Wand - sketch() function in Python

Last Updated : 28 Apr, 2025

Sketch is another artistic special effect present in Wand library in python. sketch() function generates a pencil sketched image in output.For best results, radius value should be larger than sigma.

Syntax :
Python3 wand.image.sketch( radius, sigma, angle) # radius should always be greater than sigma(standard deviation)
Parameter :

Parameter Input Type Description
radius numbers.Real Size of Gaussian aperture.
sigma numbers.Real standard deviation of the Gaussian operator.
angle numbers.Real direction of blur.

Parameter	Input Type	Description
radius	numbers.Real	Size of Gaussian aperture.
sigma	numbers.Real	standard deviation of the Gaussian operator.
angle	numbers.Real	direction of blur.

Source Image:

Example #1:

Python3

# import display() to show final image
from wand.display import display

# import Image from wand.image module
from wand.image import Image

# read file using Image function
with Image(filename ="koala.jpeg") as img:

    # generate pencil sketch image using sketch() function
    img.sketch(0.5, 0.0, 98.0)

    # save final image
    img.save(filename ="rb_koala.jpeg")

    # display final image
    display(img)

Output :

Example #2: To get the best result transform image to grayscale image

Python3

# import display() to show final image
from wand.display import display

# import Image from wand.image module
from wand.image import Image

# read file using Image function
with Image(filename ="koala.jpeg") as img:

    # transform to grayscale image
    img.transform_colorspace("gray")

    # generate pencil sketch image using sketch() function
    img.sketch(0.5, 0.0, 98.0)

    # save final image
    img.save(filename ="rb_koala.jpeg")

    # display final image
    display(img)