The duration for testing samples from dyes and pigments suppliers varies depending on the type and complexity of the tests. Here are some common tests and their typical time frames:

1. Particle Size Analysis
- Laser Diffraction: Usually takes less than a minute.
- Powder XRD Testing: Generally takes about 10 to 20 minutes, depending on the scanning speed.

2. Lightfastness Testing
- Xenon (Xe) Lamp Exposure Testing: Typically takes several days to weeks, depending on the test standard and requirements.
- UV Exposure Testing: Generally takes several days to weeks.
- Natural Weathering Exposure Testing: May take several months to over a year.

3. Solvent Resistance Testing
- According to the national standard GB/T 5211.5-2008, the testing process includes shaking, filtering, and colorimetry, usually taking several hours to complete.

4. Weathering Resistance Testing
- For weathering resistance testing of pigments in exterior building coatings, natural exposure testing may take several months to a year.

5. Other Tests
- For certification testing, such as the type test for rutile titanium dioxide pigment under the "Taishan Quality" certification, it should be completed within 15 working days after receiving the samples.
- For special color-changing material testing, including high and low-temperature, humidity resistance, and aging tests, it may take up to 180 days.

Summary
- Simple Tests (e.g., particle size analysis): Usually completed in a few minutes to a few hours.
- Complex Tests (e.g., weathering and lightfastness): May take several days to months, or even longer.
- Certification Tests: Depending on the specific standards and requirements, they may take several weeks to months.

In practice, it is advisable to clearly communicate the specific testing requirements and expected time frames with the dyes and pigments suppliers to reasonably plan production and procurement schedules.