Proofing is a word that means a lot of different things. Softproofing for example, is finally available and so precise that press sheets are matched to monitors. Inkjet proofs can achieve a match of greater than 98% consistently and have become today’s contract proof. Some inkjet printers have sophisticated built-in color management including a spectrophotometer. And laser printers who could never produce accurate color consistently are finally reliable for fast, high-volume accurate prints.
On press, things move all the time. Standards are constantly questioned and new methods developed. Do you go with SWOP or with G7? Or both? Should you accept a file displayed on a monitor as a contract to match on press? Who decides what the standards will be and how do you make sure that your file is correctly printed?
Traditional printing specifications such as SWOP or SNAP are used as a de facto industry standard to define print quality but most printers use these specifications as a starting point to develop their own “in house” standards with often inconsistent and unstable results. G7 methodology is the first to efficiently and reliably match the visual appearance of multiple devices by defining gray balance and neutral print density curves instead of the traditional method of measuring TVI (dot gain) for each color. Curious about G7? We’ve asked our experts ten questions. Their answers will tell you if GRACoL7 is right for you.
- What is the difference between GRACoL, GRACoL7, and G7?
What is a traditional press standard based on?
- GRACoL is a set of specifications for commercial printing developed by the GRACoL committee, a member of IDEAlliance
- GRACoL7 is the latest version of these guidelines
- And G7 is the methodology used to meet these specifications
What are the limitations of traditional press control?
- SID (Solid Ink Density)
- TVI (Tone Value Increase or Dot Gain)
- Wet ink trap
- Print Contrast
What are the advantages of the G7 method?
- SID specifications do not reflect an individual press’ capability
- TVI is set to different values for different printing processes (i.e. sheetfed, web, newsprint)
- TVI and SID do not define the appearance of color on press
Why is Gray Balance important in evaluating a press sheet?
- G7 measures substrates and colorants using colorimetry rather than density
- It uses gray balance as the primary control measurement
- It establishes a Neutral Print Density Curve (NPDC) as a target for the reproduction of highlights and shadows
- Although they remain important metrics, SID and TVI are no longer the primary process controls
Why is it better to use colorimetry than density?
- Because when neutrality is defined and maintained, color will usually look correct and stay consistent through a press run
What is a Neutral Print Density Curve (NPDC)?
- Because colorimetry considers color and color balance rather than the weight of ink on paper
- And because it gives the ability to define the appearance of color and to monitor color change
How is Highlight Range (HR) used for process control?
- NPDC is a target curve defined along the entire tonal range. GRACoL7 defines a specific NPDC curve that allows the press to run to its natural tendencies, using plate compensation curves to correct for unwanted behavior.
- It uses the entire tonal range not just the traditional TVI 25%, 50%, and 75% values, giving you the entire shape of a curve, from highlight to shadow
What are the benefits of the G7 method? They are:
- As a quick check to visually compare a 50/40/40 CMY patch to a 50K patch
- As an additional checkpoint, to check gray balance in the 50/40/40 CMY patch
- And to monitor the TVI of the press run
Am I a good candidate to switch to G7?
- Faster make-readies because the press operator can quickly determine the ink balance on the sheet using neutral and black patches
- Better control on press because G7 uses colorimetry
- Gray-balanced plate curves improves the press’ ability to print neutral through the whole tonal range
- Yes, if your color make-ready is taking longer than you’d like
- And if you want to spend less time measuring press sheets
- Also if your customers complain about the quality and the consistency of your color
- Or if you need to match color appearance across multiple presses or press types.
Rods and Cones, Inc.: Perfect Color and Custom Workflows
We will get a match between monitor, printers and presses and we’ll make sure that your workflow is the most efficient in terms of time and cost. We can advise you on what printer is best for you, whether you need a RIP and which one, and if you would do better using the G7 method on press.
To get the most out of your resources, bring us in to evaluate your workflow. If in need of something more efficient, we’ll design a new workflow especially for you. Our proposal is backed by a ROI, technology, and the most seasoned workflow experts.
Contact Rods and Cones, Inc. at 831-421-0131.