In response to no stop or utilitizing the stop too quickly in RA4 allows. . . for dull orange blotches wherever the developer didn't get fully stopped. If not using stop be sure to rinse well for at least a minute. I "remember" this because just last week, I got in a real hurry and rushed the stop. Haven't done that in a while, but there is was an orange almost fog through the middle of the print where apparently I didn't immerse as fully as I had thought.