10 Replies Latest reply on Oct 20, 2011 6:19 AM by Ron Lanham

    SWOP to Sheetfed at last second

    Ron Lanham Level 1

      I've never had a client change the color profile just before sending to the print service so...

       

      My question is... since I've saved hundreds of images as CMYK SWOP, but the client now wants to print on a Sheetfed printer... is it necessary for me to go back and save the RGB files as Sheetfed?

       

      I've spent a huge amount of time correcting the original photos and I don't want to loose luminance or color subtleties.

       

      Thanks for any advice.

       

      Ron

        • 1. Re: SWOP to Sheetfed at last second
          Peter Spier Most Valuable Participant (Moderator)

          Necessary? No.

           

          Better? Almost certainly as sheetfed has a larger gamut and you should get brighter and more saturated colors if you re-convert. There is no point whatever, though, in converting SWOP images to SFC.

          • 2. Re: SWOP to Sheetfed at last second
            rob day Adobe Community Professional & MVP

            I've spent a huge amount of time correcting the original photos and I don't want to loose luminance or color subtleties.

             

            You made the color corrections to the RGB versions? If thats the case you can set up an action and batch convert them to sheetfed. The other option is to place the RGB files in ID and make the conversion to sheetfed on export to PDF—there's no difference in a Photoshop conversion and an export conversion if the destination profiles are the same.

            • 3. Re: SWOP to Sheetfed at last second
              Ron Lanham Level 1

              Rob,

               

              So, as I understand it, the gamut is definitely narrowed when the original RGB file is saved with a SWOP profile... right? That's what I thought, but I wanted to be sure before taking the time to reconvert all of the images. Very time consuming since all of the originals are now archived.

               

              So simply changing the profile AFTER the originals were saved with a SWOP profile won't enlarge the gamut... right? And though printing the SWOP on a Sheetfed press will still give better results than on a SWOP press... it won't give optimal image gamut since the gamut was reduced when saving from RGB to SWOP... right?

               

              If I understand... this would be analogous to attempting to bring back detail (i.e. pixels) that were deleted when an image was reduced in size... simply by enlarging the image. Once the subtleties (pixels, gamut) are reduced there is no getting them back. So it's necessary to reconvert (Adobe RGB > Sheetfed CMYK).

               

              Peter,

               

              Bear with me...

               

              You said...  "There is no point whatever, though, in converting SWOP images to SFC."

               

              This seems to contradict the above... or am I misunderstanding? Would you clarify?

               

              Thanks.

              • 4. Re: SWOP to Sheetfed at last second
                Peter Spier Most Valuable Participant (Moderator)

                > So simply changing the profile AFTER the originals were saved with a SWOP profile won't enlarge the gamut... right?

                 

                That's correct (as are the other things you said), which is why I said there was no point in doing a conversion from SWOP to SFC. All that will accomplish is simulating the SWOP colors in SFC, you won't see any improvement, so there's no point in wasting time in Photoshop working with the converted images, only the RGB.

                 

                There are subtle differences between converting to a new profile and assigning a new profile. Conversion attempts to keep the same color appearance by altering the numbers. Assignment preserves the numbers but can cause shifts in the color itself. Presuming the images have embedded profiles, it would probably be better to re-export the PDF choosing the sheetfed profile and  Convert to Destination (Preserve Numbers) which will change the values in the images to preserve the SWOP appearance (I'm guessing you did color correction), but will leave your native ID objects and type unchanged than to just print the current PDF, but it will not be as good as reconverting the RGB.

                 

                If the archived images are all in one folder, it may be relatively simple to relink back to the RGB versions using the Relink to Folder command in the Links panel flyout menu. If you did your corrections in RGB and the sizing is correct, or nearly so, there shouldn't be major differnces in sharpness over resizing and sharpening after in Photoshop, and the color will be exactly the same as if you just did a profile conversion in Photoshop without further adjustment there when you export the RGB images from ID using Convert to Profile (Preserve Numbers) and choose the sheetfed profile, but you will get better color than you have now with the original SWOP conversion.

                • 5. Re: SWOP to Sheetfed at last second
                  rob day Adobe Community Professional & MVP

                  So simply changing the profile AFTER the originals were saved with a SWOP profile won't enlarge the gamut... right?

                   

                   

                  There isn't a significant gamut difference between SWOP and US Sheetfed—the ColorSync Utility shows SWOP as slightly larger:

                   

                  Screen shot 2011-10-19 at 8.52.35 AM.png

                  Screen shot 2011-10-19 at 8.52.40 AM.png

                  Sheetfed does allow for more total ink density (350) and dot gain, so if you send SWOP to a sheetfed press you'll likely see darker images unless the press person holds back the ink (in that case you will lose gamut). SWOP top Sheetfed bottom:

                   

                  Screen shot 2011-10-19 at 9.01.36 AM.png

                   

                  Screen shot 2011-10-19 at 9.01.49 AM.png

                  • 6. Re: SWOP to Sheetfed at last second
                    Ron Lanham Level 1

                    Thanks Peter, Rob, for the great info!

                     

                    Looks like I'm going to have to reconvert since I want this project to be as nice as possible.

                     

                    I've been trying to get my client to go with Sheetfed since the project began over a year ago... and here he waited to the last second to change.

                     

                    Whew.

                     

                    Makes me think of the saying... "We can only give you what we think you said you thought you wanted."

                    • 7. Re: SWOP to Sheetfed at last second
                      rob day Adobe Community Professional & MVP

                      "We can only give you what we think you said you thought you wanted."

                       

                      If you place RGB in the layout your client can endlessly change her mind.

                      1 person found this helpful
                      • 8. Re: SWOP to Sheetfed at last second
                        Ron Lanham Level 1

                        Rob,

                         

                        I agree... I had 'simply' converted and archived the original PSD files at the very end of the project since he said he needed them sent to his printer now.

                         

                        I'd never dealt with his printer before and had very strong concerns the print service knew what they were doing (won't bore you with the details).

                         

                        I'd exported all of the files as PDFs, but was also lead to believe they might want the original ID files and thought they might muck it up.

                         

                        And when I was packaging the files ID gave me warnings about the fact that RGB files were included instead of CMYK (normally when exporting PDFs I never see this so I thought it best that I convert).

                         

                        Obviously I was wrong... ?... and do not ever have to convert unless the printing was being done directly from the ID files? ... print services still do this?

                         

                        Again... when exporting as PDF there's never seemed to be an issue... so why the warnings when packaging? Unless... again... it's perhaps for someone that would attempt to print directly from ID without first exporting as a PDF... ?

                         

                        Message was edited by: Ron Lanham

                        • 9. Re: SWOP to Sheetfed at last second
                          rob day Adobe Community Professional & MVP

                          ID can convert RGB images to any CMYK space during print as well as export—the destination profile can be chosen from the Color Management tab of the Print dialog when printing separations. If you are sending native files with RGB you do need to communicate with the printer, many still want all CMYK. The no RGB rule is a hangover from the 90s when there was no color management at print time.

                          1 person found this helpful
                          • 10. Re: SWOP to Sheetfed at last second
                            Ron Lanham Level 1

                            Thanks for the 'heads-up' Rob... really appreciate it.