Quality levels for labels

2.1 Prestige quality

Printed labels, embossed, laminated, gold-stamped, multi-color or process printing in solids or halftones. Printed on the entire surface, die-cut or precision trimmed, suitable for manual or mechanical applications.

2.2 Informational quality

Printed labels, multi-color or process printing of solids, halftones or lines. Printing on the entire surface, die-out or precision trimmed, suitable for manual or mechanical applications.

2.3 Utility quality

Printed labels, die-cut or precision trimmed, suitable for manual or mechanical applications.

3.1 Folding

Mispositioning of a fold is recorded as the displacement of the actual fold from specified positioning, plus skew displacement (if any).

3.2 Rub-Resistance of printed image

A representative sample of the print is placed on a Sutherland rub-tester (or equivalent instrument) and given 25 rubs at a pressure of 1 psi against an unmarked sample of stock similar to that on which the print is made. Density readings are then made on the rub-off smear, having pre-zeroed the densitometer on an unmarked sample of the rubbing stock. An average density is calculated for the rub-off smear.

3.3 Extraneous marks

Lines, spots, smears or other extraneous (background) markings are assessed visually. Generalized extraneous marking, covering a large area (e.g. scumming, tinting) are assessed in terms of average reflection density of the affected area.

3.4 Register

Misregister is recorded as the linear displacement of any character in any direction, relative to the other characters.

3.5 Trim size

Long or short trim is recorded as the difference between specified and actual size of the trimmed work. A plus sign may be used to denote oversize work, and a minus sign for undersize.

3.6 Character gain

The gain of any part of a printed character is measured and expressed as a percentage of the same character on the original copy. The variation of change is the difference between the maximum and minimum percentage values found on the related area of printing.

3.7 Plugging

This normally occurs with characters having an enclosed area such as the letters a, e and o. The degree of plugging is measured with a measuring reticle and expressed as a percentage of the open area that has been filled in.

3.8 Doubling or slurring

The secondary or ghost image adjacent to the primary character is measured with a magnifier having a measuring reticle and is expressed as a percentage of the primary image.

3.9 Voids

A representative area of printed type 2.5 cm wide x 2.5 cm deep (1 in. x 1 in.) is selected. The total number of voids within this area is counted and weighted according to the size of the void as follows:

Multiply each void by its corresponding weighting factor and then sum the total count. The total void count as well as the average void count calculated from randomly chosen areas throughout the job should not exceed the specifications.

3.10 Moiré

A representative area of a color reproduction is selected. Where two or more screen images are superimposed, angle settings are checked using a screen angle gauge. A 30-degree displacement of each strong color is desired.

The common set of screen angles used is:

• 45 degrees — Black Printer Angle
• 75 degrees — Magenta Printer Angle
• 90 degrees — Yellow Printer Angle
• 105 degrees — Cyan Printer Angle

3.11 Trapping

In order to measure trapping, the exact order of ink lay down must be known and should be marked on the press sheet.

1. After choosing the appropriate overprint patch, select the densitometer filter for measuring the second color down
2. Measure the density of the overprint patch
3. Measure the densities of the solid patches of each of the two colors used In the overprint
4. From the density of the overprint patch, subtract the density of the solid of the first color down
5. Express the value found in the above step (d) as a percentage of the solid density of the second color down

This percentage must not be less than the specified value.

Example: Magenta Overprinted on Yellow

1. Densitometer set to measure magenta
2. Magenta/yellow overprint density = A
3. Magenta solid density = B, yellow solid density = C
4. Magenta/yellow density minus yellow solid density = D; 1.17 - 0.15 = 1.02
5. (1) A - C = D
   (2) D/B = % Trapping

3.12 Color match

This test procedure is for use only with solid spot color and not for tints or process color. Measurements are made using a CIE response, three-filter colorimeters with a D65 illuminate. Measurements are made on samples of the printed solid and on an approved color swatch. The measured results are expressed in CIE LAB coordinates; L^*, a^*, b^*.

NOTE: While the printer may not have the required equipment to make these measurements, it is still possible to achieve an acceptable color match with the aid of a color reflection densitometer.

3.13 Color density (densitometry)

The following procedures are considered to be the methods for measurement of ink density on paper and are the only ones that should be applied in the evaluation of any printed material. All quality appraisals performed should be based upon density readings on dry ink. The surface on which the press sheet is placed for density reading should be covered with several thicknesses of unprinted, white paper. The color control bars must not be backed up with any printed image. Only ink patches that are free from defects such as chalking, snow-flaking or dirt are considered acceptable for evaluation.

Since the colors used to designate the filter settings on densitometers are not consistent, care must be taken that the proper filter is used for each process color.

The densitometer will be calibrated on each filter setting using a calibration plaque, in good condition and by a method recommended by the densitometer manufacturer.

^* Where other than Process color densities are to be determined, the reading from the filter giving the highest density reading is determined.

3.14 Color tints

Their corresponding densities control the degree of dot gain or loss in the tint patches. The densities on the tint patches of the control bars should not vary from those on the approved proof or "OK" sheet tint densities by more than the specified tolerances.

For example: With a 40% tint of ordinary process color ink, a density variation of ±0.03 is approximately equal to a dot area change of ±3% and a density variation of ±0.05 is approximately equal to ±6%.