How To Create A Sketch Effect
This tutorial will show you how to create a sketch effect. I will use GIMP http://www.gimp.org to show you the different steps, but you can probably transfer these steps to many other photo edit programs.
1. Load Photo
Load your original image. This for example may look good as a sketch.
2. Duplicate Layer
To duplicate a layer go to //Layer//Duplicate Layer//
3. Soften, but keep details (high pass filtering)
Now we need to soften the top layer. Select the top layer and use the Gaussian Blur by going to //Filters//Blur//Gaussian Blur…//
I used in this example the radius of 8. You have to play with this setting a little, but in generally, as larger the number as fatter the lines in the sketch.
4. Invert, Blend, Merge
Now we need to subtract this from the original image. First invert the colors on the top layer by going to //Layer//Colors//Invert//
Blend the layers by lowering the opacity of the top layer down to 50.
Merge the two layer by selecting the top layer and going to //Layer//Merge Down//
5. Level Adjustment
We can increase the contrast with adjusting the levels. Go to //Layer//Colors//Levels
Move the left slider to the 100 position and the right slider to 155.
To turn the background to white, we need to first desaturate the image.
Go to //Layer//Colors//Desaturate//
7. Level Adjustment
With another adjustment of the levels we can turn the background white.
Go to //Layer//Colors//Levels…// and move the right slider to 128. Move then first the left slider to the right and then adjust the middle slider. You have to play around to find the best setting that create a minimum of noise.
8. Clean Up
At last you have to remove noise that you do not like to see in the image. For example you could use the eraser tool or just paint with white.
9. The Result
Let’s just for fun hand-color the sketch.
Henrik Lehnerer http://photo.hlehnerer.com