Working with a new printer and need help!

[tomh70401108]

Hello! I'm a long-time Adobe user, but recently I've needed to become more familiar with print production, which is a bit of a new area for me.

My company makes comics and recently started working with a new printer. They have a few demands of us when supplying them with print-ready files:

- They've asked us to use the colour profile PDF/X-1a:2001 when exporting print-ready pdfs in InDesign.
- They've asked us to limit our TAC (the total ink density) to 240%.

To achieve this, they've asked us to alter every single image in our print-ready pdfs using the following method (their words):

"- Open the image into Photoshop.

- Create a non-destructive Curves layer with a mask originating from the Black channel, so as to not adjust the brown.

- Remove color from the C, M, & Y channels individually, and bumped up the Black channel.

- This allows us to keep the darkness of the black while complying with the TAC.

- The same tactic can be used for other colors (dark reds, greens, etc) by removing the non-critical channel percentages, and bumping up the dominant color channel.

- This has to be done on an image-by-image basis.

- The use of profiles within the PDF is not honored by LS printers, so directly adjusting the images is required."

I really want to avoid doing this on an image-by-image basis, as there are over 200 books we want to print with them, containing many images. My questions are:

- Is it reasonable for them to specify a colour profile for us to use, and then demand we adjust the TAC manually in all images?
- Is there a way to fix this issue when exporting the pdf in InDesign or with the Print Production tool in Adobe Acrobat Pro?

Basically, is there a way to meet their request (colour profile and TAC) without going through Photoshop? And for a comic, shouldn't we be able to exceed 240%? Any help massively appreciated!

[Mike Witherell]

They seem to be stuck in the mid 1990s and supplying you with outdated advice.

[tomh70401108]

That makes sense because I've never encountered these kinds of limitations before.

[Mike Witherell]

Have you considered questioning their more-experienced person to see if that is actually necessary?

[tomh70401108]

It seems their highest-level person is telling me this stuff. Hoping someone here will give me the ammo I need to call nonsense on them and stop my company charging ahead with using these guys! Any insight is most appreciated.

[rob day]

- They've asked us to use the colour profile PDF/X-1a:2001 when exporting print-ready pdfs in InDesign.

- They've asked us to limit our TAC (the total ink density) to 240%.

Are you printing on newsprint? Usually to get a TAC of less than 300% you have to convert to an uncoated CMYK profile, and to get less than 240% it would probably need to be a newsprint profile. PDF/X-1a is a PDF standard, not a color profile. It forces all color to CMYK, and you can use any CMYK profile as the document or destination profile.

The fact that the printer is asking you to manipulate the CMYK output values via a curve layer tells me that they don’t actually understand how color conversions or color management works. The total ink is limited on the conversion from RGB to CMYK—TAC is built into the CMYK profile used during the conversion. If the correct profiles are used there would never be a reason to adjust the CMYK values.

[tomh70401108]

Thank you, that's helpful information!

[rob day · Accepted solution]

Any insight is most appreciated.

This shows the affect of the document CMYK profile on total ink. Most importantly, it is the conversion from RGB to CMYK that controls total ink. If you made the conversion to a profile like default US SWOP Coated over in Photoshop, the total ink could be as high as 300% and assigning a different profile in either PS or ID would not change that.

So here I‘ve placed an RGB file in a document with Coated GRACol as the CMYK assignment:

Separation Preview‘s Ink Limit shows me that GRACol’s ink limit exceeds 300%

If I change the document‘s CMYK profile to a newsprint profile, and set the Ink Limit to 240% there are no violations. Separation Preview gives me the conversion output numbers for an export to PDF/X-1a where the destination is set to Document CMYK.

Keep in mind the CMYK profile handles more than total ink, it also is used for the color soft proof.

[tomh70401108]

Thank you for that, very helpful! Much appreciated and I think that's all I'll need.

[Stephen_A_Marsh]

Keep in mind that Rob was using newsprint as an example of a commonly found low total ink limit. If the printing method is NOT newsprint, your image quality would suffer if you converted the entire image into a newsprint CMYK just to reduce the total ink limit.

The method that your service provider recommends is a poor method of reducing total ink when compared to using ICC profiles. ICC profile based methods or even better, DeviceLink ICC profile based methods will limit the darkest areas without adversely affecting shadow transitional and three quarter tones and below.

Your service provider has recommended a PDF export profile, but not a target ICC colour profile. What colour profile are you converting into?

There has been so much confusion caused by some print on demand publishers, who ask for a 240% limit but advise to use an ICC profile that uses 300% total ink and then in different specifications say that RGB is also OK and that they will convert.

https://indesignsecrets.com/force-color-images-cmyk-240-ink-limit.php  (check the comments)

What I would advise is posting a download link to an original sample image or three, and the conversion that you are making using their advice. I’m pretty sure that one can do better.

[Stephen_A_Marsh]

Basically, is there a way to meet their request (colour profile and TAC) without going through Photoshop? And for a comic, shouldn't we be able to exceed 240%? Any help massively appreciated!

Yes there is.

If you have RGB images in your layout, convert on PDF export to a CMYK profile for the output condition that delivers an appropriate 240% total ink value (perhaps easier said than done).

I would suggest using an appropriate Device Link ICC Profile and Enfocus PitStop Pro to convert all CMYK images from the known source condition to the known output condition.

Otherwise I would setup a batch in Photoshop to process the images using an action designed to deliver the appropriate ink limit without overly impacting the appearance of the image, update the links and create the PDF.