Whose curve did you download from the web? If you expect to use someone else's curve with success a number of conditions must be met. You should have the same printer, with the same print setting, and the way you work your process should be almost identical to those of the person who supplied the curve. For example, my kallitype curve would be of absolutely no use to you unless you also make your negatives with an Epson 2200, use the same contrast controls I use with kallitype, and use the same paper.
Some of the generic curves may work reasonably well but for best results you need to tailor the curve to your printer and process.
Originally Posted by Mark Fisher