.isotope,
.isotope .isotope-item {
  /* change duration value to whatever you like */
  -webkit-transition-duration: 0.8s;
     -moz-transition-duration: 0.8s;
      -ms-transition-duration: 0.8s;
       -o-transition-duration: 0.8s;
          transition-duration: 0.8s;
}
.isotope {
  -webkit-transition-property: height, width;
     -moz-transition-property: height, width;
      -ms-transition-property: height, width;
       -o-transition-property: height, width;
          transition-property: height, width;
}
.isotope .isotope-item {
  -webkit-transition-property: -webkit-transform, opacity;
     -moz-transition-property:    -moz-transform, opacity;
      -ms-transition-property:     -ms-transform, opacity;
       -o-transition-property:         top, left, opacity;
          transition-property:         transform, opacity;
} 
  
    View source  
  - .isotope,
 - .isotope .isotope-item {
 -   /* change duration value to whatever you like */
 -   -webkit-transition-duration: 0.8s;
 -      -moz-transition-duration: 0.8s;
 -       -ms-transition-duration: 0.8s;
 -        -o-transition-duration: 0.8s;
 -           transition-duration: 0.8s;
 - }
 - .isotope {
 -   -webkit-transition-property: height, width;
 -      -moz-transition-property: height, width;
 -       -ms-transition-property: height, width;
 -        -o-transition-property: height, width;
 -           transition-property: height, width;
 - }
 - 
 - .isotope .isotope-item {
 -   -webkit-transition-property: -webkit-transform, opacity;
 -      -moz-transition-property:    -moz-transform, opacity;
 -       -ms-transition-property:     -ms-transform, opacity;
 -        -o-transition-property:         top, left, opacity;
 -           transition-property:         transform, opacity;
 - }