Colour Management Settings

neilcollins_wales
Newbie
Posts: 2
Joined: Tue May 09, 2017 5:04 pm

Colour Management Settings

Postby neilcollins_wales » Tue May 09, 2017 5:23 pm

Hi guys,

I need a bit of help on the general color management settings withing Pitstop 13.

I am having trouble with converting PDFs which contain spot colours to 4 colour process. I am getting varying results between PC / Macs / Different versions of Pitstop etc. I'm trying to get some general settings to follow for general spot conversion to 4 colour across the various machines. This will be difficult to do as mentioned I have different machines and software. I'm trying to get a good base to start from using a Mac with the latest Acrobat DC and Pitstop 13.

1) Is it better to use Pitstop to handle 4 colour conversion or Acrobat ?
2) What CMM Engine should I use ? (System CMM / Little CMM etc)
3) How do the Source / Target profiles work ? What should I aim for as a general setting ? My old settings were US Web (Swop) v2

We run a small print shop where the PDFs supplied are generally awful bits of artwork knocked up in five minutes where colour isn't critical. However we do get the odd item that causes a problem when supplied with spot colours which we convert. I output to plate via an Apogee prepress client, and tend to avoid the colour management on that.

Any help as a base starting point would be gratefully received. For years we have just relied on the standard installation settings, but over time various users have tinkered with the settings on each machine and I would now like to try and get some consistency if possible.

Thanks for reading !

Neil

bens
Member
Posts: 128
Joined: Thu Mar 03, 2011 10:13 am

Re: Colour Management Settings

Postby bens » Thu May 11, 2017 11:09 am

Hi Neil,

Colour management is a broad and interesting topic - much too broad to explain it all in a few sentences. As a general introduction I heartily recommend the article http://www.colorwiki.com/wiki/The_Color_of_Toast on the colorwiki.

Specifically for your questions I can give some recommendations, but in the end you'll probably just have to experiment to find the perfect (or, as the case may be, the "good enough") settings for your workflow.

The most important thing to get consistent results in different applications is to use the same settings in each. It doesn't really matter whether you use Acrobat or PitStop, as long as the same settings (ICC profiles, Black Point Compensation, rendering intent, ...). Note that PitStop has more settings than Acrobat.

The CMM Engine also doesn't matter much - apart from some edge cases the different engines will give results close enough that the human eye sees no difference. For consistency I would recommend Little CMS since it is available on all systems (but, sadly, not in Acrobat).

Source ICC profiles should match the colour environment that was used to create the artwork. Given your statement about where the artwork comes from, I'm guessing you don't have any idea about the colour settings at the source - let alone any control over it. In such a case I would recommend using a very generic profile; for example sRGB or Adobe RGB for RGB and Coated FOGRA39 for CMYK.

The output ICC profiles should match your output device. That means you should use calibration software to create an ICC profile specifically for your output device. If that feels like overkill (it may very well be in your case), I suggest you use the Acrobat Colour Management preferences to decide which profile to use. In the Acrobat preferences panel, when you switch between different CMYK profiles, you'll see a short description of that profile's intention. Pick one that sounds right to you, and apply it consistently on all systems and in all applications. The most important part is probably to choose between Coated or Uncoated.

Note that you can tell PitStop Pro to use the CMM settings from Acrobat (for those settings which are available in both products).

Ben

neilcollins_wales
Newbie
Posts: 2
Joined: Tue May 09, 2017 5:04 pm

Re: Colour Management Settings

Postby neilcollins_wales » Thu May 11, 2017 12:38 pm

Thanks for your detailed reply. Most appreciated.

In the last 24 hours I have tinkered and read up on many of the issues and have settled on some generic profiles.

The issue really stems from comparing colour conversion from an older version of Pitstop to the most recent version.
Specifically - converting pantone 287C to process. A large customer of ours supplied many items setup as 287C and wanted them converted (without supplying the specific splits that they wanted). Using pitstop, the results I got were:

C 100 M 84 Y 27 K 9 (On slightly different settings I was getting as much as 18 black)

On press, this blue was way too dark. Looking back on previous conversions we did - using an older version of Pitstop with similar settings I was getting:

C 98 M 80 Y 3 K 1 (Far lighter and we got better printing results - which the customer was happy with)
Whether these settings are accurate or not, there is quite a variation in the amount of black used.

How come more recent versions of Pitstop convert colours so differently ?

I now have to manually change the blue as the customer was happy with the older split.

How does Pitstop generate it's splits ? Has it been tweaked or changed with the newer versions ?

I'm finding it difficult to explain to the MD that a PC with an older version of Pitstop gives different splits to that of a new MAC with the latest Pitstop.
He's asking why it has changed and does this mean the older jobs we produced are now wrong in terms of the colour splits ? How do we get consistency without paying for even more Pitstop licences and buying more copies of the latest Acrobat etc - having identical machine setups.

Quite frustrating !

bens
Member
Posts: 128
Joined: Thu Mar 03, 2011 10:13 am

Re: Colour Management Settings

Postby bens » Thu May 11, 2017 3:32 pm

Spot colours in PDF contain an "alternate" which is usually CMYK or Lab. This is what PitStop uses to calculate the conversion to CMYK, and (barring some bugfixes) this has not changed significantly in the last few years.

I suggest you double and triple check your settings to make sure they're exactly the same in each version. And be sure to use the exact same file to check: just because a spot colour is called "PANTONE 287 C" doesn't mean it's the same one as in a different PDF.

If you still can't find an explanation I think you should contact Enfocus support at [url]https://www.enfocus.com/en/supportportal[url] and provide them with a sample file, your colour management settings, and the versions of the applications you're using. They should be able to help you out.

Ben


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