Vectorize a Landscape Photo Into a Watercolor Painting

Final Image

Here is a preview of the image that we are going to be creating:

Introduction: the easiest way

There are several interesting and creative ways to create vector illustrations. The technique obviously depend on the final work you want to get, the kind of image you have (if you have one), and your experience to do the job.
The most common way are three, you can start from a blank canvas, from a sketch, or use a photo.
Starting from a blank canvas is the most difficult way. You have no lines to follow and you are alone with your creativity. The bad side of the technique is that you need to be really able and having strong hand-drawing skill.
The second option is hand-drawing a sketch of what you want first. Even to do this step you need to be able with hand-drawing but, once scanned the image, youíll have a template to work to.
The last way is the easiest one and that is the one we are going to use with this tutorial. You start from a photo of the thing you want to vectorize and use it as template building it up level by level.

Choosing the Right Photo

Once chosen the procedure the next extremely important step is choosing the right photo. Not anyone is good to start with. The right photo has to be well contrasted and not too dark but with definite distinction between light and shadow areas. This will help you in identifying the contours.
If you are not comfortable with taking picture than you can purchase images, from a stock photo service, which are suitable for your upcoming creation. Anyway the best thing to do is using shots from your own so that you are not occurring in copyright problems.

Preparing the Image in Photoshop

Step 1

Once identified the technique and chosen the image there are still few steps to accomplish. Before we get started are a few basics need to be covered. To make the vectorization working better once within Illustrator platform we need to prepare it by adjusting lights and levels, turning the image in w/b and deleting some areas of the picture.
As suggested, I prefer taking the picture which I use by myself. Last weekend, having a walk around Iive taken several pictures of the Turinís Mole Antonelliana. Among the various shots Iíve selected this nice and clear pic of the historical monument:

It contains several typical city elements: the Mole, the characteristic dormer windows, a beautiful streetlamp and an old-style tram recently restored. I think it well represent Turin and its beautiful elegance.
Open up the image in Photoshop. Adjust contrast and lights as you like and turn the image w/b by going to Image > Mode > Grayscale.

This is what you get:

Duplicate the level as backup and go ahead.

Step 2

Click CTRL + L (or CMD + L) to open the Level panel.
Adjust levels so that the gray in the sky disappears and leaves all around the main subject clean. Move the handles so that you clean the borders from exceeding gray or black shadows. Move the white handle toward the right side and the black handle toward left has shown below.

Step 3

Go then to Filter > Stylize > Trace Contour
This feature traces the areas in the picture that have the most contrast in value to each other.

Set Upper Edge and a tracing level high to better outline the image. Experiment with the options. These are the value and setting which Iíve used.

Step 4

Once that the photo has been stylized we need to make the lines darker. Duplicate the level, and apply a Multiply blending.

This is what we get.

Step 5

Select the white color by using the magic wand tool and refine the selection by going to Select > Similar.

Delete the white color and leave the image in a transparent level.

Step 6

Select the Rubber Tool. From the Rubber option panel select a dry brush, increase the size and delete part of the artwork. Consider that too many details will make the Illustrator file heavy to manage once vectorized. The cleaning up of the image will avoid a useless proliferation of anchor points.

In the example Iíve removed branches from the trees. In addition Iíve removed the border making the image suitable to fit different shapes without the need of constraining it in a frame.
Have you reminded yourself to save? If not (bad boy/girl!) than do it now.

Polished and with its undefined silhouette the image is now ready to be managed in Illustrator and turned in a vector.

Vectorizing the Image

Step 7

Create a new document by going to File > New.
The document size depending on what your artwork you are going to use for. Iíve selected a 15 x 25 cm size to be sure I can use it as design for a merchandising t-shirt.
In the advanced options choose CMYK as color mode because it has printing use, and High Resolution Raster Effect.

Step 8

Take your photo already managed with Photoshop and import it into Illustrator. To do that go to File > Place and choose the .psd file which you have previously saved.

Place it inside your artwork area.

Step 9

Keep the object selected and go to Object > Live Trace > Tracing Options

Step 10

This step is extremely important. The Tracing Option Panel contains a lot of parameters which are going to affect the vectorizing result. Let’s have a close reading to them.

