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R730 Color Reflection Densitometers

R730 Color Reflection Densitometers

The model R730 color reflection densitometer is our most advanced densitometer utilizing the latest technology to ensure great accuracy, inter-instrument, and repeatablity. This instrument combines functionality and simple user interface in a small, lightweight design.

The model R730 measures: Density, Density Difference, Dot Area, Dot Gain, Ink Trap, Print Contrast, Hue Error, Grayness, Brightness, Cast, Saturation, Dot Anaylysis, and Auto Function.

Features:

  • Simple user interface with self-guiding prompts
  • Menu-driven display guides the operator through calibration, set-up, and all measurement functions
  • Extremely reliable and requiring little or no maintenance
  • Multiple language user interface supported (English, Spanish, Portuguese, French, Italian, German, and Japanese)
  • Easy and low cost maintenance
  • Manufactured in Japan under ISO 9001 certification

Accessories

  • Operation Manual
  • Calibration Standard
  • AC Adapter (9V, 500mA, center-negative)
  • Carrying Case
  • Serial Interface Cable (Optional)
  • Cable Harness (Optional)

Features / Measurements


DENSITY

Densitometers do not actually measure ink thickness, but rather measure reflected light. A logarithmic equation is used to calculate density from the light absorbed by the surface. To calculate the absorbed light on a surface, the difference between the light reflected back from the surface and the light supplied by the densitometer is used.

Densitometers calculate density by using this equation:

Density Equation = log10 1/R, where R= % Reflection

% Reflectance DENSITY
100% 0.0D
10% 1.0D
1% 2.0D
0.1% 3.0D
0.01% 4.0D
0.001% 5.0D
0.0001% 6.0D

As you can see the equation is logarithmic, which converts into the values shown on Table 1. To explain the Table further, it can be understood as a density of 1.00 is reflecting 10% of the light.

Your density reading is a guide to keeping your ink level monitored and consistent. In doing this throughout your press run you can detect any changes that could alter your print quality and allow to provide quality control over maximizing the use of your inks.

Below, are some typical wet ink densities, to follow as guidelines.

  BLACK CYAN MAGENTA YELLOW
SHEET-FED, OFFSET 1.70 D 1.40 D 1.50 D 1.10 D
WEB-OFFSET, Magazine 1.55 D 1.30 D 1.40 D 1.00 D
NON-HEATSET WEB, Newspaper 1.05 D 0.90 D 0.90 D 0.85 D

Table 2: GATF-Measurements were made using a Status-T densitometer, and the density of the paper was included in the measurement.

Most densitometers give you the option to include or not include the density of your substrate into your reading. If you chose to include the measured density of the substrate or base along with the ink sample, this is known as Absolute Density. If you subtract the density of the substrate from the density of the ink sample, this is known as Relative Density.


DENSITY DIFFERENCE

Density Difference allows you to establish a reference density and compare this to a sample density. Say you choose your reference color and it reads Yellow 1.05D. Now, take a reading of your sample color- say it reads Yellow 1.02D. The densitometer will subtract your reference color from your sample to show the difference between the two densities. In this example, your Sample yellow deviates (-0.03D) from your Reference yellow.

Many times the naked eye is not enough. Two colors may appear to be identical when in reality they are not. You may notice changes in your image, yet you feel your density value has remained constant. The density difference function helps aid in these situations.


DOT AREA

Keeping your dot size consistent in printing is very important. If your dot size changes throughout your press run it can have drastic effect on your image. For this reason, most densitometers provide you with dot area. This is an estimated percentage of the dot size on your print.

Changes in dot size can be the most common problem to incorrect color. In using the dot area function, the densitometer allows you to keep a monitor on your dot size throughout your press run so you can keep your color consistent.


DOT GAIN

Dot gain occurs when wet ink comes in contact with paper. As the ink dots are applied to the paper, the wet ink spreads, causing the dots to increase in size and appear darker, the size of the dot changes. This occurs in any printing job, however, the goal is to keep your dot gain consistent. For example, if the original had a dot area of 50% on the film and the resulting printed dot area was 68%, the dot gain would be 18%. Generally, the higher the screen ruling, the higher the dot gain. The densitometer will compute percent dot area and then the coverage of the printed image, thus comparing these readings to display dot gain.

