What Is Haze?
Haze measurement is the evaluation in which the diffuse component of light transmitted in a transparent material is measured as the ratio of the total transmittance (ASTM D1003) or the diffuse component of reflection in a glossy coating (ASTM D4039).
Purpose of Haze
The aim is to quantitatively inspect the quality of transparency or surface clarity in high gloss coatings.
Which Products Is Haze Applied To?
- Transparent plastic sheets and films
- Automotive headlight lenses
- High gloss paint systems
- Packaging films
In Which Sectors Is Haze Used?
Standards Related to Haze
- ASTM D1003
- ISO 13468
- ASTM D4039
- ASTM E430 (surface clarity)
Haze Conditions
- permeability haze
- Total and diffuse permeability are measured; The rate is given as a percentage
- reflection haze
- Difference between 20° brightness and diffuse reflection at close angle
- Calibration
- With certified haze standards
- Surface
- Must be clean, free of scratches and dust
Equipment for Haze
- Haze meter (sphere geometry)
- reflection haze meter
- Certified haze standards
- Cleanroom-like sample preparation area
Sample Requirements for Haze
- The sample surface must be free of dust and fingerprints.
- Sample thickness must be reported
- Film samples must be stretched without wrinkles
- Measurement points must be representative
Duration of Haze
Typically 1 day.
Haze Procedure
- 1The device is calibrated with certified standards.
- 2The sample is cleaned.
- 3Total and dispersed components are measured.
- 4Haze percentage is calculated.
- 5Iterates over a defined number of points.
- 6The result is reported with thickness.
Haze Acceptance Criteria
The acceptance criterion is the maximum haze percentage given in the specification.
Evaluation of Results
Dust and scratches on the surface increase the haze value; Cleaning before measurement determines the result. Transmittance haze and reflection haze are different quantities and cannot be compared. Haze value depends on thickness, thickness should be reported.
Haze Report
- Standard and method applied
- Specimen thickness
- Calibration records
- Total/dispersed ingredients and haze percentage
- Surface preparation
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- Product and OEM specifications
Paint and Coating Testing — What Does This Testing Field Cover?
The section below describes the field that the Haze test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Paint and coating testing measures the adhesion of a coating to the surface, its mechanical durability and its resistance to environmental effects. Because a coating is a thin layer, the results depend both on the material and on the QUALITY OF APPLICATION; the same paint gives an entirely different result over a different surface preparation.
This dual dependence is the most important knowledge in the field. A coating failure usually arises not from the paint itself but from the surface preparation: oil residue, insufficient roughening, an oxide layer or moisture. Coating tests therefore assess not only the product but also the process, and the results are used for process control.
COATING THICKNESS is a recurring variable in the field. Many durability results relate directly to thickness; a thin area becomes the starting point of corrosion. Thickness measurement is therefore reported routinely alongside the other tests and is usually taken at several points — thickness falls at edges and corners, especially on complex geometries.
Three approaches are used on the adhesion side, each giving different information. The tape test is fast and suitable for field use but is a coarse scale. The cross-cut test shows behaviour at the intersections of layers. The pull-off method produces a numerical strength value and is the most suitable for comparison.
On the mechanical side, flexibility (mandrel bending), impact resistance, hardness, abrasion and stone chip resistance are measured. Stone chipping has a special place in automotive: gravel striking the coating under real road conditions is simulated, and the result is assessed according to whether the coating continues to protect the base metal.
On the appearance side, gloss and colour difference are monitored NUMERICALLY. Colour is assessed with a colour measuring instrument rather than by eye and the colour difference is expressed as a number; this makes it possible to compare different lots and different suppliers.
On the durability side, accelerated ageing (xenon arc, fluorescent UV), humidity, condensation and salt spray are applied. The result is assessed with scales for blistering, rusting, creep from a scribe and loss of adhesion; these scales are defined in separate standards and the report must state which was used.
In industrial processes such as powder coating and electrophoretic coating, the curing cycle (temperature and time) is what determines the result. An under-cured coating looks good but has poor chemical resistance and adhesion; oven profile measurement is therefore part of coating quality control.
Method groups in this field
Thickness
Dry film thickness by magnetic and non-magnetic methods; multi-point measurement and assessment of the distribution.
Adhesion
Tape test, cross-cut test and pull-off adhesion strength.
Mechanical strength
Mandrel bend flexibility, rapid deformation (impact), pencil and scratch hardness, Taber abrasion, stone chipping.
Appearance
Gloss measurement, colour difference calculation, orange peel and surface defect assessment.
Environmental durability
Salt spray, humidity, condensation, xenon arc and fluorescent UV ageing, chemical and stain resistance.
Assessment scales
Scales for blistering, degree of rusting, creep from a scribe and loss of adhesion.
Commonly confused in this field
- A coating result depends on the surface preparation; even if the paint itself is good, a poor preparation gives a poor result.
- A durability result without a reported thickness cannot be compared.
- The tape test is a coarse scale; numerical comparison requires the pull-off method.
- Colour cannot be assessed by eye; numerical colour difference measurement is required.
- An ageing result without a stated assessment scale cannot be interpreted.
- If the curing cycle is incomplete the coating looks good but its durability is poor; the oven profile is part of quality control.
Which decisions these results support
- Paint system approval and supplier selection
- Process control of the paint line and lot acceptance
- Supporting outdoor and automotive durability claims
- Detecting defects arising from surface preparation
- Monitoring colour and gloss consistency lot by lot
Related Tests
Frequently Asked Questions About Haze
According to which standard is Haze made?
Haze is executed in scope ASTM D1003, ISO 13468, ASTM D4039 and ASTM E430 (surface clarity). The limit values and acceptance criteria to be applied are defined in the product standard; The version valid for your product is confirmed in writing at the offer stage.
Which products does Haze apply to?
Mainly applied to Transparent plastic sheets and films, Automotive headlight lenses, High gloss paint systems and Packaging films. Whether your product is included in the scope is determined by examining its technical specifications and intended use.
Under what conditions is Haze done?
The determining parameters are: permeability haze — Total and diffuse permeability are measured; The rate is given as a percentage, reflection haze — Difference between 20° brightness and diffuse reflection at close angle and Calibration — With certified haze standards. The full terms are in the "Test Conditions" section on the page and vary depending on the product standard.
What kind of sample is needed for Haze?
The sample surface must be free of dust and fingerprints., Sample thickness must be reported and Film samples must be stretched without wrinkles. The number of samples is determined according to the product standard and the scope to be reported.
How long does Haze take?
Typically 1 day. This duration belongs to the experiment itself; sample preparation, queuing and reporting are also evaluated. A realistic schedule for your product is given in the offer.
What is the Haze result called "appropriate"?
The acceptance criterion is the maximum haze percentage given in the specification.