile“ that it cant be separated. Unfortunately, some manufacturers have files with the suffix .icc, but save their calibration data into it too (for example Flexi or Mimaki Rasterlink). Others have the ICC-profiles separated (but linked with calibration data), but because of the profile is based on the calibration, the benefit of using that profiles with other softwares is limited.

There are separate ICC-profiling softwares, for example the i1 Profiler from X-Rite, who are able to create ICC-profiles for nearly all common RIP-softwares. They only need to be able to create CMYK-profiles (is an option with i1 profiler, RGB printer profiles are for desktop printers driven by system drivers only). In this case you do the „calibration“ in your RIP, print a measuring swatch generated by that third party softwares with your created calibration out of your RIP, read them in i1 Profiler, let i1 profiler create the ICC-profile, and import that ICC to your RIPs media calibration. In Flexi, when reaching the last step of the calibration, you can do that with the button „Third Party Profiles“.

The easiest way is to have all in one workflow, in your RIP-software. Doing profiling with separate softwares could lead to problems, for example if printing the third party measurement swatches under wrong conditions.