CMYK Printer Profiling
Detailed Instructions
Please note we can also make CMYK+N profiles (i.e. profiles of multi-colour processes, usually 6 or 8 colours). This is definitely more complex and requries a custom set of target files for best results. Please contact us if you are interested in this service. CMYK+N profiles are usually charged at $50 for target generation and $150 for the profile itself.
CMYK printer profiling is considerably more complex than RGB printer profiling, because typically an RGB printer driver hides all the complexity of ink limits and so on. Also, a good CMYK profile must sample a far greater number of patches than an RGB profile to produce high quality results.
There are two basic approaches to running a printing device:
- Calibrating to a known standard, e.g SWOP, or Euroscale coated etc.
- A full custom CMYK profile approch.
Calibrating to a known standard
- Generally the most appropriate with large offset presses
- Pick a common printing standard (eg SWOP), and calibrate your printer to this standard. This approach works if the press/printer itself offers colour controls (ie, take measurements by a spectrophotometer and or densitometer, and input these values directly into a control panel on the press). If so, then this is a non-profile approach and requires investment in a spectrophotometer, and tweaking of controls on the press itself during the print run (this approach is usually an option for old school offset presses, not modern laser print on demand type jobs).
Custom CMYK Profiles
- Generally the most appropriate process for inkjets running with a full CMYK RIP instead of a driver, dye sublimation printers, and laser based Print on Demand (POD) devices.
- Create custom profiles describing your printer's behaviour with specific media under ideal conditions. This offers the ultimate in quality and control and works very well indeed in general. However, if your printer's output varies considerably during a printing run (as presses and toner based machines sometimes do, but ink based printers generally don't), for the very best results you may still have to re-linearise (or even re-calibrate) to the profile on a regular basis, therefore requiring you to own your own spectro.
- N.B many laser based devices actually profile better when treated as RGB devices, so if you have a laser printer and you're wanting to profile it, best to ask us first about this.
Approach 2 Instructions - Custom CMYK profiles
Getting a good CMYK output profile rests heavily on producing a good set of target print outs on the stock in question. Target prints are prints containing color patches - the target we use has over 1500 colour patches. If you can put your printer into a consistent, repeatable state that produces good colour patches on a particular stock, we can profile it to a level of superb quality and accuracy. The profile can even be built with specific goals in mind - such as highest quality possible, or cheapest way to run the press (uses more black ink as this is cheaper), or some combination of these two goals.
The first step is to download the target files by following this link.
Then follow these instructions to produce a high quality set of targets:
- Turn off colour management in your RIP. This is (hopefully) just a case of ticking a 'No Colour Management' box, or 'Same as source' as the input and output profiles in the RIP. If this can't be done, best approach is to set the same input profile as output profile. This should set the RIP into a straight pass through mode where the target files will be sent unaltered to the printer.
(Later, when using the profile, the ideal is to set it up as 'Use document profile' for the input profile and your new custom profile for the output profile)
- Ink limits - Next we need to try and create the best possible targets to we can achieve the best profile. The idea here is to stop the printer laying down too much ink for the paper stock in question.
Print out a CMYK linearisation target (if your RIP did not come with one of these, you can download one here) to do this, and tweak your ink limits until you are at the point of most distinguishable patches in each of C, M, Y and K, making sure you still achieve the maximum saturation you are looking for.
Pay particular attention to black - the low low values should be 'tonal', not a muddy black.
Check the pure patches of cyan, magenta and yellow for purity (especially yellow). If there are dots through the so called pure colours, too much black is going down - re-do your ink limit test with less black
These ink limits must be recorded, and used when printing the profiling targets, and with the profile itself once you have it.
- (If your RIP/printer does not offer linearisation, then skip this step).
Now linearise the printer if possible. If this is possible - print the printer/RIPS own linearisation target and read this back into the printer (or send them to us for reading in here with our spectrophotometer).
Linearisation should also be re-performed when actually using the profile if it is available.
- Now print the targets using the settings you have determined.
Check the pure patches of cyan, magenta and yellow for purity (especially yellow). If there are dots through the so called pure colours, too much black is going down - re-do your ink limit test with less black (i.e. go back to step 2)
- Send your target to us using these contact details, with payment of $150 for each profile. Please send us details of your printer, the stock used, and settings used, so we can give your profile a sensible name. By default, we will build a profile that uses the minimum of black ink in grey component replacement, for the best possible colour photographic output. If you have special needs, such as wanting to run your printer the cheapest way possible, please indicate this with your order, or give us a ring to discuss.
Please include your full contact details with your order, including your email address, so we can get the profile back to you as quickly as possible.
- When your profile is returned to you, follow these instructions to use it properly. Remember the profile is a description of your printer's behaviour as you've set it up (ink limits etc) and is only valid for those exact conditions, so you must use the same settings when using the profile as you used when printing the target files. When using this stock, simply apply the profile to all files that go through your RIP and you should get superbly accurate colour (generally you just choose 'input profile: use document profile' and 'output profile: IS_Custom_Profile_goes_here' in the RIP) (and don't forget to relinearise using your ink limits if that is an option, each time you use this stock and profile).