Optimize images for printing

From the WhiteWall expert Jan-Ole Schmidt

Optimizing images for printing requires special attention and care. Unlike the use of images on the Internet, where flexibility and space-saving file sizes are paramount, precision and the highest quality are essential for printing. Whether prints in poster format , wall art or high-quality Coffee Table Books - image optimization is crucial for razor-sharp and true-colour print results. This blog post looks at what you should pay attention to in order to get your print products in the best quality and which tips will help you avoid common mistakes.

Why image optimization is so important for printing

Optimizing images for print is fundamentally different from optimizing them for digital media. While speed and loading time are the most important factors on the Internet, quality is paramount in print. Images that look sharp and vivid on the screen can look blurred, pixelated or not true to color in print if they have not been prepared correctly. It is therefore important to understand the differences in the requirements and to optimize the images accordingly.

Printing processes are based on physical media that are affected by a variety of variables, including print resolution, type of press, ink quality and the paper used. Each of these factors can affect the final print quality. The success of a print project is therefore highly dependent on how well the images are prepared for the particular printing process.

The importance of the right resolution

One of the most important factors for optimum image quality in printing is the resolution of the image. The print resolution is specified in dpi (dots per inch) and describes the number of print dots that can be placed on one inch. The higher the basic resolution of an image in pixels, the larger it can later be printed in very good quality. A higher resolution is required for printing than for digital presentation on monitors and smartphone displays. While images for the internet often only require a resolution of 72 dpi, the resolution for printing should ideally be at least 300 dpi. For larger viewing distances, a lower print resolution may also be sufficient. A higher resolution ensures that the image is printed as sharply as possible and without visible pixels or blurring.

If the basic resolution in pixels and/or DPI is not sufficient for the desired print size, the resolution of the image should not simply be artificially increased in an image editing program such as Photoshop. This can lead to blurred images. In this case, there are three options: Re-photograph the image at a higher resolution, choose a smaller output size for printing that matches the resolution of the original image, or use one of the AI-based software solutions that now work very well and manage to enlarge images sharply and in good quality.

Which file formats are supported by WhiteWall?

We support several file formats, which can be used differently depending on the product category. For wall art created via the online configurator, we accept files in JPG, HEIC and TIFF format . These formats are particularly suitable for high-quality image products such as acrylic glass, aluminum prints, prints and canvases.

For Coffee Table Books and photo calendars, we offer a little more flexibility in terms of file formats. Our online software for Coffee Table Books supports JPG and PNG files, while the download software also accepts formats such as BMP, GIF and TIFF. Color profiles can be embedded. As the images are converted into the sRGB color space (red, green, blue) for the production of the image products, we recommend that you do not upload any image data in the CMYK color profile (cyan, magenta, yellow, black), as this may result in undesirable color deviations. The maximum possible file size is 50 megabytes.

Raw files, so-called RAW files, cannot be uploaded when ordering a WhiteWall product. These must first be edited in an image editing program and saved in one of the supported formats such as JPG, TIFF or PNG.

JPEG files should be saved in the highest possible quality in order to minimize the loss of image details. TIFF files are particularly suitable for printing as they are compressed without loss and guarantee high image quality.

Automatic image optimization with WhiteWall

At WhiteWall, we offer automatic image optimization that has been specially developed for customers who have not professionally edited their images or simply do not have the time to deal with image editing in detail. Since November 2022, advanced artificial intelligence (AI) has been used for this purpose, which analyses and recognizes the subject using scene recognition and automatically suggests the optimal settings for contrast, saturation, colour balance and brightening in shadow areas.

In standard mode, automatic image optimization is activated for each photo and set to an optimization level of 70 percent. This value is based on the AI's empirical values and has proven itself for most types of motifs. However, the level of optimization can be adjusted individually. For this purpose, we offer an intuitive user interface that makes it possible to compare the optimized images in a before-and-after view and adjust the level of optimization as required.

