Saturday, January 24, 2009

Aligning proof and presswork

The process of aligning proof and presswork generally follows the basic steps outlined below. This procedure applies primarily to Strategy One as outlined in my January 18, 2009 blog posting. However, it can certainly be modified to for Strategies Two and Three.

01) Identify the target for your presswork. This can be an internal standard or industry specification (e.g. ISO, GRACoL7, SWOP, etc.)

02) Get consensus and buy-in from the stakeholders (prepress, pressroom, management). Change is always disruptive, however, if everyone affected is on board you will have a much better chance at success.

03) Determine who's going to be the lead implementer (i.e. internal resource or outside consultant will be used). Be honest in your evaluation of internal competence. Recognize that if you do it yourself, even if you fail, you will get a greater understanding of the process and therefore be in a better position to evaluate an outside resource should that end up being needed.

04) Open a docket. The process will consume company resources which need to be accounted for. Also the project will need to be treated seriously and given the proper time and involvement. Dockets help to ensure that happens.

05) Contact your ink vendor to determine if your current inks can achieve your target. If not, identify with your supplier, an ink series that has proven capable.

06) Contact your proof/workflow vendor to determine how to set up your proofer to output proofs that align to the industry specification you have decided on.

07) Find a paper for your press that aligns to the brightness defined in the specification. Try to find one that has a similar UV optical brightner content to your proofing media. You can use a $10 black light to do a qualitative comparison. Make sure the bulb is fluorescent not incandescent. Proof and press paper should glow, or not glow, by about the same amount. If there is a big difference with your press/proofer paper in terms of optical brightners used you will have problems.

08) Confirm that instruments used in prepress and pressroom are in proper working condition, calibrated, set to the same standard, and agree with one another.

09) Confirm that your CtP device imaging is consistent, across the plate and plate to plate. Consistency is more important than accuracy.

10) Test the press. This involves running a test form, preferably without images or proof, to determine the mechanical/chemical soundness of the press. If the press not stable that will need to be addressed first.

11) Assuming that #10 was a success (with your inks and papers) and that you were able to hit the required CIEL*a*b* values at the appropriate solid ink densities - then build plate curves to align the tone response of your presswork to your proof.

12) Go on press to confirm alignment between proof and press sheet. For this test form you can add subjective reference images to your objective measurable targets.

13) Assuming that #12 was a success. Catalog and document plates, proofs, and presswork. This will become your "golden reference." If anything goes wrong in future production, you would run this golden reference to determine what has changed.

14) You may, optionally, characterize your presswork and use the resulting profile to fine tune your proof to your press that is now conforming to the industry specification.

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