As with dot area, almost any job allows for dot gain, however, if this number fluctuates or changes in any way during your press run, it can cause colors to change.

The table below shows some typical Dot Gain values for three common printing conditions.

  BLACK CYAN MAGENTA YELLOW SCREEN RULING
SHEET-FED, OFFSET 40% 36% 36% 30% 150
WEB-OFFSET, Magazine 36% 31% 31% 28% 133
NON-HEATSET WEB, Newspaper 24% 22% 22% 18% 85

Table: GATF-Measurements were made using a Status-T densitometer, and dot gain was calculated using the Murray-Davies Equation, measures at the 50% film dot area.


INK TRAP

Ink trap refers to how well one wet ink can grasp and hold to the second ink that is printed over it. You want your two inks to hold well together, if they don't it can damage your image. It is for this reason, that you want your two inks to adhere as optimal as possible, but not to over maximize your trap. Trap values are measured in terms of a percentage. A high percentage is "good" because it stays true to the favored color. A low percentage, (typically, below 65%), which gives uneven color, is considered "poor".
Be careful, poor trapping can result in a color shift.

Your trap value will help you in obtaining the best color image by providing the maximum trap. In addition, it helps to aid in detecting faults with your ink, such as poor ink tack and ink absorption.

The table below shows some typical trapping percentages.

  RED GREEN BLUE
SHEET-FED, OFFSET 70 80 75
WEB-OFFSET, Magazine 65 75 70
NON-HEATSET WEB, Newspaper 55 65 60

Table: GATF-Measurements were made using a Status-T densitometer, and trapping was calculated using the Preucil Trap Formula. The ink sequence was cyan-magenta-yellow.


PRINT CONTRAST

The better your image can hold shadow detail the better your print contrast will be. When you have high print contrast values your image will appear richer and more brilliant. If your Print Contrast values are low your image will appear neutral. You want your print to have as high a contrast as possible, however, if you increase the ink too much, it can become blocked up and you lose your dots. The Print Contrast function, provides you with your contrast values as they increase, and then the point at which it begins to decrease, this allows you to reach your optimal density for optimal contrast level.

By using the print contrast function, you will be able to achieve the maximum contrast from your image.

The table below shows some typical Print Contrast values for three common printing conditions.

  BLACK CYAN MAGENTA YELLOW SCREEN RULING
SHEET-FED, OFFSET 40% 36% 36% 30% 150
WEB-OFFSET, Magazine 36% 31% 31% 28% 133
NON-HEATSET WEB, Newspaper 24% 22% 22% 18% 85

Table: GATF-Measurements were made at the 75% dot area using a Status-T densitometer.


HUE ERROR

In the real world, you cannot find a perfect process color. Hue is how we identify the color of an object, or printed area, such as cyan, magenta, or yellow. Hue Error represents the deviation from a theoretically perfect or ideal cyan, magenta, or yellow. For example, a printed solid patch of cyan has some magenta and yellow. Your Hue Error value will compute the deviation of your Hue shade from the additional two inks. This function is good for comparison of inks from different manufacturers or between different deliveries of ink from the same supplier. This measurement aids you in checking consistency of your inks from batch to batch.

By using the hue error function, you are able to monitor and record the variation of your ink from an ideal ink. This information can be transferred to the color separation process so that you can adjust your films to obtain maximum results with your color.

The table below shows some typical Hue Error values for three common printing conditions.

  HUE ERROR
  CYAN MAGENTA YELLOW
SHEET-FED, OFFSET 20 46 5
WEB-OFFSET, Magazine 21 50 6
NON-HEATSET WEB, Newspaper 28 58 10

Table: GATF-Measurements were made using a Status-T densitometer, and hue error was calculated using the Preucil Hue Error.


GRAYNESS

Grayness is a property of the ink that causes it to look dirty or dull taking away the saturated or brilliance of the ink. It does not necessarily change the color or hue. No color is perfect and every color will contain some amount of gray, the key is through measurement and control to keep your grayness value monitored. It indicates the purity or saturation of a color. If the readings increase during a press run, ink contamination may have occurred.

