Archive for the ‘ISO’ Category

Just when you’ve all cozied down with PDF 1.7 what happens?  Yes, that’s right.  A new standard rears its head.

Around the middle of 2017 the ISO committee will publish PDF 2.0 (ISO 32000-2). So by the end of 2017 you’ll probably need to be considering how to ensure that your workflow can handle PDF 2.0 files correctly.

As the primary UK expert to this committee I thought I’d give you a heads up now on what to expect.  And over the coming months via this blog and our newsletter I’ll endeavor to keep you posted on what to look out for as far as print is concerned.  Because, of course, there are many aspects to the standard that do not concern print at all.  For instance there are lots of changes in areas such as structure tagging for accessibility and digital signatures that might be important for business and consumer applications.

As you probably already know, in 2008 Adobe handed over ownership and development of the PDF standard to the International Standards Organization.  Since that time I’ve been working alongside other experts to ensure that standards have real-world applicability.

And here’s one example relating to color.

The printing condition for which a job was created can be encapsulated in professional print production jobs by specifying an “output intent” in the PDF file. The output intent structure was invented for the PDF/X standards, at first in support of pre-flight, and later to enable color management at the print site to match that used in proofing at the design stage.

But the PDF/X standards only allow a single output intent to be specified for all pages in a job.

PDF 2.0 allows separate output intents to be included for every page individually. The goal is to support jobs where different media are used for various pages, e.g. for the first sheet for each recipient of a transactional print job, or for the cover of a saddle-stitched book. The output intents in PDF 2.0 are an extension of those described in PDF/X, and the support for multiple output intents will probably be adopted back into PDF/X-6 and into the next PDF/VT standard.

But of course, like many improvements, this one does demand a little bit of care. A PDF 1.7 or existing PDF/X reader will ignore the new page level output intents and could therefore produce the wrong colors for a job that contains them.
In my next post I’ll be covering changes around live transparency in PDF 2.0.  Bet you can’t wait!
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The background
The last few years have been pretty stable for PDF; PDF 1.7 was published in 2006, and the first ISO PDF standard (ISO 32000-1), published in 2010, was very similar to PDF 1.7. In the same way, PDF/X 4 and PDF/X 5, the most recent PDF/X standards, were both published in 2010, six years ago.

In the middle of 2017 ISO 32000-2 will be published, defining PDF 2.0. Much of the new work in this version is related to tagging for content re-use and accessibility, but there are also several areas that affect print production. Among them are some changes to the rendering of PDF transparency, ways to include additional data about spot colors and about how color management should be applied.

*source: http://blog.globalgraphics.com/getting-to-know-pdf-2-0/

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ISO 12647-2 Presswork Procedure

Quite often we get the question of how to achieve ISO-12647-2 standards in press (not for certification purpose ofcourse).  So decided to write down the steps need to be followed.

1. We have to make a test form with linear plates (test form high-res file is with Mr.Saravanan of Heidelberg). A linear plate means, input and output value has to be same. If we give a value of 50%, the plate should have 50% only (+ or – 1% tolerance)

2. Print this linear plate in the press with the pre-requisites below with varied densities across the sheet

3. After the print is allowed to dry 3 hours, measure the sheet and find the optimum density for the press using Delta E and Contrast method.

4. Then print another test chart with the calculated optimal density (linear plate) and calculate the dot gain deviation.

5. The dot gain deviation has to be calculated and compensated in the RIP as per ISO 12647-2 standards

6. The same test chart to be printed with revised dot gain curve

7. The iteration should continue until the best results are achieved as per ISO 12647-2 standards

8. The Pre-press need to be set as per the “ISOcoated V2.icc” and proof need to be FOGRA 39 standard in V3 media wedge.
Pre-Requisites:

But to do the above exercise, we need to have the below

• Should have a densitometer and also a plate (Calibrated one. Prefered instruments are Ihara R730, Techkon Spectrodens for press and Ihara Accudot or Techkon spectroplate for plate dot measurement)

• you need to print minimum of 3000 sheets of your full paper size of 115/135 gsm art glossy paper with Fresh CMYK ink in the inking unit. When the target is the ISO 12647-2 standard, the used ink series should be ISO conform. Values given below for reference. We can check Ink manufacturer for the confirmation.

