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Colour Matching
COLOURS - Process Colours
Most customers will select their process colours in several ways.
They'll adjust the CYMK values on screen until they are happy with the result.
Although this method is great for getting a great looking job on screen, it falls down in several areas. Every Mac or PC will have a different monitor and gamma settings. Try it for yourselves - open the same file on several computers and compare the difference. A calibrated state of art monitor will help but even the best ones are only simulating CMYK out of RGB.
A colour print out.
This can vary from printing a proof on a cheap and nasty desktop inkjet to a full service output bureau with a calibrated digital printing press. Again although useful they are not 100% accurate. Even the most expensive plotter proofs will not give you an exact match for colour. When colour is critical - we offer a test swatch service; this is by far the most accurate way of testing colour.
The Worldwide Process Colour Finder.
An experienced artist will be able to sample areas of colour in a file and compare that against the same value in our colour finder. This allows you to see how the colour will be affected by the various papers. We encourage using the Worldwide colour finder. It will make your life easier and it can be one of your biggest selling tools. Read more...
Match to existing colour or match or a Pantone number.
Again an experienced artist will be able to match these colours using either the process equivalent to the Pantone number or by selecting the nearest colour in our Process Colour Finder. Please note Pantone often revises the CMYK colour splits of their PMS colours. Example if you get the Pantone CYMK reference for Reflex Blue from Adobe CS1 and then find the same split in CS2 you'll notice the values have changed. This is not an Adobe program error but simply Pantone changing what CMYK splits they think best matches their PMS colours.
While Worldwide Online Printing has some of the most exacting colour standards in the world it is advised that you are aware there are variables that can change the colour slightly from batch to batch and a 100% exact colour match can't be promised.
COLOURS - Useful Process Colour Splits
When you require a LARGE AREA of black on a print job we suggest using either Special Black or Super Black. These blacks are not recommended for body copy black text but are suitable for large text headings.
Some useful, process colour splits are:
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Red: 100m 100y Orange: 50m 100y Gold: 25c 30m 80y
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Blue: 100c 90m Green: 75c 100y Silver: 7c 30k
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Drk Blue: 100c 90m 20k Lime Green: 40c 100y Bronze: 34m 83y 15k
Many stores request the colour splits used by the Marketing Department in Worldwide printed material. The most common is the bluey grey used on our Business Cards.
Do not use Registration as a heavy black. Artwork sent to Pre-Press with large areas of Registration will be rejected. The maximum Ink coverage accepted by our presses is 240%. You can check this by using the Maximum Ink coverage setting in Acrobat Professional 7 under the Advanced/Output Preview option.
Caution:
When you select an area of black in some layout programs and in Acrobat, the default setting is set to overprint. If you manually change individual object colours their overprint setting will not change. Double check this by viewing your PDFs in Acrobat with the overprint preview option on.
Example 1: Text is changed from Black on Yellow background to Magenta on Yellow and overprint is left on: Text will print Red.
Example 2: Text is changed from Black on White background to White on Black background and overprint is left on: Text will NOT PRINT. This is a quite common problem and unfortunately it is not something a flight checking program can easily pick up.
Caution: When converting PMS colours to process, please be aware that some programs have different conversion tables. E.g. Adobe CS1 and CS2 are different) Try converting Reflex Blue with InDesign CS2 and then try converting the same colour using Pitstop. The same can be said when RGB colours are converted to CMYK, the result can differ depending on the look up table or colour profile used by each program.
COLOURS - Spot Colours
All spot colours must be named as a standard Pantone colour.
E.g.:
Standardise the use of CV, CVC or CVU in your documents. All components of a job should have the same colour suffix. It is better to select from a Pantone colour swatch, being aware that colours can vary from stock to stock especially if you change from a coated to uncoated paper.
IMPORTANT - Wherever possible print out a colour split file and compare the separations against the composite artwork. Alternatively use the Overprint and Output Preview features in Acrobat 7 to view the final file. (Under the ADVANCED menu)
If you select a Pantone colour but you wish the file to be printed in process colour you should enable the convert to process colour option in your layout program.
PLEASE NOTE: the process equivalent of some Pantone colours is very different to the Spot Colour versions. Check therefore the Pantone Colour Bridge (Spot to Process comparison) colour guide. It is important that you check the values of these conversions as Pantone change their % values on a regular basis. If you have a Pantone Spot - Process swatch book, make sure it is current and it has the same colour splits as your software.
Trapping
Trapping can help compensate for registration problems by slightly expanding one colour into another and eliminating the gaps and colour shifts between colours. For trapping to be effective, it must compensate for less than perfect registration without forming noticeable lines of unrelated colour around objects caused by the overprint. Process colours that share a sufficient percentage of common colours do not require trapping, because any registration problems will reveal a colour that is similar to each of the adjacent colours. An example of where trapping would not be necessary would be a printed item containing mostly reds and oranges. If the object on such a page were not in perfect register, the result would not be visually distracting because the colours in the gaps and overprinted areas would be similar to any adjacent colours.
The sequence in which the process colours are printed also influences ink trapping. For standard four-colour printing, the correct sequence to print the process colours are black, cyan, magenta, and finally yellow. Printing the colours in the correct sequence will help ensure the best results. A change in the standard sequence will result in a change in the ink trapping characteristics.
In the Worldwide production hubs we run an automated trapping extension as part of our Celebra RIP. This has been set up to give us the optimum results on our typical ganged up sheets. It's not perfect for every single job but gives us satisfactory results on 99.9% of jobs going through the hub.