The most beneficial factor of the grayness function is to detect any problems of contamination of your inks. It also provides quality control in monitoring consistency of the printed ink during your press run.

The table below shows some typical Grayness values for three common printing conditions.

  GRAYNESS
  CYAN MAGENTA YELLOW
SHEET-FED, OFFSET 14 14 6
WEB-OFFSET, Magazine 21 18 51
NON-HEATSET WEB, Newspaper 42 34 25

Table: GATF-Measurements were made using a Status-T densitometer, grayness was calculated using the Preucil Grayness Formula.


SATURATION

Saturation refers to the purity of a color. The more saturated a color the deeper it becomes, until a point of too much saturation. As a color is de-saturated, it moves from its purest form, increasing in grayness. A totally desaturated color appears neutral, or void of color altogether. A color with more gray is considered less saturated, while a bright color, one with very little gray in it, is considered highly saturated.

By using the saturation function on your densitometer, this allows you to keep your saturation level monitored throughout your press run.


CAST

Color Cast - the overall tendency towards one color in a color image. A color cast is whenever a color is not the right color. A uniform or even color cast is when the entire image has the same cast, i.e. the entire image has turned yellowish with poor printing and caused the colors to be wrong. Cast is measured to evaluate the color of the paper.


BRIGHTNESS

Brightness refers to the overall "lightness" or "darkness" of a hue. Its possible, for example, to examine two colors with identical hues and saturation levels, but differing brightness levels. Colors like black have a low brightness. The brightness function on your densitometer will indicate the amount of brightness on the paper.


DOT ANALYSIS

Dot analysis allows the user to record the dot gain characteristics of a printing system. The dot gain measurements are recorded on a 10% graduated scale. A corresponding graph is generated to show a visual representation. The data can be saved on a file for future reference.


AUTO FUNCTION

The auto function allows the user to measure density, dot gain and ink trap interchangeably. In this mode, the instrument can determine if the measured target is a solid, half tone or overprint. The corresponding function will be displayed. This mode is useful when the operator uses these three functions frequently.


Product Specifications

Measuring Geometry: 0°/45° (ANSI PH2.17, ISO 5/4, DIN 16536)
Filter Response Status: Status T, Status E, Status A
Repeatability: ±0.01D (1%)
Measuring Range: Density 0.00D - 2.50D, Dot Area 0% - 100%
Accuracy: ±0.02D (2%)
Light Source: Halogen Lamp, Approx. 2856°K
Aperture Diameter: 3.0mm (1.7mm optional)
Detector: GaAsP Photodiode
Display: 128 x 64 Dot Graphic LCD
Power Supply: Ni-Cad (4.8V), 800mAh
Recharge Time: Approximately 1.5 hours
Measurements per Charge: Approximately 4,000 (Internal Testing)
Warm Up Time: None
Measuring Time: Approximately 1 second
Operating Temp. Range: 41°F ~ 104°F (5°C ~ 40°C)
Polarization Filter: (Optional)
Security User Code: (Optional)
Dimensions: 2 3/4" W x 2" H x 8 1/4" L (72mm x 50mm x 210mm)
Weight: 1.2 lbs. (with batteries) (530 g)
Computer Output: Configurable RS-232C Serial Interface

Comes standard with a US 2-Pin flat plug.
Also available with a Euro 2-pin round plug or a British 3-pin plug.
Email for information and a quote.

If ordering a NiCd Battery Pack please include the below information to verify correct battery is being ordered.

  1. Email serial number of existing densitometer, or
  2. Email part number from existing battery pack, or if it shows R1, R2, or R3, or
  3. Email a picture of existing battery connector
  • Models: EQP-R730-TNXU, EQP-R730-TSNU, EQP-R730-TNPU, EQP-R730-ENXU, EQP-R730-ESNU, EQP-R730-ENPU, EQP-SFTW-008, EQP-BATT-005, EQP-BATT-003 & EQP-BATT-007
  • Manufactured by: Ihara/Japan

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Ihara Densitometers














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