How to Convert an Image to Black-and-White Grayscale using Java

Removing color from an image both reduces the complexity of the file and creates a the familiar “black & white” aesthetic effect. With our Grayscale API, you can easily convert your images to black-and-through a simple color removal operation and return the encoding to create your new file. It’s free & easy to use — just register a free account on our website (free accounts come with a limit of 800 API calls per month: perfect for small-scale projects & startups) and follow the instructions included below to structure your API call in Java.

Our first task is to install the API client. We can get that started by including a reference in the pom.xml repository:

<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>
</repositories>

We can wrap up installation by adding another reference to the pom.xml dependency:

<dependencies>
<dependency>
    <groupId>com.github.Cloudmersive</groupId>
    <artifactId>Cloudmersive.APIClient.Java</artifactId>
    <version>v4.25</version>
</dependency>
</dependencies>

Now we can call the color removal function. First include the imports at the top of your file, then pass your image file path through the imageFile parameter:

// Import classes:
//import com.cloudmersive.client.invoker.ApiClient;
//import com.cloudmersive.client.invoker.ApiException;
//import com.cloudmersive.client.invoker.Configuration;
//import com.cloudmersive.client.invoker.auth.*;
//import com.cloudmersive.client.FilterApi;
ApiClient defaultClient = Configuration.getDefaultApiClient();
// Configure API key authorization: Apikey
ApiKeyAuth Apikey = (ApiKeyAuth) defaultClient.getAuthentication("Apikey");
Apikey.setApiKey("YOUR API KEY");
// Uncomment the following line to set a prefix for the API key, e.g. "Token" (defaults to null)
//Apikey.setApiKeyPrefix("Token");
FilterApi apiInstance = new FilterApi();
File imageFile = new File("/path/to/inputfile"); // File | Image file to perform the operation on.  Common file formats such as PNG, JPEG are supported.
try {
    byte[] result = apiInstance.filterBlackAndWhite(imageFile);
    System.out.println(result);
} catch (ApiException e) {
    System.err.println("Exception when calling FilterApi#filterBlackAndWhite");
    e.printStackTrace();
}

Now just make sure to include your API key where shown in the code comments, and you’re all set to go!