Image Touchups

Sometimes, the image you get from your scanner just isn't what you had originally planned. Perhaps you've drawn on paper that wasn't quite of the quality you wanted. Or maybe you just want to give the image an extra boost of clarity.

But you don't have Photoshop?

Not to fear, there are plenty of free alternatives that'll do what you need. In this tutorial, we will assume that you're using Paint.net, a free replacement for MS Paint. For those of you interested in doing more complex and interesting editing, or those of you not on Windows, you might try using The GIMP, available for Windows, MacOS, and Linux.

Once you have Paint.net installed, you'll be able to follow the tutorials below. Be aware that there are some differences between Paint.net, Photoshop and the GIMP, so the commands and menus may not be the same, however the same basic tools are found in all three. 

Contents

• Download Paint.net
• General Tips
• Touching up grayscale sketches or line-art
• Touching up colored art
• Removing blue lines from lined paper
• Cropping
• Replacing an image in Gallery
• Customizing Thumbnails

Download Paint.net

Paint.net is a free download which you can get at the official Paint.net website. Just go here to download Paint.net. Note that Paint.net comes in two different "flavors". If you don't have the .NET 2.0 framework installed (or you don't know if you do) use the second download link. Once you have downloaded the program, run it and the wizard will guide you through the installation process. Once it is installed, you'll be able to access it through the Start Menu under All Programs.

General Tips

• While working with your image, save it in a lossless format, such as PNG or the program's native image format. Saving it as JPEG/JPG while working will cause your image to lose quality each time you save.
• Once you are done working with your image, save it to the format you want. For most cases JPEG will do fine when set at "High" quality (Photoshop) or a quality level of about 90 or above (everything esle).  If you want to avoid artifacts that JPEG introduces, you can use PNG (if you have a lot of variation in color) or GIF (if you don't have as much variation). See also these guides on file formats: GIF, JPEG or PNG, Web Style Guide: Graphic File Formats.
• Unless you intend to print your image, there is generally no need to scan at a greater resolution than about 150 dpi.
• When scanning, be sure you have selected the right mode for the type of image you're scanning. Usually, you'll want to use Color Photo for hand-colored art, Grayscale for pencil sketches or anything with just shades of gray, or Black & White Line Art for inked line art. Experiment with your scanners settings to see which ones give you the best results for what you're scanning.

Touching up grayscale sketches or line-art

So, despite your best efforts, say that you end up with a scan like this:

You'll notice that there isn't much contrast between the light gray paper and the darker gray of the sketch, making it hard to "read" very well. This is actually a fairly easy fix.

1. If it isn't already in Grayscale mode, convert it to grayscale. In Paint.net, choose the Layers menu, navigate to the Adjustments submenu, then choose Black and White. In the future, I'll refer to menu commands like this in this abbreviated form: Layers > Adjustments > Black and White.
2. Now, open the Levels Adjustment tool (Layers > Adjustments > Levels...).
3. You'll be presented with a dialog box that looks something like this:
   
4. Adjust the input and output sliders (the small black triangles) until the image looks the way you want it to. The Input sliders change what color should be "white" and "black", while the Output sliders change the value of the lightest shades, midtones, and darkest shades. For this image, I used the following settings:
   
5. Done! Now there's much better contrast.
   

   Before:

   After:

If you are using Photoshop, you may want to see this tutorial on its Levels tool instead, as there are some slight differences in how it works in comparison to Paint.net.

Touching up Colored Art

The process for colored art is pretty similar to touching up grayscale images, except that you don't convert them to black and white. Let's say we have the following source image:

Not a bad scan, really, but the colors are a tad washed out. Again, the Levels tool to the rescue!

For this image, I used settings like these:

And here's the result:

Before:	After:

Not a huge difference, but the lines are slightly darker and the colors are more vivid. You can also try experimenting with the R G B checkboxes to adjust the levels of the primary colors at a time, though doing this effectively is beyond the scope of this tutorial. You can also experiment with the Curves tool (Layer > Adjustments > Curves) for a bit finer control. This is also beyond the scope of this tutorial, however, the curves tool in Paint.net, Photoshop and GIMP work very similarly. See: Using the Photoshop Curves Tool.

Removing blue lines from lined paper

So, you're doodling along, and you've come up with something pretty good... but you used lined paper, because you were at school or whatever, and now mixed in with your picture are all these lines.

Unfortunately, as of this writing, Paint.net doesn't have the ability to easily get rid of these lines. See this tutorial if you'd like to use Photoshop. You may be able to use that tutorial with your graphics program of choice. I have tried it myself with The GIMP and found that this method does not seem to work well there, though your results may be different.

Cropping

Cropping is a great way to add a bit of flair to an image, especially if there's a lot of whitespace around it. It can also help remove small defects around the edges of a scan and things like that.

Let's take this picture here (gray background added for illustrative purposes):

Cute little pic, but it's got a lot of white space and there's also a black line from the original scanning. First thing you may want to do is move any outlying elemets inside the area that you're going to crop. For instance, I'm going to move the signature closer to Mrs. Brisby. To do this, use one of the selection tools, like the Rectangle Select or Lasso Select tool. In this example I've used the selection tool to grab just the signature.

Now, switch to the Move Selected Pixels tool (sometimes just called the Move tool) and move it closer, like so:

You can fill in the checkerboard pattern with the Paint Bucket tool. Use [CTRL]+D to deselect the selected area, then choose the foreground color you want to use, then with the Paint Bucket tool, click inside the checkerboard area. If you're having trouble matching the fill color to the page, use the Color Picker tool (also called the Eyedropper tool) on the page background.

Now, go to the Rectangle select tool and choose the area of the picture you want to keep, like so:

As a final step, crop the image and save it. In Paint.net, use Image > Crop to Selection. Here's what the image looks like when cropped:

Replacing an image in Gallery

So, say you uploaded a file and you decided that you wanted to replace it with a touched up version. Not a problem. First, navigate to the image you want to replace in Gallery, then click the Edit Photo link on the left sidebar. Then, click the Modify Photo tab along the top. You should see a section labeled "Reupload Photo". Click Browse and browse to the touched up file that you want to upload to replace the existing one, then click Reupload File. Viola! Your new file has completely replaced the old one with no loss of comments, description and such.

Customizing Thumbnails in Gallery

There are two ways you can customize a thumbnail in Gallery: cropping the thumbnail, or uploading a different image to serve as the thumbnail.

Cropping the Thumbnail

Assuming you have Java installed and enabled on your browser, you can use the built-in Java applet to make a custom thumbnail. Simply click the Edit Photo link on the photo, then choose the Crop Thumbnail tab. You can change the shape of the cropping rectangle with the Aspect Ratio controls. You can change the size of the crop selection box by clicking and dragging the Resize Handle. To move the crop selection box, just click and drag anywhere else inside the box.

Uploading a different image

This is especially useful for movies and other media where Gallery can't create a thumbnail of its own. To do this, first create the image you want to use as the thumbnail, then click the Edit Photo (or Edit Item) link. Choose the General tab, then scroll down to the section marked "Custom Thumbnail". Click Browse to browse to the file with the thumbnail you wish to use, then click Save.