In this tutorial you will learn how to transform a color photograph into
a line drawing. I will also show you how to add color from the original photo
back into the drawing. This tutorial is rated for beginners.
In this tutorial you will become familiar with these commands:
The high-pass filter in Adobe Photoshop is used to retain edge details
where sharp color transitions occur and suppress the rest of the image.
The filter removes low frequency detail in an image. It is useful for extracting
line art and large black and white areas from a selected image.
Threshold: A value between 0 and 255 controls how the filter finds edges.
Basically, it defines how much difference there has to be between a given
pixel and its neighboring pixels to consider it an edge point. High values mean
fewer edge points; low values produce more edgy pictures.
First, open the photograph that you want to use. I have selected this image for the amount of contrast in the colors.
Any photograph will work fine though you may need to change the settings on
the adjustments that we make to make your image look right. First you will
need to duplicate the image. You do this by either dragging the image to the
Create a new layer icon in the layers palette or by right clicking on the
background layer in the layers palette and choose Duplicate layer or by clicking on Layer then clicking Duplicate layer
from the file menu.
The first step is to apply the High-pass filter on the duplicated layer.
You do this by clicking on Filter then Other then High Pass from the main file menu.
This filter will find the edges in the image using the contrast in colors in the image.
In the High-pass filter dialoge box, I chose a radius of 4.0 pixels for this image.
With higher resolution images you will need to have a higher radius for the filter
to find the edges correctly. Just use the adjustment slider until you can see
the contrast clearly.
After you have the setting that you want using the high pass filter, we will need to use
the threshold command to remove all of the color and have the edges painted black and the
background as white. Make sure the duplicated layer is selected and the click on Image then click Adjustments then click Threshold from the main
file menu. In the dialogue box that opens, adjust the Threshold level until you get the
edges to show that you want. A higher number will mean more edges will be painted.
With a higher resolution image you would need to set the threshold level to a
higher value. Change the settings using the slider to obtain the results that you
desire for your image. We could stop here and have a nice picture to print out and color
with Crayons or you can let Photoshop color the image using the colors from the original image.
This is the reason we duplicated the image in the first step. Make sure
the duplicated layer is selected in the layers pallet. Then all you need
to do is change the opacity of the line drawing. This will let the colors from
the original image come through to color the new layer with a water color look.
I chose a opacity level of 70%. This lets the colors show through without making
the new layer look like a photograph. You can adjust the opacity in your image until
you get the desire colorization that you want. A lower percentage will let more
colors show through. Now you can save the image using the format that you need. Each step
in this tutorial will add many bytes to the size of the original image. So the end
result will be a file that is about double the size of the original file.
I recommend using the .jpg format. This will let you save the image with higher compression
settings therefore making the file size smaller.
I hope this tutorial has been helpful. There are other ways to create line drawings in
Photoshop, but I feel this is by far the easiest way.
If you have any questions or comments, please don't hesitate to email the author of this tutorial.