Grayscale document exported for printing still contains CYMK colours

[Thijs Amersfoort]

I've used Affinity publisher to design a book that I want to send to be professionally printed. The colour space of the document is in grayscale, I made the text 0 gray on the grayscale, exported it to pdf explicitly in grayscale (D50), and still the text in the pdf seems to be build up in CYMK colours. How is this possible? How can I export to a purely black and white pdf, ready to be printed in black and white, instead of in colour?

[Hangman]

Hi @Thijs Amersfoord and welcome to the forums,

Could you upload your pdf or even just one page from your exported pdf file so we can take a look as your pdf shouldn't be exhibiting any CMYK colour.

 

[walt.farrell]

A Grayscale document is a form of RGB document, I think.

For your purposes, I would use a CMYK document, and the "color" you want is 0/0/0/100.

If you have Placed images, you can use the K100 button in the Context Toolbar to make them "grayscale".

[Old Bruce]

59 minutes ago, walt.farrell said:

A Grayscale document is a form of RGB document, I think.

I suspect that the Grey Colour Palette also uses RGB values for the Greys.

[walt.farrell]

30 minutes ago, Old Bruce said:

I suspect that the Grey Colour Palette also uses RGB values for the Greys.

Yes, it does.

[Hangman]

1 hour ago, walt.farrell said:

A Grayscale document is a form of RGB document, I think.

Grayscale differs from RGB Greyscale in that Greyscale only has one channel, RGB Greyscale would be a three channel file creating varying grey's using equal amounts of RGB, e.g. neutral grey R128, G128, B128.

25 minutes ago, Old Bruce said:

I suspect that the Grey Colour Palette also uses RGB values for the Greys.

That wouldn't result in CMYK values in the exported pdf unless exporting as PDF/X-1a which I suspect is what is happening here... i.e., the Document setup clearly uses Grey/8 and Greyscale D50 and based on the comment saying "I made the text 0 gray on the grayscale" that suggests the text is using greyscale values but regardless, if the file were exported using PDF/X-1a with Colour Space set to As Document then that would result in a CMYK file...

[Hangman]

38 minutes ago, Old Bruce said:

I suspect that the Grey Colour Palette also uses RGB values for the Greys.

It does, but that's only relevant if your document uses an RGB colour space, based on the description given in the original post that's not the case... If using a Greyscale colour space then exporting to pdf using e.g., the Press Ready PDF preset would result in a Black Plate only export, no CMY...

[Old Bruce]

I made a Greyscale document and used the Greys Colour Palette from the Swatches panel. Here is the Black from the Greyscale document. The RGB values are 0 0 0.

[thomaso]

3 hours ago, Thijs Amersfoord said:

exported it to pdf explicitly in grayscale (D50), and still the text in the pdf seems to be build up in CYMK colours. How is this possible?

As far I know the "D50" profile is not really grayscale only. Also note that the PDF viewing app must be able to display the PDF with its profiles.

Here @lacerto demonstrates in a video this often discussed Affinity grayscale issue and one way to avoid it on export:

 

[Hangman]

40 minutes ago, Old Bruce said:

I made a Greyscale document and used the Greys Colour Palette from the Swatches panel. Here is the Black from the Greyscale document. The RGB values are 0 0 0.

Hi @Old Bruce, I'm sure I've missed the point but I'm not quite sure what you are demonstrating here... Uncheck the Lock Colourspace padlock in the Colour Panel and then click your rectangle/s and you will see that the colour values used in the Greys swatches panel use RGB values...

 

[Hangman]

45 minutes ago, thomaso said:

As far I know the "D50" profile is not really grayscale only.

D50 and D65 are display white point values...

To quote...

"D50 and D65 are the most common temperatures. D50 is a warmer white used for commercial CMYK printing (IC laser printing) and imitates the yellow-cast of paper. D65 is cooler in color and is best for inkjet printers (IC inkjet printing). D65 is also a good setting for photography and digital output."

and...

"D50 is a consistent and standardized light source of critical importance for professionals in the graphic arts and printing industries. The reason? Different lighting conditions can create different visual perceptions of the same object, leading to serious control issues when performing basic colour-based tasks such as proof viewing and color matching.

In order to minimize such variations, the International Standards Organization established a standard called ISO 3664. The standard dictates that when viewing prints, a light source that replicates the D50 light source should be used."

[Thijs Amersfoort]

On 5/1/2023 at 4:24 PM, Hangman said:

Hi @Thijs Amersfoord and welcome to the forums,

Could you upload your pdf or even just one page from your exported pdf file so we can take a look as your pdf shouldn't be exhibiting any CMYK colour.

 

Of course, see attached

NT14x19_flexcover.pdf

[Thijs Amersfoort]

These are the export setting I use. At first, I just used "as document" for the colour space, but after first complaints from the printing shop, I set it to explicitly export to gray and convert colour spaces of images.

[Hangman]

Hi @Thijs Amersfoort,

The Issue here is that the Registration Marks on your exported PDF use Registration Black, i.e., C100, M100, Y100, K100. You should check with your printing company as it's highly likely that they will want the artwork provided without any printers marks which would resolve the issue.

This does raise the question as to whether it is possible to 'convert' printers marks to K100 for greyscale document export to PDF within Publisher. As far as I know that is not possible but maybe other's can confirm.

I know they can be converted in Acrobat Pro by doing the following:

• Choose Preflight
• Click the Single Fixups button
• In the Convert Colors Fixups, choose Convert Registration Colour to CMYK Black Only
• Click Analyze and Fix. You'll be prompted to Save the PDF

[lacerto]

23 minutes ago, Hangman said:

This does raise the question as to whether it is possible to 'convert' printers marks to K100 for greyscale document export to PDF within Publisher. As far as I know that is not possible but maybe other's can confirm.

i do not think that it is possible in InDesign, either (not at least in CS6): even when forcing conversion of color space to pure gray, the print marks (crop, bleed, registration) are always tagged with "Registration color" (similarly as when exporting from Publisher). Grayscale bar is also always registration color (10% black is C10M10Y10K10). Only the color bar is in DeviceCMYK. So I guess you are right: if registration color is problematic, it is likely that print marks are not wanted.

EDIT: Being tagged as "Registration Color" would of course mean that when separated and K plate only is output, the print marks would print correctly as K-only, together with "DeviceGray" art. So they should not be problematic in any case (expect for a brain-dead preflight routine).