Archive for the ‘ICC V4’ Category

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

 

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Version 4 of the ICC profile specification was published in 2001. The v4 profile format has introduced a number of changes when compared to the previous v2 specification. These changes provide a number of advantages, the most significant of which follow from the removal of ambiguities from the specification and a more precise definition of the PCS. More information about the advantages of the V4 specification can be found here.

These lead to an improved predictability of performance of a profile in use which will lead to a reduction of major differences of interpretation. Therefore, when pairs of profiles are used they should always produce the same result – regardless of which CMM is used. A summary of reasons to use the v4 specificationis available.

ICC – International Color Consortium

As color management requirements evolve, the profile specification undergoes a process of continuous review by members of the ICC. The current version is ICC.1:2004-10 (Version 4.2.0.0) and is available on the ICC Specification page, together with Amendments approved by ICC members.

The specification has been approved as an ISO standard (ISO 15076) and the version on the ICC Specification page is compatible with the ISO publication.

Most platforms and color management applications have now migrated to ICC V4, or are in the process of doing so. You can test whether your system is V4-compatible here