Problem: Bright Green Colors Change when Exporting to PDF

I have seen that, and I have seen discussions about it, but I have not found any simple silver bullet to make it work properly. It depends on colour spaces and colour profiles, but I have never figured out exactly how Apple thinks, and what features are shared between Apple and Adobe products.

I'm sure you will get more posts on the subject. If one of the coming posts helps you to fix the problem in a simple way, please, don't forget to acknowledge it, so we (or at least I) will learn what the trick was.

Thanks!

Have you made the color a cmyk color? OSX will convert it to a cmyk .pdf.

Bright Green is one of those difficult to reproduce colors in cmyk along with tans, strong blues and browns.

It will always look good in RGB because Green (G) is one of the 3 component colors in that color model. In cmyk it needs to be mixed from cyan and yellow neither of which are pure.

If you can give me the specs for the color, I can suggest a better approximation in cmyk.

If you use have Acrobat Distiller as part of Adobe Acrobat you can set up your own printer and create a .pdf workflow that retains .rgb color. The only problem will be that given the way Pages has been programmed there still will be a mix of .cmyk and .rgb in the output files with nothing really telling you what is what.

Peter

PeterBreis0807 wrote:
OSX will convert it to a cmyk .pdf.

I lost you already at the first line. I made a test inserting a shape, setting it to a green colour outside CMYK gamut. If I export or print to pdf, the created files reproduce the colour correctly in Adobe Reader. If I print to pdf-x, the colour is correct in Preview but not in Adobe Reader.

However, doing a preflight on the files, they all come back with RGB as colour space. Where do you see that anything is defined as cmyk?

#@$% if you aren't right Magnus,

Everything is being converted into rgb! Including cmyk objects.

How incredibly useful! NOT!

Has something changed, because in previous tests I did manage to get cmyk output?

btw In my tests the rgb green stayed true in appearance in Pages, Preview, Acrobat Pro, Acrobat Reader 9.01 and in Illustrator CS4. I printed to PDF-X, exported to Best .pdf and copy and pasted to Preview then saved as .pdf.

I am currently not near a PC to test under Windows.

Peter

As far as I remember from my last test series, all objects kept both colour space and colour profile.

You could easily create a pdf from Pages with a mix of rgb and cmyk.

That's why this problem always baffled me. Colourwise everything looked fine in the pdf, and yet there clearly were problems.

Magnus,

Well I did all my previous tests when I was still using OSX 10.5.5 or 10.5.6.

I am now using OSX 10.5.7.

I just have just done a thorough set of tests including going via Preview and forcing it onto the PDFX-3 quartz filter.

It has consistently converted everything to rgb with one exception where I think a background white bounding box was in cmyk and the object was rgb.

This is so weird!

Peter

PeterBreis0807 wrote:
Well I did all my previous tests when I was still using OSX 10.5.5 or 10.5.6.

Hmmmm... I do not remember when I last tested this, but it was definitely before 10.5.5. I'm on PC now, so I cannot redo it right now, unfortunately.

What kind of graphics did you test with? I think I tested with imported jpeg files modifed with Photoshop to different colour spaces and with correct colour profiles. That could be completely wrong though.

Peter Breis posted:

Have you made the color a cmyk color? OSX will convert it to a cmyk .pdf ... If you can give me the specs for the color, I can suggest a better approximation in cmyk

Converting to CMYK? You have no hope of suggesting a CMYK combination for the desired colour outside of a colour managed process. And if you do define colours in an ICC PRTR Printer colour space with data space CMYK, you have to embed that 1.5Mb profile into your PDF or the colourants will become colour blind device data.

Displays cannot image CMYK at all by definition, the system must either apply a colour blind channel conversion to RGB data space or assign a default ICC PRTR Printer profile with data space CMYK (: Generic CMYK Profile in OS X) so that colourants can be mapped to colours and the colours can be input to the Profile Connection Space for repurposing.

It is OK to criticise the ICC colour management model and it is OK to criticise corporate implementations of the model, but it makes no sense to criticise if there is no concept of what the ICC colour management model aims to achieve and how everyday endusers may work with the model instead of butting their heads blindly against it.

Sigh.

/hh

Just to let you know, the exact CMYK color scheme of the color I want is 49, 0, 85, 0, and the RGB scheme is 0, 206, 0.

These are device data, that is, these are colourant combinations as if you said 'A pint of this paint pot and a paint of that paint pot' without saying what colour the first paint pot and what colour the second pain pot is supposed to be.

If you send the same colourant combination to a score of devices, you will get a score of colours. The aim of the ICC colour management architecture is to keep the colour by constant by changing the colourants using ICC colour device characterisations.

You need a source ICC colour space, in Apple Pages this is implicitly Apple's Generic RGB Profile. This is your RGB window on the Profile Connection Space. You need a destination ICC colour space for your intended printing condition. You need a rendering intent for the printing transform, usually Perceptual for photographs and Saturation for flat colours. And you need a rendering intent for the proofing transform, either Relative Colourimetric if the printing paper and the proofing paper are colourimetrically close or Absolute Colourimetric if they are not close.

If you are trying for a colour match between two displays, and not between a display and a printer/paper target, then you need to get the two displays colour managed and you need the viewing conditions to be in line with the colour management configuration.

/hh

PeterBreis0807 wrote:
Well I did all my previous tests when I was still using OSX 10.5.5 or 10.5.6.

I am now using OSX 10.5.7.

I just have just done a thorough set of tests including going via Preview and forcing it onto the PDFX-3 quartz filter.