Preset Specifies a tracing preset.
This change between different presets that Illustrator offers.
Mode
Specifies a color mode for the tracing result.
It allows to switch from black and white, grayscale, or color mode.
Threshold
Specifies a value for generating a black and white tracing result from the original image. All pixels lighter than the Threshold value are converted to white; all pixels darker than the Threshold value are converted to black. (This option is available only when Mode is set to Black and White.).
Palette
Specifies a palette for generating a color or grayscale tracing from the original image. (This option is available only when Mode is set to Color or Grayscale.)
To let Illustrator determine the colors in the tracing, select Automatic. To use a custom palette for the tracing, select a swatch library name. (The swatch library must be open in order for it to appear in the Palette menu.).
This allows you to specify your own color.
Max Colors
Specifies a maximum number of colors to use in a color or grayscale tracing result. (This option is available only when Mode is set to Color or Grayscale and when panel is set to Automatic.).
Obviously the more are the color the heavier is the file.
Output To Swatches
Creates a new swatch in the Swatches panel for each color in the tracing result.
This will give you a control on the colors automatically picked up from the image so that you may change them later.
Blur
Blurs the original image before generating the tracing result. Select this option to reduce small artifacts and smooth jagged edges in the tracing result.
Resample
Resamples the original image to the specified resolution before generating the tracing result. This option is useful for speeding up the tracing process for large images but can yield degraded results.
Fills
Creates filled regions in the tracing result.
Strokes
Creates stroked paths in the tracing result.
Max Stroke Weight
Specifies the maximum width of features in the original image that can be stroked. Features larger than the maximum width become outlined areas in the tracing result.
Min Stroke Length
Specifies the minimum length of features in the original image that can be stroked. Features smaller than the minimum length are omitted from the tracing result.
Path Fitting
Controls the distance between the traced shape and the original pixel shape. Lower values create a tighter path fitting; higher values create a looser path fitting.
Minimum Area
Specifies the smallest feature in the original image that will be traced. For example, a value of 4 specifies that features smaller than 2 pixels wide by 2 pixels high will be omitted from the tracing result.
Corner Angle
Specifies the sharpness of a turn in the original image that is considered a corner anchor point in the tracing result.
Raster
Specifies how to display the bitmap component of the tracing object.
Vector
Specifies how to display the tracing result.
[Italic text from Adobe Illustrator CS4 Help http://help.adobe.com/en_US/Illustrator/14.0/WS714a382cdf7d304e7e07d0100196cbc5f-6226a.html]
Not cited from the Adobe Help we still have:
Ignore White
It omits white from the vectorization. This means that all white areas will be empty and left transparent.
Preview
Le t you see what you have to expect from your settings. Pay attention that depending on the inserted values the preview may slow your computer in the image calculation process.
Info
The shown details hereby listed are the result in terms of anchor points, colors, etc, which coming from your chosen options.

Step 11

Go to Object > Live Trace > Expand the image shows the paths and you can edit whatever you like. This will give you a great flexibility if you need to modify shapes or anchor points.
Once finished lock the level and save.

Step 12

Once you have accomplished this step the main part of the work is completed. At this point the only thing to do is making it better by adding some creative elements. In the example, Iíve decided that my Mole Antonelliana artwork have to look like a watercolor painting. Thatís why I need now is the right tool for the job: a watercolor brush for Illustrator.
You can produce by yourself watercolor brushes or, otherwise, you can use free resources from the web to provide you with the elements you need to finish your artwork. Please, always pay attention to copyright and license of use for any resource you get. Respect your fellows work!
In the example Iíve downloaded the nice Vectips Watercolor Brushes from Vectips.com http://vtfreebi.es/65MP).
Download the resource and load the brush by going in the brush palette. Select the drop down menu and choose Open Brush Library > Other Library. Load the brush from the folder where you have saved it

Step 13

Letís start to paint our artwork to make it more attractive.
Create a new level. Choose brush number 5 and draw a line onto the tram. Change the color with a bright green one.

Step 14

Select brush number 1, pick a bright yellow color and draw few lines around the city lamp.

Step 15

Select brush number 6 and a dark green color. Make irregular circle in the branches area.

Step 16

Select brush number 5 again and with a gray color paint the city lamp pole.

Step 17

Choose cyan color and select brush number one. Make a circle in a new layer and move this layer behind that one which contains the Mole outline.

Step 18

We still can add a touch of color to the Mole by selecting brush n. 4 and red and drawing a single vertical line.

Step 19

Do not forget you sign! Otherwise how can people recognize your work? Sign in a new layer by using your tablet or, otherwise, scan your sign and follow a similar workflow as that one just accomplished to vectorize it well. To stick with the general style of the artwork Iíve handwritten it with my tablet.

And We’re Done!

Here below you can see the final image we get. The subtle and elegant watercolor effect matches perfectly with the general elegance of Turin as city. The outline is clear but detailed, really different form a cartoon style or a simple black silhouette skyline.

As said I think it is a perfect artwork to be printed on city merchandise. Here below Iíve mounted it on a t-shirt to let you see what I mean.
What do you think about?

I hope that you enjoyed this tutorial and would love to hear your feedback on the techniques and outcome.