Preserving Greyscale Dot Gain in CMYK mode

InDesign doesn’t have a grayscale space—placed grayscale objects output on the document’s CMYK black plate with their output values unchanged. When Overprint Preview is turned on, the document CMYK profile handles the preview of placed grayscale objects—an embedded Gray profile will show in the Links panel but it is ignored. With Overprint Preview turned off grayscale objects soft proof as sGray (2.2 Gamma), which would be useful if you are designing for web or screen display and not print.

Photoshop does have a Gray space, and if you want the soft proof of gray values to match between Photoshop and InDesign you have to use a Black Ink profile that matches the InDesign document’s CMYK profile.

For example, if your InDesign document has US Sheetfed Coated as its CMYK assignment you would want to use Black Ink -US Sheetfed Coated as the assigned Photoshop grayscale profile. Photoshop’s Info panel Actual Color shows the gray values that will output to the plates, and the Gray profile adjusts the soft proof to show the affect of dotgain:

Black Ink-US Web Coated assumes less dot gain, so the same output values display as lighter values:

To use a Black Ink profile in Photoshop open Color Settings>Gray Working Space>Load Gray... and choose the desired CMYK profile. The Gray profile will be listed as the CMYK profile with a Black Ink - prefix:

If the printer will not provide a CMYK profile, but is expecting you to make CMYK conversions (PDF/X-1a) you are shooting in the dark for both CMYK and Gray color management.

Hi

Basically you need an accurate ICC CMYK profile from the printer. That way no discussion on dotgain will be needed. 

Many printers have adopted the sensible approach of standards based printing, that’s what ISO 12647 and GRACoL are all about. 

These guys seem rather seriously out of step with current working practices 

I hope this helps

if so, please "like" my reply

thanks

neil barstow, colourmanagement.net :: adobe forum volunteer

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Sounds like this printer is very low tech.  26% dot gain is high as well, and it's rare (Like I have never seen one) where a printer will have equal dot gains in all colors.  Also of note is it's the printers' responsibility to adjust their process to a standard.  So that begs the questions, What print standard do they use and What print process is this? (ie Offset Flexo, Gravure etc) 

So go through those questions and try to give us a better picture of what you're dealing with if you can.  

The reason for those questions is there are 2 ways now to get to your solution.  

One is to convert to CMYK with a standard profile that compensates for a "normal" amount of dot gain and lighten the files afterward using curves to go the rest of the way your printer needs.  I suggest this but I'd go so far as to say that your printer must, if they have been in business for very long received file that are at print standards and uses them.  They compensate with plate curves and life is good.  That would be the expectation of anyone supplying files to a printer.  

The other is doing a custom CMYK profile in PS where your responsibility is total for every little bit of how that conversion and print process will happen. I don't recommend this because so far at least the information received here doesn't tell us if you have any proofing capabilities.  Without proofing capabilities this is a bad road to take.