• The printing press has to be in a well maintained condition

• Blankets need to be in a clean and proper condition

• New blankets should be washed with water and cleaning solvent

• Verify the blanket tension with a torque key (for tension values check the machine manual)

• The Packing has to be done as per the standards

• The Pressure between blanket/plate have to be in a range of “kiss print”

• The Pressure between blanket/substrate have to be in a range of “kiss print”

• The Ink deck have to be washed clean

• All rollers have to be well adjusted

• Ink- /dampener rolls have to be well adjusted especially to the plate

• The ink distributor roller have to be checked

• Verify the machine manual for adjusting the rollers according to the machine manufacturer

• The pH-value of the fountain solution should be at a level between 4.7 – 5.3

• The percentage of alcohol in the dampening solution should be at a level between 5 – 10%

If you have any doubts are clarifications, please feel free to come back to us colorsherlock@live.com

 

The natural fibrous raw material from which newsprint is manufactured has a creamish shade due to a
content of yellow chromophores. This natural shade is more or less neutralized during the papermaking
process by the introduction of complementary blue or violet dyes to make the sheet look brighter or
actually less yellow.

ISO Brightness

The absorption of light in the untreated raw material has a maximum for blue light since blue is the
complementary colour to yellow. Consequently the light reflectance is the lowest for blue light. If the
purpose of a reflectance measurement on a newsprint sheet is to obtain a measure of the chromophore
content of the pulp, the method will be most sensitive if the measurement is performed with blue light.
This, then, is the purpose of the ISO-Brightness method in which a blue filter is used.
In newsprint production, the quantity of wood chromophores in the paper depends upon the raw material
and the process conditions. The chromophore content of the raw material, i.e. the wood, is increased and
hence the brightness is decreased with increased time in storage. In the manufacture of mechanical pulp of
good brightness it is therefore essential to use as much fresh wood as possible.
The process conditions which most greatly influence the chromophore content of mechanical wood pulp
are primarily refining temperature and bleaching. If the wood is old and dry, the refining temperature will
be higher and more chromophores will be formed. To achieve high brightness, therefore, it is essential to
avoid the use of too old and too dry wood.
The need to use increasingly larger quantities of waste paper as a supplementary raw material and the need
to close the process water system in the paper mill make it difficult and costly to maintain brightness levels
above about 55% for grammages less than 48.8 g/m
2
.

Converting raster images from an RGB colorspace into a print CMYK colorspace has two significant impacts:

1) Typically a compression and alteration of colors as the image is transformed from the original RGB gamut to the different gamut used for CMYK presswork.

2) The on-press printability of the imagery in terms of color stability, press performance/runnability, and ink usage (i.e. cost).

Converting images from one CMYK separation condition into a different CMYK separation condition by reseparating files is primarily intended to enhance the printability of the imagery while maintaining the appearance of the original CMYK
imagery. Put another way, reseparating CMYK files is effectively a way to optimize press forms.

Under Color Removal & Grey component Replacement (UCR & GCR)

The principle of RGB to CMYK separation:
In order to go to press, RGB color images must be converted to their process color counterparts; cyan, magenta, and yellow. An achromatic black channel is added because if the color black in presswork is just made from CMY it can often appear “muddy” or “patchy.” Also, making dark colors from the three chromatic process colors can lead to a higher than desirable volume of ink on the press sheet.

Neutral colors made up of three process colors are also more difficult to maintain consistent on press as solid ink densities normally vary through the run compared with a neutral made primarily of a single black ink. The net effect of introducing black ink in process printing is a reduction of ink usage/costs, stabilization of color (especially gray
tones), and and better printability.
The conversion process is done by taking the 3 channel RGB image, passing it through a 3 channel device independent CIEL*a*b* profile connection color space where the RGB is converted to CMY and the black channel added, and finally
outputting the result as a 4 channel CMYK image.

PDF Settings Download

Usually we never know what is the right settings for creating a PDF.  Please find below some of the best recommended settings.  Please download and give your feedback.

