## December 2016 Monthly Focus: GV-Spectro Update

 Greetings, *|FNAME|*

Here it is, hot chocolate month! Even if you're more black coffee than hot chocolate, grab a mug, and read on about what's new at PC Industries.

 Contact PCI

176 Ambrogio Drive Gurnee, IL 60031
Phone: +1 847 336 3300 Fax: +1 847 336 3232
www.pcindustries.com

 From the PC Industries Family

Seasons greetings! As we take moment to reflect on the good times and the challenges of the year, we would like to extend our thanks to the people who helped us find health, happiness, and good fortune in 2016.

PC Industries extends our warmest wishes for this holiday season. May the new year bring the strength of family, community, and friendship for you and yours.

Debuting in mid 2014, the Graphic-Vision® GV-Spectro had a great reception in the industry as demand for inline and absolute color measurement is on the rise. Undergoing continuous development in those two years, there have been many new features introduced that have kept this system an industry leader in both performance and innovation. The GV-Spectro still offers the most accurate real-time color measurement and reporting available on the market. Paired with advanced, programmable positioning capabilities, the system is simply a staple for any printer looking for the most efficient way to get the most accurate color measurements from their press.

The newest GV-Spectro has improved system performance and efficiency without impacting the bottom line. Along with improved hardware specifications, the system now offers dot gain measurement and tracking, off-line setup, job management, and higher speed capabilities. To learn more about each of the capabilities and how they can help improve the quality of product coming from your pressroom, click below to read more.

 December InfoBYTE

Pumpkin pie. Pumpkin spice latte. Pumpkin bread and pumpkin scones. Did you say pumpkin everything? Yes, even pumpkin trivia! Are you sick of pumpkin yet?

1. Pumpkins are not vegetables but fruits, and actually considered berries.
Source
2. Pumpkins were once recommended as a cure for freckles and a remedy for snake bites!
Source
3. The name pumpkin originated from "pepon" – the Greek word for "large melon."
Source
4. Pumpkin carving originated in Ireland. The Irish used to carve turnips and potatoes until they immigrated to America and discovered pumpkins.
Source

# The GV-Spectro is More than Just Color Measurement and Reporting

Debuting in mid 2014, the Graphic-Vision® GV-Spectro had a great reception in the industry as demand for inline and absolute color measurement is on the rise. Undergoing continuous development in those two years, there have been many new features introduced that have kept this system an industry leader in both performance and innovation. The GV-Spectro still offers the most accurate real-time color measurement and reporting available on the market. Paired with advanced, programmable positioning capabilities, the system is simply a staple for any printer looking for the most efficient way to get the most accurate color measurements from their press.

The newest GV-Spectro has improved system performance and efficiency without impacting the bottom line. Along with improved hardware specifications, the system now offers dot gain measurement and tracking, off-line setup, job management, and higher speed capabilities.

## Dot Gain Measurement and Tracking

The GV-Spectro supports up to 50 dot gain measurements, which require measuring the substrate once, as well as a solid and tint of the same color.  A min and max value can be set and will be charted and displayed exactly like the ∆E and Density measurements.

## Off-line Setup

• Easily configure Step and Repeat image files (PDF/TIF/BMP) with up to 50 measurement points. Simply click and drag markers to the required areas.
• Use the configured Step & Repeat file to automatically configure the Measurement Program. Note: Unique points are required in order to map the positions correctly.
• Import CXF3 color library file containing the ‘standard’ color values & density for the measurement points, and easily link to the measurement position.
• Default values can be set
• ∆E & Density tolerances are configurable per position
• If CXF3 color library is unavailable, manual input of ‘Standard’ color values & density can be used

## Job Management

• Measurement data is saved in two formats: CXF3 & CSV.
• CXF3 = Complete group or each measurement
• CSV = Each color L.a.b, density & remission data.
• Measurement data is time stamped and can be configured to save to a specific location.
• Job Files store complete job information, including measurement positions, color values, and densities. They can be easily recalled for subsequent job runs:
• Stored on the network and shared with multiple systems
• Recalled for modifications to positions and color value

## High Speed

up to 900fpm where sample color blocks of 10mm x 10mm or larger are available (I have no idea if this is right atm)

## What is Dot Gain?

Dot gain occurs whenever ink is applied to a substrate in a non-solid ink coverage area. It is defined by the amount a digital raster dot spreads beyond its intended coverage, given in percentage. While mainly a product of paper or substrate absorption rates, there are many other factors that also determine the effective dot gain, such as plate pressure, and ink viscosity, and many ways to mitigate the effects within the printing process.

