u/ButterscotchDull7267

Just curious why they are recommending two developing times… one for 9 minutes and another for 9 minutes and 45 seconds. Is there a major difference developing for an extra 45 seconds? Is there more contrast? Thanks in advance for the help!

Finally set up my non-wet darkroom after realizing I cannot work out of my house/bathroom cus I have no room lol… so I rented a small artist studio… any tips on keeping the dust down? Thanks!