FOOD FOR THOUGHT:
The 3 Greatest Commandments:
We all know there are a bazillion different commandments out there on how to improve print quality. Several commandments are solely dedicated to color management policies in Adobe CS products and also for a great variety of RIPs. Other commandments deal with process issues on every production departments. The rest speak of the different process controls we need to monitor at each process step.
But one fine day, not so long before, one homey went to this rabbi and asked the great teacher what the 3 most important commandments were. And the rabbi responds: Love thy neighbor's wife.....oooops!!!! Just kidding, guys.
Seriously, though: Here are the top 3....IMHO.
1. You shall keep your CMY midtone spread within 3%....preferably 1%;
2. You shall have paper according to ISO 12647-2 specified paper cast
3. You shall have inks according to ISO 2846
In my Six Sigma class we were taught one single truth: We should think in terms of "Y = f(x)". It means the output (Y) is a function of all the input (x1, x2, x3...). Which also suggests that the output (good print quality) is deterministic -- but only if all the input parameters are known....and controlled (top 3 commandments, etc...).
I mentioned these 3 inputs (x) as the most pressing issues because it give us the greatest impact, the ultimate bang for the buck, when we want to improve our PRINT quality level (Y).
Here's how to do it:
1. You shall keep your CMY midtone spread within 3%....preferably 1%
If your actual press tonal value increase (TVI) on 40% screen is C51%, M54%, Y49%....our midtone spread would be 5% (54% - 49% = 5%). That means we have to recalibrate our process to keep the distance between the MIN TVI and MAX TVI within 3%....preferably within 1%!
Keeping our CMY midtone spread very close to each other will help ensure gray balanced printing. Hopefully, a Delta C of <1.5
2. You shall have paper according to ISO 12647-2 specified paper cast
The Delta E and Delta H of our solids (C100, M100, Y100, K100) is greatly affected by the color of our paper. Using paper color other than what has been specified in the standards may result into color shifts on the press if the difference is huge. If this happens it may be very difficult, at times impossible, to match our soft and hard copy proofs with our press sheets.
The solution? It's very simple. Let's get the paper values (color cast, ISO brightness, roughness and gloss) as specified in the ISO 12647-2: Amd 1 standards and convey it to our paper supplier.
3. You shall have inks according to ISO 2846
We need to REQUIRE our supplier to provide us with standardized inks. Please take note of the following specs:
ISO 2846-1 (sheetfed), ISO 2846-2 (web coldset), ISO 2846-3 (gravure), ISO 2846-4 (screen ) and ISO 2846-5 (flexo).
Equally important is to ask the supplier to provide us with a Certificate of Analysis (CoA) as a documented proof that their inks comply with the standards. The CoA shall also include other important items (ie viscosity, transparency, tack, Delta E, etc...).
By knowing in advance the vital few inputs (X1, X2, X3...) that we need to monitor and control then our lives will surely be easier since the outcome (Y) has already been determined even before the actual production begins. This is what we call print quality assurance.
By the way, there's this 4th and final commandement: Thou shall keep your darn eyes from your neighbor's 2nd wife.