You’ve gotta keep ‘em separated – check colour separations!

There is absolutely no doubt that submitting finished artwork as PDFs has eliminated several prepress issues such as missing links and (mostly) missing fonts. Sadly, it has not eliminated all prepress issues associated with submitting artwork. In this post, I would like to look in more detail at an issue which is to me a fundamental step before submitting finished artwork, and that is checking colour separations in a PDF – properly! Not doing so is a cardinal sin of prepress.

For this, I have created a mock-up black and two spot colour flyer for a favourite destination of mine, Montréal. On face value, the PDF appears to be fine, but after looking at the artwork in more detail such as the crop-marks and where the artwork bleeds, it is clear that the bleeds will need to be fixed.

This is issue one. The rest is fine, right?

No! To see the other issues, the output preview dialog box has to be open. To get there using Acrobat 9, go to the advanced tab, then print production… , then output preview

Suddenly, the preview changes a little. From here, it is possible to see checkboxes for both process plates and spot plates. This job is Black plus two spot colours, so all appears to be right so far… but what happens when the black channel is turned off?

Instead of disappearing, the black becomes lighter. This means that the black is not purely on the black separation, but rather all of the process separations. It should look like this:

So what is going on here? It would appear that the blacks are actually made of process despite appearing greyscale, the photograph may have been RGB or CMYK. The type, despite appearing black, may be made using RGB black. So how can this be determined?

In the output preview dialog box, there is a dropdown which says “Show”. By default, the dropdown result is All, and this means that all gamuts on screen are shown, but not necessarily what images are process, spot, RGB or LAB.

If the dropdown field is changed for example to RGB, it is possible to see what items on the page are RGB only.

After doing this, it appears that the type on the page is RGB which is why it isn’t colour separating properly into black. This means going back into InDesign and changing the RGB black to 100% Black. OK, one issue, but what about the masthead picture – that isn’t RGB. It is possibly made of a “faux black” out of process, so the dropdown needs to be changed from RGB to CMYK.

I can now see two things: what appears to be a black and white picture, and coloured type in the left middle of the page. To determine if the black and white picture is actually on the black separation only, the black separation has to be toggled off.

The image has become lighter, but not disappeared. This tells me that the image is made out of process instead of being greyscale. This means going into photoshop, making the colour mode greyscale, resaving, relinking in InDesign. That is two issues.

But why was there process coloured type? It should be two spot colour separations plus black. To check this, change the dropdown field to spot colour.

Now I can see the word Montréal in solid 494, the background in a tint of 494, and the strip of yellow 610. But the words “WHEN SHOULD I GO?” have disappeared. This infers that these items were not made out of spot colour, or they should be visible in this view. Instead, the items must be made out of process, as they were visible in the CMYK view, but not Spot Colour nor RGB views.

So after checking the PDF and its separations more thoroughly, I now know there are several fixes required for this PDF: The InDesign file needs to have the following changes:

  • Colour which extends past a trim area has to bleed off;
  • The RGB black type needs to be 100% black only;
  • The “black” photo of Montréal needs to be made greyscale;
  • The words “WHEN SHOULD I GO?” and yellow strip behind need to be changed from process to their appropriate spot colours.

I have prepared before and after PDFs for the purposes of trying what has appeared on this post.


Spot “color” of bother

Why converting spot colour to process on process artwork is not such a good idea.

Ever had a supplier make contact to say that there are spot colours in the artwork supplied, and wondered “Why don’t they just convert it and leave me alone? Why are you bothering me with such a simple thing?”

1) Possible breakdown in communication

For the art department of the supplier, this will normally be the first time that they have seen the artwork and be totally unaware of its history or construction. All the art department will normally be concerned with is that the details on the docket match the artwork, and that the artwork meets the mechanical specifications for the press, such as correct colours, bleeds, page size, etc.

For a prepress operator, observing a spot colour in addition to process artwork raises red flags such as:

  • Is the artwork actually meant to be CMYK+spot?
  • Is the artwork meant to be all spot colour?

Similarly, if a prepress operator receives artwork with instructions that the artwork is to print in Pantone Red 032 for example, but the file is prepared in Pantone Warm Red, the prepress operator will ask the question: is the colour being printed on the docket correct, or is the ink in the customer’s artwork correct? This is not uncommon problem in a printing business and is a great way of delaying proofs and creating confusion.

2) How the conversion is done

“Converting” a spot colour all depends on how the conversion to process is done. Take for example the color Pantone Red 032. Depending on which application made the PDF, the colour can appear with several breakdowns:

  • Adobe InDesign 5.0 (Pantone Solid Coated Library) – C0 M90 Y86 K0
  • Adobe InDesign 5.0 (Pantone Color Bridge Library) – C0 M90 Y60 K0
  • Quark Xpress 8.0 – Solid Coated Library OR Color Bridge (using the CMYK output) – C0 M90 Y60 K0
  • Quark Xpress 8.0 (using the CMYK and spot/As Is methods) – LAB colour

In addition to this, the printer’s RIP also has the ability to convert spot colours to process in a PDF based on the alternate value within the PDF, or a value based on a spot-to-LAB-to-CMYK conversion.