Please note: the trapping can only take place on vector artwork, bitmap images are not trapped. Were this can cause a problem is when a series of items are flattened together as part of the PDF production process. What can happen is that half a sentence of text will be vector and subject to trapping and the other half will have been converted to a bitmap image and will not trap. The result is what looks like half the text is bold and half isn't. This sort of problem usually only ever gets picked up when looking at the final print job. The only way around this is to not trap the job or it sometimes helps if the text is placed on a separate layer above any bitmap images during the artwork stage.
COLOURS - Non Printing Colours
At Worldwide we standardise the use of non-printing colours in the respect of how they are used.
RGB - Red
This colour is perfect for adding "read me" files and important messages to the pre-press staff. Use as a spot colour set to overprint.
EG: Non standard Trim to 50 x 90mm
Please check against supplied sample.
RGB - Blue
We use this as our standard cutter guide colour in folders and calendars.
Solid line for cut.
Dashed line for fold or score.
Use as a spot colour set to overprint.
RGB - Green
Perfect for use as a spot UV mask or embossing template.
Use as a spot colour set to overprint.
It is important that the standard RGB colours are never used as printed colours. Viewing a file on screen and expects the vivid RGB colours to look the same on a printed job might cause disappointment.
Paper Stock
The type of paper you choose for print can influence a colours' appearance, reflecting the overall quality and finishing involved on the job.
Paper sizes, from A6 up to A0 include the most common sizes in printing - A4, A3, and poster sizes A2 & A1. But A3, A2 & A1 also refer to the quality of the paper.
A3 is a low grade product seldom used in commercial printing while A2 is good commercial quality and used in most Worldwide print jobs. A1 is the best quality. With a higher percentage of coating to produce less dust and finer print, it is the most expensive but produces the best finish and is a good choice for speciality jobs. Consider the finish on the paper for each job; gloss or dull surfaces can enhance or detract from the image/text being printed.
Sometimes, printing the file digitally on both types of paper can help determine which will be best suited for a particular use. Knowing how the product will be used is vital when selecting stock, particularly in regards to writing or for use with a desktop printer. You will find that it is very difficult to write on a celloglazed coating. And a letterhead on anything other than an uncoated stock gives it a completely different appearance.
Rule:
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Writing: uncoated
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Letterhead: uncoated
Uncoated is not to be confused with dull. Dull, like gloss, has a coating. Look in your paper samples for examples of different finishes. Take a look at A13 (blue shade printed on 90gsm Opal Laser - a porous uncoated paper used extensively for letterheads) and compare it to the same value on 300gsm Sapphire Art Gloss with a Matt Celloglaze coating. The same CMYK values - C100 M100 Y0 K50 appear different when printed on different stock and/or with a coating. Always consider how a stock will best represent the artwork when discussing colour, logos and different stock options.
Paper Weight
All paper is weighed in grams per square millimetre; is not a measure of paper thickness. This is due to different manufacturing procedures including the amount of paper pulp that is pressed to make the product. You will often find the higher the quality paper, the less rigid it feels compared to a lower quality stock of the same weight.
Worldwide business cards are generally printed on 300gsm gloss board, and letterheads on 90gsm Worldwide Laser - a stock developed especially for use in a laser printer. As with most stocks, Worldwide Laser is also available in heavier and lighter weights (GSM).
Paper weight becomes crucial when printing double sided.
Worldwide Laser when printed both sides does tend to give 'show through'. Selecting a heavier grade (higher GSM) will help to avoid this.
Paper Cracking
The coating on dull and gloss paper and board is prone to some cracking when folded. This is normal, but appears more obvious when dark or solid colour is used across the fold. The problem can be alleviated with scoring and laminating, or avoiding heavy colour use over the folded area (especially dark/solid coverage).
When printing multiple up jobs on one sheet, you must ensure the fold is running the same way as the paper grain, otherwise cracking will occur. If you aren't sure how the grain will run, contact CPD and discuss the layout with them. Note: Any stock 170gsm or heavier requires scoring if it is to be folded. You may need to add this to your quote notes as an extra finishing on the quoting system.
Preparing Artwork for Offset Print
When preparing your files for offset printing, make sure to study the quote or brief sheet. This will contain all the specific information pertaining to the size and attributes of the art. A thorough understanding of the requirements, including any additional finishing, is necessary to make sure the job has been set up for print correctly.
Templates
Every standard offset job must be set up on a Worldwide template. The template facilitates the step and repeat function of the plate setter so jobs printed multi-up can be accurately positioned with 2mm bleed. All templates can be downloaded from the Worldwide website, in QuarkXpress and InDesign formats. The template is essentially the document size plus 2mm bleed, but there are some exceptions. i.e. business card templates, which have extra space in a non-print area indicating the 'head' position (orientation). Artwork for standard business cards must be centred in the template. Our templates are unique, containing a 20% Yellow 0.5 pt key line at the outside edge of the document. This indicates to the guillotine operator that it is necessary to trim 2mm inside of this line. If possible set up your artwork up using the Worldwide templates. This will save time, and assuming the file flightchecks ok, the job can be dispatched much faster. Odd Sizes on Standard Templates
- If a file is a non-standard size, you can still supply it on a standard template, but:
The trim size must be indicated with trim marks, and the print order 'order memo' field must show the finished size for trimming.
Odd Sizes on Non-Standard Templates
If a file is being printed at an odd size as a non-standard job, you can create your own template by adding the customary 2mm bleed to your document size, indicating the trim with a 20% Y 0.5pt key line bordering your document. The prepress operator will then step-up your file for the most efficient print run. Some small items such as swing tags, display cards etc, can be imposed many different ways as non standard jobs.
The file can be submitted as above, or you can set the file up yourself, step-up according to how it has been quoted. i.e. x up on A4 or A3 (this method is not recommended for A2 + printing). | 
Digital Printing