Image optimization can be conveniently activated or deactivated in the WhiteWall product configurator via the options menu. A special display in the configurator makes it possible to view the original image and the optimized variant side by side or to compare both variants in a split view. This allows specific adjustments to be made in order to achieve the desired result.

Users who have already had their images professionally edited and do not want any further optimization have the option of setting the degree of optimization to zero percent and activating the corresponding checkbox. By activating the checkbox, the optimization set to zero percent is applied to all further images in the order and saved in the user account. This ensures that no further images in the order are automatically optimized.

What are ICC profiles and how can they be used for image optimization before printing?

ICC profiles (ICC=International Color Consortium) play a decisive role in color management and are indispensable, especially in print preparation. We at WhiteWall offer individual ICC profiles for most of our products and materials, which make it possible to simulate the colors of an image as accurately as possible with regard to the planned print medium before printing. With the help of such profiles, a precise preview of the print result, a so-called soft proof, can be created. A soft proof ensures that the printed image looks exactly as it will be displayed on a calibrated monitor. Our available ICC profiles can be downloaded here.

Important at this point: Our ICC profiles are intended exclusively for soft proofing and should not be used for (color space) conversion. We also recommend not embedding the profiles directly in the image data. ICC profiles are not saved directly in the image processing program, but in the local operating system. On Mac systems, the profiles with the file extension ".icc" can be copied to the folder "MacintoshHD:/Library/ColorSync/Profiles". For Windows users, installation is carried out by simply right-clicking on the downloaded file and selecting the "Install profile" option. This procedure ensures that the profiles are automatically integrated correctly and can be used in programs such as Adobe Photoshop and Lightroom.

A soft proof makes it possible to assess the print or exposure result of the image on the desired print medium in advance. Both the printing or exposure technique and the medium on which the image will be output are taken into account. Programs such as Adobe Photoshop and Lightroom offer the option of selecting the ICC profile of the output medium and adjusting various settings such as render priority and depth compensation. By activating the "Simulate paper color" option, the influence of the paper tone on the color reproduction can also be simulated. This allows specific adjustments to be made to ensure the most accurate color reproduction possible in the printed image.

Which color space and color depth can be processed for printing?

Images can be uploaded to WhiteWall in the RGB color space. CMYK data should be avoided as it is automatically converted to RGB in the production process. This can lead to unexpected color deviations. If no color profile is included in the image data, we assume that the data is available in the sRGB profile. The "GrayGamma2.2" profile is used for grayscale files.

We can process both 8-bit and 16-bit files. The choice of color depth influences the amount of color information that can be displayed. A color depth of 16 bits offers a finer color gradation and more depth of detail, which can be particularly advantageous for complex motifs and professional applications.

The value of a proof

A proof is one of the most reliable ways to ensure that the final product meets expectations. A proof is essentially a test print that allows you to check the colors and print quality of a photo in the desired size and on the desired paper at a reduced price before the final order or a larger print run is produced. The test print is provided with a watermark, which is also displayed in the preview during the configuration process. The test print offers the opportunity to make final adjustments and ensure that all aspects of the print project are optimally prepared.

Test printing is essential, especially for large print jobs or projects with high quality requirements. This avoids costly errors and ensures that the end product meets the exact requirements.

Conclusion: The right preparation for a perfect print result

There are two ways to optimize images for our WhiteWall photo products. Either via automatic optimization, if you want it to be quick and easy, or via professional manual optimization with ICC profiles and soft proofs. The latter gives you full control over colors, contrasts and the overall image quality on the desired print medium. If you follow the above tips and techniques, you can be sure that your print projects will not only look good, but also achieve the desired effect. How about a large-format print in an elegant passe-partout frame, for example?

If you want to be on the safe side, a test print is the best way to optimally assess the end result. After all, nothing is more annoying than a result that does not meet your expectations. With the right approach and attention to detail, you can ensure that your printed images are always of the highest quality.