The best way to get legitimate access to Umineko manga is to purchase or borrow from a library. Trying to find raw scans elsewhere is not recommended as it's often against the law and doesn't support the creators.
You might be able to find them on some less reputable websites, but it's illegal and not recommended. It's better to support the creators by reading officially licensed versions.
First off, you should have the right tools. Then, pay attention to details like cleaning up any noise or artifacts. Also, make sure the contrast and brightness are balanced to bring out the best in the scans. It takes some practice and patience.
It's had a huge negative impact. Pirating cuts into the profits of manga creators and publishers, making it harder for them to keep creating and distributing new content.
It's had a huge negative impact. Piracy steals potential revenue from creators and publishers, which can lead to less investment in new manga projects.