Artists have long combined color with the strength and definition of pen and ink drawings. In the simplest cases, the effect is called a "Wash", in which one or two shades of watercolor are used to create a feeling of depth. This is often seen in Old Master drawings. A more colorful technique combines Gouache (watercolors mixed with chalk to make them thicker and more opaque) and India Ink. This method was once very popular for producing commercial illustrations

This tutorial will show you a technique for producing such a colored line drawing from a photo. The lines in some cases can be very subtle. The effect seems to work best when the subject is architectural (lots of nice straight lines), but almost any image can be used.

Start with a suitable image, preferably one with a depth of 16 million colors. If you start with a GIF (which has only 256 colors), be sure to increase your color depth to 16 million (Colors > Increase Color Depth > 16 Million Colors.) before you begin.  Here I've used a photo that I took of McCormick Hall, on the campus of Hastings College. The title graphic above, by the way, is an image of the College's Art Center.

To begin, we need to remove some of the detail. We want broad areas of color. To do this we use one of the Noise filters, Edge Preserving Smooth (Effects > Noise > Edge Preserving Smooth.) Set the Amount of Smoothing to 25.

Next, we want to sharpen the edges just a bit. Go to Effects > Sharpen > Sharpen More.

Now we're going to use a Mask created from our image to create the dark outlines. Start by making a copy of you image window (Window > Duplicate.) A new copy of your image should pop up. Be sure to keep track of where your original window is, because we're goign to return to it after we create our Mask.

We need this new image to have very clearly delineated edges and very little fine detail, so the next few steps are designed to accomplish this. First we apply the Edge Preserving Smooth again (Effects > Noise > Edge Preserving Smooth.) As we did last time, set the Amount of Smoothing to 25.

Again apply the Sharpen More filter (Effects > Sharpen > Sharpen More.)

Finally, Enhance the edges (Effects > Edge > Enhance.)

Here's where we start to see the edges that are going to show up in our final image. Trace the contour of the drawing (Effects > Edge > Trace Contour.) This gives a series of colored outlines on a white background.

Now Grayscale your image to create the final mask template.(Colors > Grey Scale.)

Take note of the name of your mask image, because you'll need to know later. Now minimize it and return to your original image. Start by duplicating your background layer (Layers > Duplicate.) In your Layers Menu you should see two layers listed: "Background", and "Copy of Background." Use the Layers Menu or Layer Palette to make the Background Layer the active layer. Next, choose your Flood Fill tool and then set the Foreground color to Black. In the Tool Options palette, set the Blend Mode to Normal, the Match Mode to None, and the Opacity to 100. Click on your image. You should actually see absolutely no change, because your top layer is covering up what you did. But if you go to the Layer Palette and hold your cursor over the Background layer, you should see a thumbnail picture of a simple black image.

Next we apply the mask to start creating those dark outlines. A mask is simply a template that PSP can use to make certain parts of a layer transparent. In our case, we're going to use the outline image that we created, and use that to make our mask. All of the dark (black and gray) areas will become transparent, all the white areas will stay opaque. The transparent areas that we create will allow the black background layer to show through.

To add the mask, first return to your second layer by choosing it in the Layers Menu or the Layer Palette. Be sure that the Layer labelled "Copy of Background" is the active one. Now go to the Masks Menu. Choose New > From Image. In the dialogue box that pops up, for the Source window pick the name of the outline image you made, check the Source Luminance box, and be sure that the Invert Mask Data box is UNchecked. This should add some dark otlines to your image.

To create the final effect, simply Edge Enhance twice (Effects > Edge > Enhance.)

You may want to do a few touch-up steps on your final image. Below I cleaned up the subtle contour effect in the blue sky, and spruced up the crimson on the two banners hanging from the light post in the lower left.

Though the effects works nicely on images of buildings, it can be used on almost anything. Below is an image of an eagle from Art Today that was treated using the steps outlined above.