Furthermore, a customer’s corporate stylesheet may have several colours of a logo depending on the circumstance that the artwork is being used, such as:

  • if appearing in newsprint in process, use this breakdown;
  • if appearing on glossy stock in process, use this breakdown;
  • if appearing in newsprint in spot, use this spot colour;
  • if appearing on glossy stock in spot, use this spot colour;

3) If the PDF has transparencies, drop-shadows or the like.

If the PDF has been made to Acrobat 4 compatibility (1.3) and features drop shadows or any effects above a spot colour which was flattened once the PDF was made, then a spot to process conversion may not even be possible. Areas which were flattened will become white, as demonstrated in the illustration below.

4) The client’s expectations of spot v process

Some spot colours such as metallics, fluoroescences, pastels etc convert terribly to process, regardless of which method to convert them was used. If the client has chosen spot colours from a swatch book with no process equivalent next to the swatches, and expects these colours to reproduce out of process colours and look identical to the swatch book, then they are setting themselves up for failure.

Some swatch books (such as Pantone Color Bridge) does display its swatches with the spot colour on the left and how it appears converted to process on the right.

However, if a customer is shown a swatch using the book and it is not made clear between the difference in colour between spot and process, the customer will be disappointed once again.

The bottom line?

If artwork is to print process, prepare the artwork using process colours only. If the artwork is to print in spot colours, make sure that the spot colours in the document are going to be the same spot colours going to press. If your client has supplied you spot colour artwork which should be process, ask them to supply process artwork. If they complain and ask why, point them to this article.

The name is Preview… Separations Preview

Despite this magnificent feature being introduced since the first release of Creative Suite, I am still amazed at the amount of people who either don’t use this preview, or know it exists.

For those who don’t know what i’m talking about, Separations preview is a way of viewing the InDesign file so that it more closely resembles what it will look like once printed. It also lets users toggle through the ink separations which are available in the document.

Using separations preview it is possible to determine common prepress errors such as:

  • Unwanted overprints, such as white overprints suddenly disappearing from view;
  • Items set as either non-printing objects or non-printing layers (they will disappear completely from view);
  • Undesired black overprints, such as a solid black overprinting a photograph and still having the photograph visible instead of knocking out;
  • With the exception of photographs – real blacks instead of faux blacks (e.g. items meant to be 100% black only but instead composed of all four process colours);
  • Effects which won’t work with spot colours such as color burn, soft light or overlay (the areas over spot colours using these effects will dissappear);
  • The use of Registration colour (will appear on every single separation as a solid);
  • Any spot colours which shouldn’t be in the document – either because they aren’t actually in the design but are still in the swatches palette; or if they were meant to be converted to process using the ink manager;
  • Unwanted knockouts, such as a dieforme overlay which wasn’t set to overprint and has knocked out the artwork underneath it.

Similarly, Adobe Acrobat has a separations preview but goes some steps further such as:

  • How the artwork will appear based on different colour profiles; or to simulate black ink and paper appearance;
  • Can show whether the images in the PDF are CMYK or other colour spaces, such as LAB, RGB etc.

This is only using separations preview as well… haven’t even mentioned the Ink Limit view available in both Acrobat and InDesign; or the Flattener preview available in InDesign… but will save them for another post.

“Spot” the difference of soft light with overprint preview

I recently found myself being the “bad guy” after having to instruct a customer to resupply their artwork given that many of the effects applied to the pictures in InDesign would not print as desired.

In short, the artwork was an annual report printed in full colour plus a metallic silver spot colour. Originally supplied PDF only, everything looked fine on first glance with the overprint preview off. However, while the document was being manually preflighted using Acrobat’s Output Preview, I had noticed that a greyscale-like effect on the silver had disappeared once I had entered the Output Preview. Concerned, I restarted Acrobat to make sure the glitch was not software related, but again the same thing appeared. This happened on several machines and it soon became apparent that the artwork would in fact print as it appeared in Output Preview rather than the normal preview.

The customer was then contacted and informed of the situation. After replying that the artwork looked fine on his screen, the customer was then instructed to turn the overprint preview on within InDesign, and lo and behold… he began to see what I saw. He then told me he had used the soft light effect.

To demonstrate the phenomenon, I have created a new InDesign file with five elements: a rectangle coloured with Pantone 871C; a rectangle coloured with the default green which ships with InDesign; a stock photo with the soft light effect applied , and two captions of the colours in the rectangles. In the before image, the Separations preview is turned off.

and this is how the InDesign file looked after the separations preview was turned on:

resulting in the image disappearing from Pantone 871C rectangle. However, the image still appears over the process green rectangle.

Ultimately, this means that the effect is only reproducable over process colour, and not spot colour, regardless whether it is metallic or not.

Interestingly as well was the fact that in Live preflight, there was no error warning of this particular feature of the soft light effect, so if I was purely to obey the live preflight and not check my file with the separations preview or overprint preview, this would have been completely missed.

The lesson here? Always check artwork using the separations preview to make sure the artwork will appear as designed, and that some effects will work in process only.

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