Download and Install PDF Presets
For use with Adobe Indesign & Illustrator

Download For Mac OS X (10.4 and later)

Download For Windows 2000 / XP / Vista / 7

Note: You only need to import into either INDESIGN or ILLUSTRATOR, it will share the same PDF PRESET.

1. IMPORT PDF PRESET INTO ADOBE INDESIGN

From INDESIGN at the top of the window go to > FILE > ADOBE PDF PRESETS > DEFINE > LOAD > Navigate to the PDF Preset file that you downloaded > HIGHLIGHT PDF PRESET FILE > OPEN > DONE. PDF Preset is now loaded into Adobe Indesign.

TO CREATE PDF FILE FROM INDESIGN

From INDESIGN at the top of the window go to > FILE > ADOBE PRESETS > DUKE PDF > CHOOSE LOCATION TO SAVE PDF TO > SAVE > EXPORT

NOTE: File name should not be any longer than 31 characters including the .pdf extension.

2. IMPORT PDF PRESET INTO ADOBE ILLUSTRATOR

From ILLUSTRATOR at the top of the window go to > EDIT > PDF PRESETS > IMPORT > Navigate to the PDF Preset file that you downloaded > HIGHLIGHT PDF PRESET FILE > OPEN. PDF Preset is now loaded into Adobe Illustrator.

TO CREATE PDF FILE FROM ILLUSTRATOR

From ILLUSTRATOR at the top of the window go to > FILE > SAVE AS > CHOOSE LOCATION TO SAVE FILE TO > GIVE FILE NAME > SAVE AS TYPE > ADOBE PDF > SAVE > SELECT ADOBE PDF PRESET > DUKE PDF > SAVE PDF.

NOTE: File name should not be any longer than 31 characters including the .pdf extension.

4. If you have Adobe Acrobat Distiller and you would like to import the PDF Preset. From ADOBE ACROBAT DISTILLER at the top of the window go to > SETTINGS > ADD ADOBE PDF SETTINGS > Navigate to the PDF Preset file that you downloaded. >HIGHLIGHT PDF PRESET FILE > OPEN. PDF Preset is now loaded into Adobe Acrobat Distiller.

If sheets are pulled freshly printed from the delivery and measured, the ink is still wet and has a shiny surface. While drying, the ink penetrates the paper (absorption) and loses its gloss. This not only changes the color tone, but also the density. It is only possible to a limited extent for the press operator to use densitometry to compare wet sheets with the reference values, which also refer to dry ink.

Why Polarizing filters?

To get round this problem, two linear polarizing filters at right angles to one another are placed in the path of the densitometer. Polarizing filters only permit light waves oscillating in a certain direction to pass. Part of the resultant aligned beam of light is reflected by the surface of the ink, but its direction of oscillation remains unchanged. The second polarizing filter is rotated 90° in relation to the first, which means that these reflected light waves are blocked.

Fig1. Polarizing filter

However, if the light is only reflected after it penetrates the film of ink, either by the ink or the paper, it loses its uniform direction of oscillation (polarization). Consequently, part of it passes through the second polarizing filter and can be measured.

Filtering out the light reflected by the glossy surface of the wet ink thus has the effect of making the densitometric measurement values for wet and dry ink roughly equivalent.

Brilliant colors true to the original on a premium surface – that ̓s what distinguishes a high-quality print product. Many elements in prepress and printing impact on a product ̓s color fidelity. The various input and output units in a print shop ̓s production process, consumables and other factors can cause deviations in color. A consistently employed color management system eliminates this problem.

In this series of blog tips we ̓ll show you the most common sources of error and give you tips on color management. We ̓re pleased to have caught your interest.

What is Color Management?

The color management process enables an identical color impression to be produced error-free on various output units, such as monitors, proofers and printing presses.

a. World of Color Management

With a consistently employed color management system, a template made on any input unit can be reproduced virtually identically at any output unit. Color management systems can also harmonize a range of devices, such as scanners, digital cameras, monitors, printers, filmsetters and platesetters. The color is then shown according to the print conditions, for example.

The print result is at the heart of the color management process, because the possibility of making corrections directly at the printing press is limited.