here is a little script, that i hope, will help you :

• start with a 600dpi scan (don't forget to put a black paper behind the page , to make disappear the caracter of the other side of the page)
• zoom where you can see the white paper
• lauch the script
• on the histogram windows, select white pen, then click on the withe paper try to make disappar this white paper
• in the end of the script, go back to histogram, to put the black on the limit the level begin (don't stick too much, or you'll contrast too much the scan)

this script let see somtime a little too much the point. anyway, it's relly close to the real resolution of colour print magasin, witch is near 260 DPI.

this script embed a sRGB profile on the picture in the end. KEEP IT on SAVE !

Don't forget that for single coulour print, the real resolution is a lot higher ! it's the use of this very high resolution, to print in colour, and, create coulour that doesn't exist in the ink

here is a script that will help you to enhance photo

it'll split the pic in several layers

• the 3 first layers are “level layers” black, white, and medium. It use the curve selection, that give a lot more precision than “level”. the others are classic witch are usefull somtime
• the last one is a “enhance detail” layer, that you can enable or disable if you think you need it
• and.. the 3 shot are.
  1. the original pic
  2. the pic color adjusted with CTRL-ALT-B
  3. the pic non color adjusted
• an sRGB profile is embedded in the end of the script

then.. you can start enhance your pic, as now you've got a lot of layer to modify

downloads the scripts here