Just bought some better spark plugs and upon changing them have noticed that they are ranging from dark to light in sequence

#1 being the darkest
#4 being lightest





is it running lean? im still running it in, will be getting set up once running in is complete

what would cause this and what can i do to alleviate the problem if it is for the time being? will i still be ok to use it like this til i get it set up in a week or 2?