It has consistently converted everything to rgb with one exception where I think a background white bounding box was in cmyk and the object was rgb.

I did the same tests as last time, and came to the same conclusion as last time now in 10.5.7 with Pages 4.0.2.

1. Take a screen capture of anything.

2. Open the resulting png file in Photoshop.

3. Save as rgb.jpg.

4. Change colour space to cmyk in Photoshop.

5. Save as cmyk.jpg.

6. Drag both files from the Finder to a brand new Pages document.

7. Create three PDF files: print-save, print-save-as-pdf/x, export.

8. Open the PDF files in Adobe Acrobat Pro.

9. Run preflight on each of them.

All images in all three files kept their colour space and the colour profile that Photoshop gave them.

It is interesting that you get a completely different result. You always know what you are talking about... well, in much more than 95% of the cases anyhow. 🙂 So it is intriguing that you get image conversions somehow. Could you give a step by step description?

This is so weird!

Few truer words have been written in this forum.

Jacob Silvermetz wrote:
Just to let you know, the exact CMYK color scheme of the color I want is 49, 0, 85, 0, and the RGB scheme is 0, 206, 0.

The color it changes to in Adobe is CMYK: 59, 1, 90, 2 and RGB: 7, 177, 46. It's really significant.

Does that help in honing in on the problem? I noticed that the nearest "web safe color" is 66CC00. does that make a difference?

Try reading Henrik's post. What he writes is not always easy to understand, but it often has quite a lot of sense.

How do you measure the colours in Adobe Acrobat? (I assume you mean Adobe Acrobat, when you write Adobe.) And how do you measure the CMYK and RGB colours in Pages?

You can try the following, if you want to be confused:

1. Create a new shape with any colour.

2. In the inspector, double click on the colour fill to open the Color Palette.

3. Click on the second icon in the Color Palette toolbar (the sliders). It is probably set at "RGB sliders".

4. Write down the RGB values.

5. Click on the icon to the left of the drop down "RGB Sliders". You will get a list of RGB colour profiles.

6. Choose any of the colour profiles different from the current one.

The RGB values will (most likely) change. The colour of your shape will not.

This is why the colour profile is as important information defining a colour as just the RGB values.

As far as I remember from my last test series, all objects kept both colour space and colour profile. You could easily create a pdf from Pages with a mix of rgb and cmyk. That's why this problem always baffled me. Colourwise everything looked fine in the pdf, and yet there clearly were problems.

This is technically correct.

PDF 1.3 and higher provide object-oriented colour management. There is ICCBased for objects that reference embedded ICC profiles. There is Calibrated Colour for objects that reference embedded PostScript Color Space Arrays. There is device colour (device Gray, device RGB, device CMYK). There is spot 'colour' (in callouts because spots are a subclass of device colours). And so forth.

Suppose five photographers supply photographs to the same typographer who is preparing the printing surface. Each photographer, like Peter Breis, is under the impression that CMYK defines colour and each photographer supplies device CMYK to his or her whimsical concept of the target printing condition.

Suppose that the typographer believes the photographers to be technically competent, and consequently builds out a printing master where the ink limit, the black replacement, and the gray balance are different for each photograph on each page. Johan Leide who drove ICC implementation at IFRA in Darmstadt had something to say about this scenario.

Instead, place TIFF with embedded source ICC RGB colour space for the colour correction space, not for the capture space (scanner spaces are non-linear) and not for the correction space (monitor spaces are non-linear, too). An idealised ICC MNTR Monitor space is graybalanced and as it does not use LUT Lookup Tables it is small compared to an ICC PRTR Printer space.

Embed the destination profile as OutputIntent which converts source colour spaces into that one and only one destination colour space which will determine the colourants to be laid down, including the ink limit, the black replacement, and the gray balance. In other words, the printing press is a peripheral to the ICC PRTR Printer profile.

Embedding the destination profile as OutputIntent adds an intermediate colour space to the ColourWorld. However, whether only one object is colour managed (e.g. one photo in Aperture, LightRoom, ColorFlex or what have you) or complex object-oriented ColourWorlds are configured in pagination, the display profile is the place where one first sees the colour appearance rendered.

A good display, a good display profile, and good viewing conditions are important.

/hh

Henrik Holmegaard wrote:
And if you do define colours in an ICC PRTR Printer colour space with data space CMYK, you have to embed that 1.5Mb profile into your PDF or the colourants will become colour blind device data.

Sorry, but you lost me there.

I did some tests, which taught me some new things, which confirm what you say, but I still do not understand it.

If one creates a pdf from Pages with just a default shape and a simple colour profile, the pdf is really small, like 4k. However, if the fill colour is defined using one of the biger colour profiles I can find in /Library/Application Support/Adobe/Color/Profiles/Recommended, like USWebUncoated, then the PDF file increases in size. In this case the PDF popped up to 376k. So yes, the icc profile seems to be physically embedded in the PDF.

However, what is the data that makes one colour profile bigger than another in an order of magnitude? What is the information one profile needs to convey that another one does not?

Magnus,

I created 2 shapes in Pages and applied known RGB colors to the round shape and cmyk colors to the Square shape, using the color sliders in the Color Picker. The teutonic method in my madness. 🙂

I would assume the best test is to only use objects originating in Pages.

All .pdfs were tested in Illustrator CS4 leaving the original ICC profile on opening.

Both shapes consistently convert to rgb except that one instance of the +background white+ was cmyk, with the overlying shape converted to rgb.

Peter