Gray stays 4c after transformation

Hi everyone, thanks for the quick answers!

I'm working with Mac OS Monterey 12.0.1. and Photoshop version 23.1.1.
What I was trying to do is transforming a "grayscale" vector Logo into transparent TIFF. 
When I switched the mode to actual grayscale (knowing that there are multiple ways to do so) the "info" pannel keeps showing cmyk values for the gray elements, when in Illustrator it was 40% black only. 
The final purpose is indeed offset printing.
Anyways, in the meantime i figured out, that the logo indeed lies on the black channel only. 
So maybe checking the color in the info box is just not the way to go?

To help you, we need step by step of what you are actually doing, insert screenshots too please.

neil barstow, colourmanagement net :: adobe forum volunteer
google me "neil barstow colourmanagement" for lots of free articles on colour management

What is the intended use for the image? Screen? Inkjet print? Offset print?

It's simple enough to convert to grayscale, that's just Edit > Convert to Profile > <grayscale profile>. But you need to know which grayscale profile to use! That's the tricky part. The Photoshop default grayscale profile (dot gain) is useless for any practical purpose.

Grayscale profiles have very different tone curves, and grayscale is subject to standard color management to correctly remap from one tone curve to another, and thus represent the file correctly. The problem is that almost no other applications aside from Photoshop support grayscale color management. Only Photoshop will treat these files correctly! The net result is that grayscale is highly unpredictable for use anywhere else.

For this reason, I usually advise against grayscale, unless you really know what you're doing. Monochrome RGB, with an embedded profile, is much safer.

The primary use for grayscale is offset print, to print on the black plate only. In that case you need to use the K component in whatever CMYK profile is appropriate for the actual process. Go to the gray working space rolldown in color settings, and click "load gray". From there, navigate to the correct CMYK profile. It will look like this:

With this loaded, it acts as a standard profile and you can convert to it in Edit > Convert to Profile.

For screen, Gray Gamma 2.2 is basically workable in most scenarios. It should mostly work for inkjet too, but no guarantees.

If you convert an image to grayscale it is grayscale. 

And therefore it cannot be 4C anymore. 

What are you doing with the image downstream? 

Where do the 4C grays manifest? In an exported pdf, in a layout application, …? 

Hi Johannes, 

Thanks for reaching out! We are sorry for the trouble with Photoshop. We are here to help!  

Could you please share the exact version of Photoshop along with the operating system on your computer? What is format of image that you are working with? Do you notice the change after you have exported the image from Photoshop? Does this happen with all of your documents or any specific document? 

If you are working with JPEG files (input or output) you will notice this change because it is one of the drawbacks when working with lossy compression. To avoid this, you can try using TIFF file format to save the documents. 

Please let us know if this helps! 

Regards, 

Sameer K.