Verifying dot gain on press is an efficient way to help monitor print color quality. As dot gain increases, the perceived color in that area will often darken or over-saturate, muddying textures and obscuring details. Conversely in highlight areas where dots are very small, images can either wash out if too little dot gain or create a color cast if too much dot gain, depending on the primary color. While the human eye might be able to catch some subtle changes, electronic measurement is the most reliable way to assure that dot gain values are within what is allowed by the job specifications.

### A few notes on Dot Gain:

• Dot gain is also known as tone value increase (TVI), as it is measured based off the deviation from the desired tone, in percent.
• Dot gain is typically the largest in midtones for three main reasons:
1. The volume of ink applied is greater than in highlights
2. The amount of empty space between dots for the ink to absorb into is greater than in shadows
3. The ratio of the dot perimeter to blank substrate is most favorable for the greatest amount of ink spread.
• Optical dot gain is the apparent spreading of color due to the way light diffuses on the substrate surface before hitting your eye. It’s not a direct result of ink and paper; it’s just the nature of light. It can vary based on the reflectivity of the substrate, and is measurable. It can account for 10-35% dot gain.
• Expected dot gain varies based on substrate and tone value, with the smallest values typically being in the darkest print areas, often around 10% (depending on ink and substrate, of course)
• Most design software that is designed for professional print output has settings that will help compensate for expected image quality changes due to dot gain.

## Measuring Dot Gain

Densitometers and spectrophotometers are two tools that can be used to calculate dot gain of a printed sample.  Though neither can be used to measure dot gain directly, both are effectively capable of measuring density, from which dot gain can be calculated. These tools work by focusing characterized light onto a surface. This light is either transmitted through the substrate, reflected to the sensor, or scattered away from the sensor, depending on the type of substrate. The amount and wavelength of light that is reflected to the sensor can be used to determine several attributes about the print at that location, including density and spectral remission data.

For any spectrometer to measure dot area, the spectrophotometer must measure the density of the substrate, the density of the solid ink (SID) and the density of the tint.  These parameters are taken from color bars printed on the edge of the printed web.  There are typically more than just these 3 patch types on a color bar, but these are the most common.  Typically, the most forgotten patch is a substrate only patch. The measurement is necessary for density and dot gain calculations for ink patches, and manual measurements must be taken if they’re forgotten during calibration.

In addition to calculating the actual dot area, it is necessary to compare that to a target value. This target value, as noted above, can vary depending on substrate and other factors.

The two main measurements used to calculate dot gain are the density measurement from the area of interest and the solid ink density measurement from the calibration set. Before the final dot gain calculation is performed, each measurement is adjusted to account for the substrate density. The resulting numbers are plugged into the Murray-Davies formula, shown below:

#### Dot Area Percent= $$100* \frac{1-10^{-DT}}{1-10^{-DS}}$$

Where DT is the measured tone density (adjusted for the substrate density) and DS is the solid ink density from the solid ink patch, (adjusted for the substrate density). The result from this equation shows what percentage of a given area of print is covered by halftone dots. Finally, the ideal tone value percent is subtracted from the actual dot area percent, and that result is the dot gain for that area of interest.

## Glossary of terms

Densitometers
An instrument for measuring the photographic density of an image on a film or photographic print.

Density
Effectively, the percent of an area of the substrate that is covered by in on a given sample. However, as it is a function of light reflectivity, blank substrate can also have a density. This is why it is important to consider a substrate’s density when calculating dot gain.

Dot gain
The difference between actual and the idea percent area coverage for a halftone dot

Highlights
Typically, areas with tone values less than 30%

Midtones
Typically, areas with tone values between 30% and 70% coverage

Optical dot gain
Apparent spreading of color due to light diffusion by ink, substrate, atmosphere, or other factors.

Reflectivity
Tendency for a given surface to reflect light, or how much light that surface reflects

Typically, areas with tone values greater than 70%

Spectral remission data
Collection of data points representing the intensity (power) of light of each nm band at which a measurement is taken

Spectrophotometers
An apparatus for measuring the intensity of light the visible spectrum, especially as transmitted or emitted by particular substances.

Substrate
The material on which ink is applied