After I did some mistakes on partial scans of pool #1870, I'm thinking to upload underfiltered scans with a special tag: semi processed scan in the next time on those type of scans.
how about this way or is there another good way?

I'm not sure that is a good idea. The users will still download, and distribute, these scans. Probably better to stick them on FTP.

The main reason I said it is about color adjusting. color adjusting is better to be done by one person, especially the one who scanned it. but also I know colors can't be adjusted well before semi-filtered.

hm.. (´・ω・｀) then another option is upload semi-filtered scans onto FTP.