📘 In the present work, the isothermal decay of additively colored micro crystalline powders of various sizes and whiskers of potassium halides was studied. The decay of colors centers in powders and in whiskers of approximately same diameter was compared to get more information about interactions with dislocations. Also it will be interesting to see the effect of reversing the coloration crushing sequence in the manifestation of the interaction between color centers and dislocations.So the decay in additively colored powders was compared with decay in the powders of same size obtained by crushing the additively colored crystal's.