cosnet
Member
Hi Magnus,
Sorry it took me a while to get this done even though it was an easy test and small files. Real work first!
First let me say we don't yet normalize to PDFx4. I will explain what that means in a second. Also let me also say there are a number of options in the PDF Normalizer for excluding and marking object types, etc. However, I opted to set ORIS to GCR everything regardless of overprint status, etc.
The results were interesting.
In our PDF-PDF engine, which only color corrects objects, it did not matter which file the x1a or the x4 the image part under the tint was left alone and so there is a lighter black area under the magenta tint. Also note that a PDFx4 remains a PDFx4. If the magenta box was a 4/c box instead this would have been left alone too. This is important because when you have transparencies you must maintain the visual look and the only way to do that without flattening first is not GCR it.
In our PDF Normalizer function we rewrite the PDF to make them all standard such as PDF/X1a or PDFx3, etc. I chose to create PDFx3 out of them because we don't write PDF/x4 yet. In this case the black area under the magenta tint got darker because it took the composite/flattened view of the area and so there was more gcr that could be applied.
Of course with all separations on, all the files from both methods look identical.
So which is correct? They both are but in the case of variable data you may get into an issue if you are doing plate changes only. That does not matter with either method, they both will cause a difference in the area under the transparent obect. This is why ORIS has a preflight setting that can bypass GCR if it has overprinting process colors other than black.
So the difference between the two methods: Flattening first will give you greater ink savings over the object only GCR. Both methods would introduce plate change issues unless, like ORIS (okay my pitch, ;-) ) have the ability to detect that there are overprinting process colors.
Regards,
Bruce
Sorry it took me a while to get this done even though it was an easy test and small files. Real work first!
First let me say we don't yet normalize to PDFx4. I will explain what that means in a second. Also let me also say there are a number of options in the PDF Normalizer for excluding and marking object types, etc. However, I opted to set ORIS to GCR everything regardless of overprint status, etc.
The results were interesting.
In our PDF-PDF engine, which only color corrects objects, it did not matter which file the x1a or the x4 the image part under the tint was left alone and so there is a lighter black area under the magenta tint. Also note that a PDFx4 remains a PDFx4. If the magenta box was a 4/c box instead this would have been left alone too. This is important because when you have transparencies you must maintain the visual look and the only way to do that without flattening first is not GCR it.
In our PDF Normalizer function we rewrite the PDF to make them all standard such as PDF/X1a or PDFx3, etc. I chose to create PDFx3 out of them because we don't write PDF/x4 yet. In this case the black area under the magenta tint got darker because it took the composite/flattened view of the area and so there was more gcr that could be applied.
Of course with all separations on, all the files from both methods look identical.
So which is correct? They both are but in the case of variable data you may get into an issue if you are doing plate changes only. That does not matter with either method, they both will cause a difference in the area under the transparent obect. This is why ORIS has a preflight setting that can bypass GCR if it has overprinting process colors other than black.
So the difference between the two methods: Flattening first will give you greater ink savings over the object only GCR. Both methods would introduce plate change issues unless, like ORIS (okay my pitch, ;-) ) have the ability to detect that there are overprinting process colors.
Regards,
Bruce
