image editing in RGB and manual separations to CMYK for press

Forum|Forum|6 months ago
September 12, 2025
2 replies
632 views

We're asking if the following workflow and division of labor is advisable, as it's our most readily available option: Can we execute all needed image aesthetics editing in RGB (mostly B&W architectural images) under our careful eye with our retoucher first, then send the image files to a color corrections color space conversion expert (RGB to CMYK, manual conversions/separations) to manually convert and translate that work accurately to CMYK for high-end offset printing? This is as opposed to having one vendor do it all. We'd place the manual color space convertor's work back into our ID doc and export to pdf using the printer's Fogra 51 profile.

Is this division of labor between two parties (a retoucher, and then a color correctionist/separator) before printing not advisable? Ask any clarifying questions.

rob day

Community Expert

We'd place the manual color space convertor's work back into our ID doc

Also, in case you are not aware, you can get the expected CMYK conversion for profiled RGB colors without actually committing to the conversion. Here I have Proof Colors turned on with my Proof Setup set to Coated FOGRA39. With my Info panel’s eyedroppers set to Proof Color I can get the expected CMYK values for a conversion to FOGRA39 without committing to the conversion:

rob day

Community Expert

Can we execute all needed image optimizations in RGB (mostly B&W architectural images)

In almost all cases RGB B&W images will convert to CMYK using all 4 plates. If handled correctly that can get you more dynamic range on press, but you run the risk of color casts. For color work, color correcting in a large RGB space (ie, AdobeRGB, ProPhoto RGB, etc) with View>Proof Colors turned on is the preferred workflow.

There is no guarantee the color will print accurately—how you handle your display matters. All color in the Adobe print apps is converted into your system’s monitor profile for display—profiled RGB to Lab to the monitor RGB profile, or profiled CMYK to Lab to monitor RGB profile. If the system’s monitor profile does not accurately represent your monitor’s properties (gamma, white point etc) your color correction preview will be less accurate. Typically hardware calibrators are used to generate the most accurate monitor profiles.

TypothalamusAuthor

Known Participant

Rob, thanks for confirming the workflow and highlighting the 4-plate conversion complexity for BW images. For our BW image enhacements in RGB, the photo editor, who doesn't work in print, is focused on tonal editing—highlights, shadows, midtone gradations, sharpness, and texture preservation rather than color correction.

The division of jobs (BW photo editor in RGB → expert CMYK conversion) seems to make sense since managing 4-plate CMYK conversion for 240 images requires print-specific expertise our RGB photo editor doesn't have. This reinforces that manual conversion by a 2nd specialist after him is needed, as opposed to 1-click ID auto conversion.

Does that sound advisable? Not sure if the wider color space is still key for BW though.

TypothalamusAuthor

Known Participant

The other, safer, and easier way to do it is by placing flattened Grayscale images. Flat Grayscale images can be assigned a color or Swatch which can be anything. Here I’ve placed a Grayscale image, selected the image and set its color to CMYK 45|40|40|100:

So, does this route bypass Fogra conversions? Rob, I understand that the grayscale approach can eliminate color casts by defining exact CMYK values. However, determining optimal CMYK recipes for highlights, midtones, and shadows across 130 B&W images from various sources seems to require specialized knowledge. Are we assuming that Fogra 51's automated GCR algorithms will underperform in minimizing color casts while optimizing black usage?

For context, I can soft proof RGB images with Ctrl+Y to preview the Fogra 51 conversion and adjust accordingly. Does the grayscale method offer significant benefits over this profile-based approach that justify the added complexity?

While the Fogra 51 workflow includes soft proofing and a planned scatter wet proof, we may need to adjust CMY values consistently. This might require a hybrid of Fogra 51 and modified GCR, but I can’t become the algorithm myself.. The scatter proof will help us see if Fogra 51's automated method produces acceptable results, but I need a Plan B or C ready for file adjustments if necessary.

Sign up

To post, reply, or follow discussions, please sign in with your Adobe ID.

Sign in to Adobe Community

To post, reply, or follow discussions, please sign in with your Adobe ID.

Scanning file for viruses.

This file cannot be downloaded