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Trouble cleaning a signature

Posted on 2013-11-02
Medium Priority
Last Modified: 2013-11-20
Here is my result http://screencast.com/t/ON5PzXQi5d after following this handy video http://www.youtube.com/watch?v=efAOsvfi4sU.

What else might I be able to try?
Question by:frugalmule
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LVL 33

Expert Comment

by:Paul Sauvé
ID: 39619447
Which graphics app are you using??? It seems to me that it is GIMP... Please confirm.
LVL 33

Expert Comment

by:Paul Sauvé
ID: 39619455
First of all, Select menu -> None and now you should be able to remove all the little black dots using the easer tool.

Now, select the black color using the Select Color Tool rather than the Magic wand (just to the right of the wand in the toolbox).

Now, use the Edit menu -> Stroke selection and set to 1 or 2 pixels. This will make the line just a bit heavier... Works much better than going over with the paint brush.

Make several layers of the original and play areoud a bit. You could try Stroke with a paint tool as well. See what gives you the best results.

Expert Comment

by:Christopher Jay Wolff
ID: 39619470
Hi guys.

To save future edit time, you may want to find the source of your little black dots. Is it coming from the paper you wrote your signature on, or dirty glass on your scanner, etc.

Eraser tool works on dots as paulsauve says, yet I often prefer the lasso tool, one button to the left of fuzzy select tool.  Looks like a lasso.  You can draw a line around all the dots enclosing them in a free-form shape and hit delete.

I could not get decent results with Select Color Tool and Stroke Selection.  Maybe I'm misunderstanding how.  I usually use the method described in youtube video provided by frugalmule.  For smoother lines you may want to try different pens.  There isn't anything about a Sharpie that has ever given me better results.  Could even like a medium ballpoint.  It may have less bleeding into paper.

Also for smoother lines, you also can adjust your threshold, anti-aliasing and feathering options under the fuzzy select tool.  Often you want to do anti-aliasing and feathering on the same color your signature will have as a background on the final media.  Probably not worth the hassle here, but if you adjust your threshold down a couple notches, your fuzzy select may give you better results in the first click, including possibly eliminating your dot problem.  I tried a fuzzy select with threshold at 15 and 16, it looked nicer at about 7.
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Author Comment

ID: 39619473
It's gimp.  Still working at it, not much luck

Expert Comment

by:Christopher Jay Wolff
ID: 39619477
Do you mean the eraser tool or any other selection tool won't get rid of your dots?

Author Comment

ID: 39619479
any selection tool.

dots are very close and evident

I just don't know how to use the tools well

Expert Comment

by:Christopher Jay Wolff
ID: 39619496
Do you see the lasso button?  Looks like rope lasso.

Click on it and make sure the button appears pushed or selected.  On my mac, I have to click on the GIMP window to make it active first before I can click on lasso.  Then I click lasso button.  See attached.

Or same procedure to click on eraser button.  See attached.

Then I have to click on my image editing window to make it active.  Then I can click on where I want in the image to begin deleting dots.

Expert Comment

by:Christopher Jay Wolff
ID: 39619519
I should be more clear.  You can select the dots with a selection tool like the lasso, and then delete them.  Then the delete key will delete what has been selected.  The selection area is indicated by the "marching ants."


You are free to not use a selection tool to select the dots.   Simply use the eraser tool to erase them, as paulsuave suggested.  Again though, the eraser will either erase in a selected area within "marching ants" or, you can go to the Select pull down menu of your image window, choose None, and the eraser will erase anything it goes over.  If you use the eraser tool without a selection area of "marching ants", just be sure not to run into any part of your signature by accident.  That is why I often prefer the "select, then edit" process.

Is the following true?
Your transparent area is what is selected, therefore the eraser tool cannot erase the dots because they are not yet selected?  It looks about the same if you invert the selection to only include what is black, namely your sig and the dots.  If so, do CNTL+I to invert the selection.  Then your black signature and the dots are selected.  Be careful not to erase any part of your signature in this case.

That is why I usually remove all selections for a new edit.  Then I would select my dots only, and delete or erase them.
LVL 70

Expert Comment

ID: 39619643
When you got to the part where you had deleted the background with the fuzzy selection tool don't overlay it with the paintbrush do it later, just a suggestion :)
Regarding when it has the dotted lines around that just means it's still active with that tool, deselect it so that you just have the transparent,
You could save it then and reload it on to a white background then using the clone brush
Or just click on the clone tool
select a white clean spot and wipe out those bad bits.
 a quick video how to
and another
With clone and patch tool Gimp
How to Use the Clone Tool in Gimp with pictures
and another just with pictures
Great fun once you master it can do wonders
LVL 33

Accepted Solution

Paul Sauvé earned 2000 total points
ID: 39620057
Here is my workflow to accomplish this:

step 1 - scan image of signature

step 2 - crop the signature AND duplicate this layer (just in case you mess up)  - if you like you can duplicate the working layer after eash step. I always make the lower layers invisible to see only the layer I'm working on....

Crop - 1Crop - 2

step 3 - add alpha channel (if there is none)


step 4 - use the Select by Color Tool to select and erase background


step 5 - clean up the extraneous spots with the Eraser Tool


step 6 - use the Select by Color Tool to select the background

step 7 - invert this selection


step 8 - use Bucket Fill Tool (with Black foreground) to fill selection

BucketBEFORE (received faxed document and scanned):AvantAFTER:Après

Author Comment

ID: 39620067
Paul, thank you. That looks the most straight fwd.will try

Author Closing Comment

ID: 39635177
This is a really option for 'cleaning' a signature using Gimp.  Thank you!
LVL 33

Expert Comment

by:Paul Sauvé
ID: 39662971
Of course, since your initial question: ...Here is my result http://screencast.com/t/ON5PzXQi5d  shows that you are using the GIMP!

You're welcome and thanks!

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