The Watercolored "Pen and Ink"
Sketch Technique

I have always liked loose pen and ink drawings, and soft light-colored watercolor paintings are my favorite kind of painting. This technique was developed to combine these two kinds of art. To demonstrate the use of this technique we will use a picture of an urn that I found sitting on the front porch of a fancy home in Charleston, South Carolina. The picture was taken with a Nikon 950 digital camera that was set to fine mode, which resulted in the 1600x1200 pixels image that is shown to the right. 

STEP 1:  Make a second copy of the original image‹After opening the image "urn-original.tif", you will need to make a copy of it as you will need one image to make a pen and ink sketch, and a second image will be needed later when you begin coloring the sketch. To make a copy, Select Image > Duplicate and then name the new image ³pen-ink.tif² before hitting the OK button.

STEP 2:  Turn one image into a black and white line drawing ‹Now click on the ³urn-original.tif² image to begin the process of turning it into a pen and ink sketch. To turn it into a black and white image, select Image > Adjust > Desaturate and then click on the OK button.

STEP 3:  Change b&w image into pen and ink sketch‹Next we want to make the sketch. Select Filter > Blur > Smart Blur. You will get the dialog box shown to the right..

Set Quality to High and set Mode to Edge Only. Once these settings are made, you can begin adjusting the Radius and Threshold settings to get the quality of drawing that you want. To see the results of the current settings, move your cursor over the image box. You can click on the image and the Hand cursor will appear allowing you to select the portion of the image you want top view. As we want an accurate sketch of the flowers without too few or too many lines, I have dragged the image around until it is on several of the flowers. With some experimentation, I finally chose a Radius of 25.0 and a Threshold of 35.0. Then with a click on the OK button, you'll get white lines on a black background drawing.

Note: This image is a good example of an image where it is hard to get a nice pen and ink sketch, as the edges are not properly delineated. The Smart Blur filter works on image contrast and you may find that there is too much, or two little contrast. For images like this one, you will want to preprocess the image by setting Levels. To set levels, select Image > Adjust > Levels. Alternatively, or in conjunction with levels, you can use Image > Adjust Curves (See below) and select a curve that will allow the Smart Blur filter to give you the results you want.

Note:  Once the pen and ink sketch is complete, you may decide that the line weight is too small or you may want to vary the character of the lines. In these cases, you should try Filter > Artistic > Poster Edge. Again, with some experimentation, you¹ll find you can create some wonderful lines that are bolder than those initially created by the Smart Blur Filter. 

Now we need to turn the white line on a black background image (it looks like a scratch board drawing) into a black line on a white background. To do this, simply select Image > Adjust > Invert and you will have the image shown just below and to the right.

Note:  Stylize > Find Edges is a much more frequently used filter to make a line drawing. However, I find I get much better results from the Smart Blur filter and they are line drawings not line drawings with grayscale pencil smudges like you get with the Find Edges filter. 

STEP 5:  Transform the second color image into a watercolor-like painting‹Our next step is to create a light watercolor wash that we can lay over the top of our pen and ink sketch. To accomplish this, we need to return to the original image and do some work on it. After clicking on the ³urn-original² image, select Filter > Artistic > Dry Brush and set Brush Size to 2, Brush Detail to 8, and Texture to 1‹then click on the OK button. This helps make our image look a bit more like a painting. Once again we need the assistance of our Smart Blur filter. Select Filter > Blur > Smart Blur. This time however, we need to make sure we change the mode setting to Normal while we again use a Quality of High. In this case, I used a Radius setting of 10.0 and a Threshold of 50.0. After making the appropriate settings click OK and you'll see how this filter softens the hard edges that were made by the Dry Brush filter.

STEP 6: Combine both images: We are now ready to blend the two images together. Once again, select the pen-ink.tif image and copy it by selecting Select > All, and then Edit > Copy. Then, select the modified urn-original.tif image and select Edit > Paste to paste the line drawing over the top of the colored image. To get the color to show through the line drawing, open the Layers dialog box if it is not already open and click on Layer 1‹which should be the line drawing. Then, select Soft Light as the overlay method and you will get a painted "pen and ink" sketch like the one shown at the top of this article.

Step 7:  Fine-tune image colors‹Our final step is to adjust the colors of the image to suit our taste. To get the final image shown on the first page, I applied the following settings in the specified order‹order is important! To apply these color settings, you must select the background layer (or colored image layer) in the Layer dialog box.

1.      Set Hue / Saturation settings to: -50, -20, 0 by selecting Image > Adjust > Hue / Saturation.

2.      Set Levels to 0, 1.0, 180 by selecting Image > Adjust > Levels.

3.      Set Color Balance to: 16, 0, -16 for highlights by selecting Image > Adjust > Color Balance.

To permanently combine these two images, select Layer > Flatten Image. After making the final color changes, the image will look like the one shown at the top of this page. Well almost I should say‹the real image looks much better than the compressed image shown above. When this image is printed on a quality watercolor paper with a photographic quality ink-jet printer, the image looks even better!

Note:  There are a number of other options you might like to consider, including adding a texture by selecting Filter > Texture > Texturizer, and then selecting something like Canvas. The final image will also look better if an appropriate edge treatment is applied. An edge treatment takes away from the hard square look of the original digital image and makes it look more painterly. One last tip‹add your hand-painted signature and you'll have a work of art.