4th December 2003, 01:18 PM
Creating a clean image from a scanned article
I'm doing up a article archive for my company and stores scans for newspapers, magazines etc..
I've come up with a work flow.. the tricky part is getting rid of the 'dirt' using Noise removal techniques without degrading text quality too much.
* Scan at 300dpi (at least 2x more then the size you want to keep)
If you have to save, use TIF, else JPG-Hi (in size constraints)
[Note: Even if you just need to view on screen later, it's important to scan high and size down in Photoshop]
* Ctrl-L: Levels (Before Crop & Straighten)
Use White eyedropper to point to 'dirt'
& Black eyedropper to point to black text
Keep toggling between these 2 until most of the dirt is out and text is still distinct.
* Crop & Staighten
Do this in 1 step
[Tip: Use a reference line as guide to straighten]
* Select Area to clean
Select All first (Alt-Lasso to deselect sensitive areas)
* Filter.Median 1px
* Manually Choose Blocks to fill with white
[Tip: First Ctrl-A to select all, and use Alt-Select to deselect non-white areas
Set White as foreground colour (D-X)
Use Alt-Backspace to fill with foreground colour
Manually select areas within text that still has stray dots, use Shift Select
Fill again with white with Alt-BackSpace]
* Resize down to actual size
* Save for Web (GIF, Selective Colours)
[Tip: Keep dropping the colours down, 256, 128, 64 etc and see the file size vs quality
you can even go furthur by looking at each colour and selectively lock colour or throw away colour in the colour palette]
4th December 2003, 01:57 PM
Filling blocks with white sounds time consuming.
What I do is scan with a piece of black paper behind the page so that the reverse doesn't show thru in the scan. White eyedropper on the page and black on text. Dust and dirt removal as per touching up photos.
Descreen if you have the option but introduces some softness. Apparently you can can remove moire by scanning slanted then crop and straighten, but never tried it.
5th December 2003, 05:35 AM
Yup.. a little more time consuming but that extra step just to be sure stray dots outside the text area are removed. Actually just 4 blocks..
Ctrl-A to select all
Alt-Deselect Newspaper heading
Alt-Deselect Text block
Can be done in 5-10secs if you're a seasoned PS user.