A-A-2767
4.4 Tests.
4.4.1 Stability of ink.
4.4.1.1 Original stability. Examine the sample of ink in its original container for precipitation by inserting a glass rod. If present, invert bottle and shake vigorously for one minute. Examine again for sediment and coagulation. Place a few drops of ink between glass plates and rub plates together and examine for granulation. (See 6.3.)
4.4.1.2 Stability to temperature changes. Samples of ink in their original closed containers shall be exposed, one container to both of the temperature condition for the applicable type as follows:
Type I:
(a) At 51o +/0 2o C. for four hours.
(b) At 0o +/- 2o C. for four hours.
Type II:
(a) At 71o +/- 2o C. for four hours.
(b) At -53o +/- 2o C. for three days.
The inks after exposure to the above specified temperatures shall be examined for coagulation, granulation, tested as specified in 4.4.1.1.
4.4.2 Performance. The performance tests shall be made with clean and properly sharpened drawing pens and the ink shall be observed for drying out in the pens, during the tests.
4.4.2.1 Ink flow.
4.4.2.1.1 Test 1. Set a drawing pen at an opening of 76 microns +/- 25 microns (0.003 +f- 0.001 inches) and fill it with sufficient ink to draw at least five lines, each 18 cm long. The lines shall be drawn on drawing paper. The ink shall be considered unsatisfactory if it is not possible to draw five clean, sharp, unbroken lines of uniform width.
4.4.2.1.2 Test 2. Set a detail drawing pen with at, opening of 635 microns +/- 25 microns (0.025 +/- 0.001 inches) and draw 10 lines 5 cm long, on both plain paper. After the lines are allowed to dry, lines of the same width and length shall be drawn at right-angles across each of the sets previously drawn. The interjecting lines shall be free from distortion or blots.
4.4.2.2 Penetration. A sample of the markings prepared in 4.4.2.1.2 shall be rubbed with an eraser of the “Van Dyke” 6500 type or equal. The ink markings shall be completely erasable.
4.4.2.3 Color, opacity, and gloss. Draw to lines, 30 cm long on plain paper. After the lines are dry, apply another coat on the second line with the second ink. Examine the middle portion of each line for intensity of color (blackness), opacity, and degree of gloss.
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