Gcr for pdf

mulo_g

Well-known member
We receive pdf artwork from customers. We send the files to our offset print service providers. Neither our offset print service providers nor do we have GCR software due to cost of investment. We wish to do Gcr to pdf's because we wish to have consistent results in printing if we repeat the print run or if we give work to different printer. Also, we believe heavy coverage of ink will give while laminating.
1. Does GCR give nearly equivalent result compared to original file?
2. Are there any cheap GCR software?
3. If we do GCR to pdf (after preflight) in photoshop manually, are the results as good as in the GCR software?
 

gordo

Well-known member
We receive pdf artwork from customers. We send the files to our offset print service providers. Neither our offset print service providers nor do we have GCR software due to cost of investment. We wish to do Gcr to pdf's because we wish to have consistent results in printing if we repeat the print run or if we give work to different printer. Also, we believe heavy coverage of ink will give while laminating.
1. Does GCR give nearly equivalent result compared to original file?
2. Are there any cheap GCR software?
3. If we do GCR to pdf (after preflight) in photoshop manually, are the results as good as in the GCR software?

If the images in the PDFs are CMYK then they are already GCR'd since the ICC profiles to do the RGB to CMYK conversion use GCR.
There are many factors that affect presswork color. So, if you repeat the print run or if you give work to different printer you may not get consistent color GCR or no GCR.
1. Most of the better file reseparating systems should give images that are reseparated that appear the same as the original images.
2. Everything is negotiable. You tend to get what you pay for.
3. No, the results from Photoshop are unlikely to be as good as would be achieved by dedicated software.

For clarification:
GCR is grey component replacement it is not a piece of software. You are talking about "reseparating" files and/or using "ink optimizing" software. (GCR Reseparation for ink savings and color stability in offset printing)
 

DeltaE

Well-known member
As Gordo said, you can use GCR (devicelink in pistop, Alwan, GMG,...) to re-caculate the color CMYK seperation for the image. But this action is only worth if your image is gray tone in major, and then GCR will show its advantage, otherwise the error of printing machine or prepress curves could destroy the accuracy of color in printout compared to the designer's idea.
Regards,
DeltaE
 

gordo

Well-known member
As Gordo said, you can use GCR (devicelink in pistop, Alwan, GMG,...) to re-caculate the color CMYK seperation for the image. But this action is only worth if your image is gray tone in major, and then GCR will show its advantage, otherwise the error of printing machine or prepress curves could destroy the accuracy of color in printout compared to the designer's idea.
Regards,
DeltaE

I do not believe that's correct. It seems to be a misunderstanding about how GCR is applied.
In a GCR separation, a percent of Black replaces, in whole or in part, one of the chromatic colors - C, M, or Y - wherever they are used together - not just where they combine to make grey. So, it has benefits for any CMYK image. GCR therefore results in more stable color on press - not just the neutrals. With well designed GCR reseparation software you should not see any difference in the accuracy of color from the original.
 

danremaley

Well-known member
Here’s my nickels worth-
GCR affects all tri-chromatic colors (Y-M-C).
The ‘graying’ component of a color is reduced and replaced with black. I.e. “reds” graying component is Cyan. Blues graying component is Mag.
GCR - “pushes” the tone scale to be more saturated or less saturated in the non-graying colors. And what do we know about saturated and in-saturated colors? They don’t change on press - it’s the mid-tone that changes!
So now the Black separation is dominant! ( before GCR was applied - it was “ghosted”)
GCR is very useful on gray images - a 50C/40M/40Y - grey is impossible to print - values near the midtone vary as the press runs - Max GCR is 50% Black only!!
Images with GCR are more stable on press.
One problem is that the Black ink is the cheapest and isn’t controlled well on press.
But if the Black varies on press what happens? The image becomes lighter or darker - no color shift - unlike when C-M-Y color shifts on press.
Call for more discussion 412.889.7643
Dan
 

danremaley

Well-known member
We receive pdf artwork from customers. We send the files to our offset print service providers. Neither our offset print service providers nor do we have GCR software due to cost of investment. We wish to do Gcr to pdf's because we wish to have consistent results in printing if we repeat the print run or if we give work to different printer. Also, we believe heavy coverage of ink will give while laminating.
1. Does GCR give nearly equivalent result compared to original file?
2. Are there any cheap GCR software?
3. If we do GCR to pdf (after preflight) in photoshop manually, are the results as good as in the GCR software?
Here is a great example of GCR - open these images in Photoshop and look at each color side by side. . .
 

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