Removing scanned paper grain

Perfect_Syntax · Posted: Thu Oct 21, 2004 10:26 am Post subject: Removing scanned paper grain

Does anyone know how to do this?

I scan a white sheet of standard photocopy paper and there's paper grain showing up in blotches on the scanned image! What's the best way to remove this grain stuff without affecting scanned artwork? Using curves to increase the brightness is simply too crude.

BryanDowning · Posted: Thu Oct 21, 2004 3:57 pm Post subject:

What did you scan? If there's a lot of contrast between your art/text/whatever you scanned, then you could use the magic erase tool with Contiguous unchecked.

JacobChalkley · Posted: Sat Oct 23, 2004 12:39 pm Post subject:

I learned this a while ago, so my memory is not the best.

Try going to Filter> Noise> Median and keep the radius low (around 1)
then go to Filter>Sharpen>Unmask and play with the settings.

You can also substitute a Gaussian Blur instead of the Median.

Other than, try playing with some of your scanner settings. Sometimes turning what you scan to an angle helps. That's assuming that what you're scanning doesn't take up your whole scanner bed.

teddc · Posted: Sun Oct 24, 2004 4:10 am Post subject:

I remember reading somewhere if you scan the right way up then rotate the pic 180 deg and scan again.
Then copy these two images onto two differnt layers, rotate 180deg again and align one of the images then blend (I forget which mode).

The reason why the grain appears is the way the light in the scanner reflects from this grain. By rotating as above one should cancel out the other.

Ted

teddc · Posted: Sun Oct 24, 2004 7:37 pm Post subject:

Try this link

http://www.retouchpro.com/forums/showpost.php?p=48529&postcount=2

thehermit · Posted: Mon Oct 25, 2004 4:22 am Post subject:

How long have you been visiting RetouchPro tredc? It's one of my haunts from old, Doug and the gang have some scary knowledge of retouching and associated between them.

teddc · Posted: Mon Oct 25, 2004 3:41 pm Post subject:

thehermit, well not all that long. reminds me of my early days when I was doing restoration as a business. whew!! no money in that

great site though!

ted

Perfect_Syntax · Posted: Fri Nov 05, 2004 7:26 am Post subject:

Thanks, guys! I tried the different things including the rotation method, which seems to eliminate the worst of the grains.

The problem with paper grain in my case is that it interferes with a light grey marker I use for sketching. The grain that appears on the scanned image has a very similar color to the marker. That's why it's difficult to use curves to eliminate the grain, because it also takes away some of the marker lines. of course, if I only used a black pen, it would be no problem to use curves.

Scanning the artwork twice at 180 deg rotations is time consuming, as well as using Neat Image (which gives by far the best results). So I've come up with a recipe which works satisfactory (for me, atleast). It compromises the grey marker, whic will appear more washed out, but that's ok. Actually that's better, because it eliminates the grain texture in the marker lines themselves.

For sketches with

-letraset promarker cool grey 2
-black nylon point 1 mm

1. scan artwork (which is on standard photocopy paper) at 300 dpi color.
2. select color range black with fuzziness 200.
3. edit -> fill with black. do this twice. (to make the black lines stronger)
4. deselect & repeat step 2. select inverse.
5. noise -> median with radius 6. deselct. (to eliminate the grain speckles)
6. curves with input 208, output 224. (to eliminate the paper color)

photorelive · Posted: Tue Apr 20, 2010 8:57 am Post subject:

easily and in seconds .. noise ware filter .. made for grains and old papers clells Birthday Big Grin

thehermit · Posted: Tue Apr 20, 2010 9:40 am Post subject:

Fast Fournier Transform Plugin, for a repeating pattern.

http://retouchpro.com/tutorials/?m=show&id=185

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