John Doe wrote:
Duplicate the layer, put it above and then change the blending mode to Multiply. You can then duplicate this layer several more times to make it darker if you need to.
Robert
Yup, thatta work. If the letters start to bleed a bit much you may use a curves layer on top of that to finetune the results.
I tend to have a slight favour for (too) dark scans in such cases. Rather have all the text and remove some darkened white paper bits afterwards than the other way around.
If you want a full white backrgound with text, you may wanna dupe the original layer, check the color channels and pick one that has the highest contrast. copy that to a new channel, and add a curves layer. push the black and whitepoints inward (black from left to right, and white vv) to leave a stark b/w contrasty image.
Check the RGB "channel" again and go back to layers. Add a new white layer under the layer you are going to work on. (Ctrl-click on new layer icon adds a layer below) Go back to the working layer and add a layer mask. Load the alpha channel as a selection and click on the layer mask. Then painting in black you'll see the white bits turn to a full white. Work your way across the entire document. Correct mistakes by using white as a brush or using the eraser (make sure colours are set to default b/w (d on the keyb, x will swap them around))
if you rather have some realistic looking parchment as a background, load some nice papery picture you have laying about and put that just below the masked layer. Presto!
HTH
Pjotr