Visit the new InDesign Prepress Section: Adobe InDesign: Prepress Techniques
InDesign 2.0, Spot Colors, Transparency.
In June 2001 I had the opportunity to spend some time at Australian Consolidated Press (ACP) looking at the implementation of InDesign as a replacement to QuarkXpress and Heidelberg DaVinci systems.
Replacing QuarkXpress is something that is pretty straight forward: understanding the implications with users, feature comparison, PDF generation and system requirements just some of the tasks that were looked at.
Personally, I am getting sick of so-called expert users stating that PDF does not support spot colours! This document, and InDesign 2.0, proves beyond a doubt that PDF does, in fact, support spot colours!
DaVinci system, however, are a completely different kettle of fish. These high end systems, commonly used in prepress where spot/special colours are involved require skilled operators and talent mixing artistic skills and a traditional prepress trade background.
One of the problems with tools such as Photoshop, QuarkXpress and Illustrator is their lack of strong support for jobs containing spot/special colours.
When working with bitmap images with spot colours into QuarkXpress, you must use DCS format files. DCS stands for “desktop colour separation” – applications like Photoshop take an image containing CMYK data + spot channels, and produce a file that contains all the data — but preseparated into each of the plates. After placing this element into InDesign or QuarkXpress, the only way to print high quality is to print separations.
In a world of composite Postscript and composite PDF, separated output is usually only seen at a late stage of film or plate generation. You cannot send a separated PDF to a non-print savvy client and expect a positive response.
With QuarkXpress and other applications all support a mixed CMYK + spot colour workflow. The spot colour separations are usually restricted to vector elements as created in Illustrator or the application itself. Application will generate the 5th or 6th colours when printing separations.
One “white lie” in the prepress world is that PDFs cannot retain spot colours. This is incorrect. This is a residual myth left over from the days of Acrobat 3.0 Distiller. There was a special magic trick of placing the Prologue.ps and Epilogue.ps files into the Distiller folder and turning on the “Use Prologue and Epilogue.ps” in the Distiller job options. These special .ps files can be throught of as “extensions” to Distiller. One of the side benefits was that they permitted the retaining of Spot inks in the PDFs that were generated. With Acrobat Distiller 4.0 and later in February 1999, this is not required. PDFs can contain spot colours, tools like CrackerJack and RIPs will see the extra plate and separate these correctly.
“By default, Acrobat Distiller 3.0x does not retain spot colors or separation information in composite PostScript files, but instead retains this information in the Epilogue.ps and Prologue.ps files. Separated PostScript files, however, already contain spot color and separation information, so Acrobat Distiller 3.0x doesn’t need the Epilogue.ps and Prologue.ps files. If Acrobat Distiller 3.0x uses the Epilogue.ps and Prologue.ps files on a separated PostScript file, the resulting PDF file will not contain correct spot color or separation information.” (from http://www.adobe.com/support/techdocs/1b656.htm)
When it comes to transparency, soft-edged images and drop shadows – InDesign 2.0 changes the landscape significantly. Outputting from InDesign 2.0 works today – even when generating Acrobat 4.0 (PDF 1.3) documents. The Flattener is a magic piece of work that has taken many years of advanced development. It first appeared in Illustrator 9, and received bad word of mouth. This is largely due to incorrect configuration of the Flattener settings. Personally, as these settings appeared in 3 different places, it is not surprising that it has caused heartache in prepress departments world wide. (Illustrator 9, Transparency and Printing)
InDesign 2.0 has a later revision of the Flattener, and the settings are in one place: Edit>Transparency Flattener Styles. Today people are flattening complex images: usually in Photoshop 6.0 when saving as a .eps or a .tiff. Using the Flattener in InDesign 2.0 is no different: just that it is happening at a later stage of the process. (InDesign CS Printing Guide)
What about Spot colours? Are they retained in this flattening process. It would be OK if these features worked in a pure CMYK world, but disappointing if Spots were not retained.
Yes, Spot colours are retained.
In June 2001, I sent a slightly panicky email to Tim Cole in the US:
“A slightly technical question; how will Anna deal with Spot colours?
What if I create a piece of text using a Spot Colour, and apply drop shadow? (consider shadow is a Process Black) Will the Spot be retained?”
The retention of Spot colours is highly important in the world of front covers of magazines; also packaging, outdoor/promotional posters and complex documents like annual reports.
A day later, I received the following answer from Matt, an InDesign engineer through Tim:
“The spot will remain a spot. In fact, unless specifically requested (e.g., through the ink manager, or through your spot/overprint mode selection at output time) Anna will never convert a spot to process.”
Lets look at the workflow.
- Save images from Photoshop CMYK as images with transparency defining the edges of the image(Photoshop PSD or Photoshop PDF ensuring you are Saving Transparency)
- Create and use Spot colours in InDesign 2.0 assigning colours to any elements; text etc. In this example, I have defined a large, ful;l bleed rectangle in Pantone 662C and the text “Ski NZ” in Pantone 7405 C
- Place Photoshop file into InDesign document.
- Print Composite CMYK, Separations (in the Ink Manager, ensure that the Spot colours are going to a separate plate)
- The result looks something like this:
Lets look at the Black (K), Pantone 662 C and 7405 C plates:
As you can see, InDesign 2.0 is correctly holding the spot colours, feathering the spot where the CMYK image is knocking it out, and holding the drop shadow in the Black plate.
Please note: If you have a PDF with Spot colours and transparency generated from InDesign 2.0 and are viewing it in Acrobat 5.0: ensure you have View>Overprint Preview turned on. This will ensure that you are seeing a closer representation of what is going to print. Otherwise, you will see white boxes where there is a transparency interaction.
What about composite output? Composite is usually expected to be pure CMYK. But when printing out of InDesign 2.0 as Composite CMYK, the Spot colours are held (that is, not converted to process unless you tell InDesign to do it that way). Here is a screen dump of a Composite PDF (created from Composite Postscript printed out of InDesign 2.0). To show that there is still two Spot plates, I am using Quite Revealing from Quite Software to ‘reveal’ the Spot plate.
Thanks to the guys at ACP, Tim Cole, Michael Stoddart and Matt Phillips.
A Postscript: I hear that the DaVinci’s were turned off at the end of April. All front covers of magazines, including those with spots are now completed using Photoshop and InDesign 2.0.