Not all scanned pictures turn out perfect. Sometimes they end up grainy. So how do you fix it?
Using your Photo editing software and if your software has these options you can:
If only part of the picture is grainy, select just that portion to work with. If you are working with the whole picture, skip this and go on.
Go the your menu options and select the tool that will allow you to Feather. Enter a value that will adjust the picture, which is usually 8 pixels.
Select the Filter menu option and go to Noise. Reduce the Noise.
Adjust the levels, the strength, the sharpness. Play with the levels to adjust the picture to your likeness. Click Ok to save the changes.
Zoom in on any of the areas that are still grainy. Select the smudge tool from the tool bar. Set the smudge value to about 70 %. With your mouse drag over the area. Hold the left mouse button down while smudging the area.
Or try using the blend tool, which can be found with the Blur tool.
Select the Filter menu - go to Blur - Smart Blur. Adjust the sliders until you are satisfied. Click OK to save the changes.
This is just one option, if you have a different way of fixing grainy pictures, share with us.