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Quality Levels for Labels

Table of Contents

  1. Introduction
  2. Quality Level Categories
  3. Evaluation Methods
  4. Details Requirements

1. Introduction

Quality Levels for Labels was developed by  Public Works and Government Services Canada (PWGSC). The purpose is to establish a common base of principles, practices and understanding between Federal Government departments and suppliers in selecting the print quality level most appropriate for required labels.

This document is to be used in conjunction with the following PWGSC publications:

  • Quality Levels for Printing
  • Quality Levels for Color Reproduction
  • Quality Levels for Typesetting
  • Quality Levels for Forms

The label contractor must ensure that all quality requirements listed in the related quality levels publications are achieved in the final product.

Three levels of label production quality are defined in descending order: Prestige Quality, Informational Quality and Utility Quality. While quality control and final production specifications are detailed for each level, this document does not restrict or control any manufacturing process or processes but sets quality guidelines that must be achieved in the manufacturing of label products. It is the supplier's total responsibility to control processes to achieve the quality requirements regardless of the type of manufacturing processes used. The supplier must supply labels conforming to good workmanship, using good trade practices and materials specified, resulting with consistency throughout the entire job.

Questions concerning a specific contract should be directed to the contracting officer named on the contract.

Please direct any comments or proposed revisions to:

Manager, Printing Procurement Division
Constitution Square
360 Albert St., 12th Floor
Ottawa, Ontario, K1A 0S5, CANADA

2. Quality Level Categories

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. Evaluation Methods

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:

Size of Void Weighting
0.05 mm to 0.10 mm (0.002 to 0.004 in.) 1
greater than 0.10 mm (0.004 in.), but less than 0.15 mm (0.006 in.) 3
0.15 mm (0.006 in.) or greater* 10

*Any void that causes a character to be indistinguishable is unacceptable.

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.

Process Color Correct Densitometer Filter
Cyan Cyan Filter
Magenta Magenta Filter
Yellow Yellow Filter
Black Visual Filter

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%.

4. Details Requirements

Description Prestige Informational Utility
folds shall not be mispositioned by more than .40mm - (0.016 in.) .80 mm - (0.032 in.) .80 mm - (0.032 in.)
Image Rub-Resistance:

maximum acceptable density of rub-off

0.00 0.03 0.06
Extraneous Markings:
maximum acceptable background density difference 0.02 0.04 0.10
Register: misregister shall not exceed
-150 - line screen ±0.04 mm - (0.0016 in.) ±0.08 mm - (0.0032 in.) ±0.15 mm - (0.006 in.)
-133 - line screen ±0.05 mm - (0.002 in.) ±0.10 mm - (0.004 in.) ±0.15 mm - (0.006 in.)
Trim Size:
maximum acceptable variation from specified trim ±0.40 mm - (0.016 in.) ±0.80 mm - (0.032 in.) ±0.50 mm - (0.059 in.)
Characted Gain:
percentage of original character size maximum acceptable range 95%-105% 85%-115% 50%-150%
maximum acceptable variance 5% 10% 15%
Image Placement:
image displacement shall not exceed ±0.15 mm - (0.006 in.) ±0.40 mm - (0.016 in.) ±0.80 mm - (0.032 in.)
maximum percentage of plugging allowed 0% 10% 50%
Doubling or Slurring:
maximum percentage of doubling/slurring 0% 5% 25%
Type Voids (Broken Type)
maximum count on any label 2 5 50
maximum average count per 2.5 mm2 (inch 2) 1 3 5
displacement maximum of superimposed screen in either direction (degree) 0 5 10
must not be less than 75% 75% 75%
Colour Match (Single "Spot" Colour):
total colour (Delta E*) between specified and printed colour must not exceed 2 4 5
Colour Density (Single Colour Solids):
maximum density variation allowed ±0.05 ±0.10 ±0.30
Colour Density (Screen Tints, Approx. 40%):
maximum density variation allowed ±0.03 ±0.05 ±0.10