The Exchange Test Method

LABORATORY TEST METHOD NO. H-15: OPACITY OF PLASTIC/PAPER PRODUCTS

Issue Date: 30 Apr 1993

Revision Date:09/30/2011

  1. PURPOSE:

    To determine the opaqueness/opacity or "see through" characteristics of plastic sheeting/films or paper products.
  2. PRINCIPLE:

    Photo-volt meter is used to measure light reflectance of the item with a white backing and black backing to differentiate the "See through" characteristics.  NOTE: The reflectance of plastic/paper is higher when combined with a white backing than when combined with a black backing because, in the former case, light transmitted through the imperfectly opaque material is largely reflected by the white backing and a portion of the light, thus reflected, is transmitted through the material a second time.
  3. APPARATUS AND MATERIALS:

  4. PROCEDURE:

  5. EVALUATION:

  6. 6. REPORT

    Report the opacity in percent as an average of at least five readings.