top of page

Image Colorization: Converting Black-and-White Image to Color Image

Updated: Oct 19, 2023

Introduction to Image Colorization

Image colorization is the process of adding color to grayscale or monochromatic images. Traditionally, this was done by hand by artists who would manually paint over black and white photographs or films. However, with the advent of deep learning and neural networks, this process has been revolutionized. Modern techniques can now automatically predict the colors in a grayscale image with remarkable accuracy, breathing life into old or colorless images.

In the context of our project, we harness the power of deep neural networks to achieve this goal.

Here are some of the primary applications:

Film and Television

  • Restoration of Old Movies: Many classic black-and-white films have been colorized to appeal to modern audiences.

  • Documentaries: Making old footage more engaging by adding color.


  • Restoration of Old Photographs: Bring life to old family photos or historical photographs.

  • Professional Photography: Occasionally, photographers might opt to shoot in black and white (or convert a color photo to black and white) and then selectively colorize some elements for artistic reasons.

Digital Art and Animation

Artists can quickly sketch in grayscale and then use colorization tools to bring their creations to life.

Historical Research

Colorizing old photos can make historical periods feel more immediate and relatable to the present day. This has been done for major world events, bringing a new perspective to them.


For teaching subjects like history, colorized images can make content more engaging for students.


Occasionally, image colorization techniques might be used in forensic image analysis, either to enhance certain features of an image or to help in visualizing specific details.

Gaming: In some video games, especially ones that might have a flashback or historical component, developers might use colorization techniques for certain scenes or images.

Augmented Reality (AR) and Virtual Reality (VR): Bringing black-and-white images or footage into colored 3D environments.

Commercial and Advertising

Making vintage imagery suitable for modern advertising campaigns.

Deep Learning and AI Research: Image colorization is a popular problem in the field of computer vision and deep learning. Developing algorithms to colorize images helps in pushing the boundaries of what machines can "perceive" and "understand" about images.

Accessibility: Helping individuals with certain types of color vision deficiencies or other visual impairments by adjusting or enhancing image colors for clearer viewing.


class ImageColorizer:
    A class used to colorize grayscale images using a pre-trained deep neural network.

    def process_image(self, img_path: str) -> np.ndarray:
        Processes a grayscale image to colorize it using the pre-trained deep neural network.

    def display_image(self, img_path: str) -> None:
        Displays the colorized version of a grayscale image using the pre-trained deep neural network.

The ImageColorizer class, as its name suggests, is designed for the task of image colorization. Its primary function is to add color to grayscale images using a deep neural network model.

process_image Method

  • Parameters:

img_path: This parameter is of type str which is a path to the grayscale image that needs to be colorized.

  • Returns:

np.ndarray: The function is expected to return a Numpy array. This array will likely represent the colorized version of the input grayscale image.

  • Purpose:

As per the method name and its signature, this function should take a path to a grayscale image, process (colorize) this image using a pre-trained neural network, and then return the colorized image in the form of a Numpy array.

display_image Method

  • Parameters:

img_path: This parameter is of type str which is a path to the grayscale image that is to be displayed after colorization.

  • Returns:

None: The function is not expected to return any value.

  • Purpose:

The primary function of this method is to display the colorized version of the grayscale image. It will likely use the process_image method (or a similar process) to colorize the image and then use some visualization library (like matplotlib or OpenCV) to show the colorized image to the user.

# Testing
img_path = "image.png"  # Replace with your image path
colorizer = ImageColorizer()

img_path = "image.png"

This line initializes a variable named img_path with the string value "image.png". This is a placeholder and represents the path to a grayscale image that you want to test with. The comment above this line (# Replace with your image path) suggests that you should replace the "image.png" string with the path to your specific grayscale image if you want to test with a different image.

colorizer = ImageColorizer()

Here, an instance of the ImageColorizer class is being created. The colorizer variable now holds this instance, which means you can use colorizer to access the methods and attributes of the ImageColorizer class.


This line calls the display_image method of the ImageColorizer class using the colorizer instance. The method is provided with the img_path as its argument.

As we can see, we have obtained color images from the black-and-white input images.

We have provided only the code template. For a complete implementation, contact us.

If you require assistance with the implementation of the topic mentioned above, or if you need help with related projects, please don't hesitate to reach out to us.

18 views0 comments

Recent Posts

See All


bottom of page