Inside Cobalt Image PHOTO

        A technical journey inside our app.

Different inside

Welcome to an in-depth exploration of Cobalt Image PHOTO, an innovative application poised to revolutionize image processing on iOS devices. Positioned at the forefront of technological advancement, this app provides users with unparalleled control over their image editing experience.

We’re skipping the academic preamble, catering instead to the curiosity of the audience, and diving straight into the facts: assessing the quality of our white balance and the potency of our exclusive Luma curve. Following that, we’ll delve into the intricate technological processes that drive Cobalt Image PHOTO.

Our White Balance

We’re excited to showcase firsthand the seamless management of white balance in your images, offering the same simplicity and power you’d expect from a desktop raw editor. But now, it’s all on your iPhone, directly applied to the photos you’ve captured, complete with AI enhancements from the latest iPhone models.

These are the starting images with a not even acceptable white balance (all the images below are 8 bit per channel):

We can leverage the consistent background behind the subject in this image and replicate it by identifying the most neutral grey point in the other images using the app as follows:

With a simple click, we get the above results; The distinctive feature of the colour space utilized in the app, OKLab, is its remarkable ability to predict chromaticity with precision and axis orthogonality. This unique characteristic enables the optimal balancing of raster images with exceptional accuracy.

Now, let’s explore the capabilities of other tools. First up, Photoshop on desktop with its powerful curves tool, followed by CameraRaw (Lightroom) on desktop as well; we will see hue shifts, saturation shifts and even exposure changes:


Introducing the Luma curve


When we conceptualized our app, our aim was clear: to consolidate the best of image editing technology into a single, intuitive product. Among its standout features is the Luma curve—a tool highly esteemed in professional-grade software like CaptureOne, yet notably absent in others such as Lightroom or CameraRAW.

But what exactly is the Luma curve?

In technical terms, it’s a curve that distinguishes between the Chroma (colour) and Luma (brightness) components of an image. The algorithms and colour models behind it can vary from simple to complex, and Cobalt has opted for the pinnacle of colour appearance models: CIECAM16.

This sophisticated model enables precise isolation of colour from luminance within an image. Unlike RGB curves, where changes in contrast often impact colour saturation and hue, the Luma curve in CIECAM16 allows for contrast adjustments without compromising colour fidelity or introducing oversaturation.

In the accompanying videos, the distinction between a Luma curve and an RGB curve becomes apparent:

As demonstrated, manipulating the RGB curve alters both contrast and saturation, and subtly, yet detrimentally, affects chromaticity, fundamentally altering colour integrity. Conversely, our Luma curve, operating within the CIECAM16 model, preserves saturation and the true essence of colour.

With our Luma curve, as you start from the already calibrated HEIC by the AI-enhanced engine of the iPhone, you can enhance shadows, reduce the global contrast, apply a colour signature and adjust contrast in portraits, all while maintaining the integrity of colour—directly from your iPhone, without the need for desktop applications. It’s a powerful tool that puts professional-grade editing capabilities in the palm of your hand, ensuring your photos always shine with the utmost quality.

Improve what is already good

Focusing on editing HEIC files in our app allows us to leverage the best of Apple’s technology. Here are the advantages of this choice:

-Higher Image Quality: HEIC files offer superior image quality compared to JPEG files due to the use of more advanced compression algorithms. This results in smaller file sizes without significant loss of quality. Even after editing, the image retains more details and colour information.

-Extended Dynamic Range: While RAW files offer the widest dynamic range, HEIC files capture a broader dynamic range compared to JPEG files. This means HEIC images contain more details in both highlights and shadows, providing greater flexibility during editing to recover details in overexposed or underexposed areas.

-Efficient Storage: HEIC files are more storage-efficient compared to RAW files. RAW files contain unprocessed data captured by the camera sensor, resulting in larger file sizes. HEIC files achieve similar quality with smaller file sizes, making them easier to manage and store, especially on devices with limited storage capacity.

-Convenience: Editing HEIC files directly on an iPhone is convenient as it avoids the need for additional conversion steps. RAW files require processing and conversion to a standard image format like JPEG or TIFF before editing, adding extra time and effort. Editing HEIC files natively within iPhone editing apps is more streamlined and user-friendly.

-Compatibility: HEIC is increasingly supported by various platforms and software applications. While RAW files may require specific software or plugins for editing HEIC files can be edited using a wide range of image editing software, including popular mobile editing apps.

-Speed: Editing HEIC files can be faster compared to RAW files, especially on mobile devices with limited processing power. RAW files are larger and require more computational resources for processing, whereas HEIC files are smaller and more optimized for efficient editing on mobile devices.


Our experience for better images

The experience of Cobalt-Image in processing RAW images has played a crucial role in conceiving a development pipeline based on the Apple HEIC format and integrating the advantages of iPhone artificial intelligence with our image editing technology.

Cobalt-Image has accumulated extensive experience in processing RAW images, fully understanding the needs of users who want to maximize the quality and flexibility of their images during the editing process. Apple HEIC offers robust file compression without compromising image quality, making it ideal for users who want to save storage space without sacrificing visual quality. Additionally, HEIC supports advanced features such as high-fidelity colour management, and representation of high dynamic range (HDR), providing a versatile platform for image editing.

iPhones are equipped with powerful artificial intelligence engines, including machine learning and computer vision, which can be leveraged to enhance image editing. Cobalt Image PHOTO, with its development pipeline, integrates and complements the work done by Apple’s artificial intelligence, allowing the user to edit HEIC files with the same capabilities as a RAW, keeping the advantages of unique features as the live depth of field of the portrait mode or the AI long exposure.

By using iPhone artificial intelligence together with Cobalt-Image’s editing technology, users can benefit from an advanced editing experience that combines sophisticated algorithms with an intuitive user interface. This approach enables users to achieve stunning results with ease, thanks to the combination of advanced processing capabilities and intuitive editing tools.

Embrace change, not destruction.

White balance is a critical aspect of image editing because it ensures that the colours in an image appear natural and accurate, reflecting how the human eye perceives them in real life. When you take a photograph, the colour temperature of the light source can vary, affecting how colours appear in the image. Different light sources emit light at different colour temperatures, ranging from warm (yellow-orange) to cool (blue).

The decision to use OKLab instead of CIELab for white balance adjustments in your app is a strategic one, driven by several factors that make OKLab a more suitable choice for this particular application. Below are some reasons why OKLab might be preferred over CIELab for white balance adjustments:

Perceptual Uniformity: While both OKLab and CIELab are designed to be perceptually uniform colour spaces, OKLab offers certain advantages in terms of perceptual uniformity. OKLab ensures that changes in colour are perceived consistently by the human eye, making it an ideal choice for applications where accurate colour perception is crucial, such as image editing.

Orthogonality: OKLab is designed to have orthogonal (linear) lightness, which means that changes in lightness are independent of changes in chromaticity. This property can simplify calculations and make it easier to manipulate colours while maintaining their natural appearance, particularly in algorithms like white balance adjustments.

This aspect is particularly evident in the blue gradients, where the CIELab model fails to predict the exact chromaticity:


By adopting the OKLab model, we ensure that white balance adjustments are non-destructive in landscape photos, or generally in all photos where preserving the blue channel is important.

The best technology, for the best photos

For editing Exposure, Contrast, Saturation, and Luma curve parameters, we have chosen the most advanced colour model currently available: CIECAM16 (International Commission on Illumination Color Appearance Model 2016) is a colour appearance model designed to predict how colours are perceived under various viewing conditions. Utilizing CIECAM16 in your app offers several advantages:

-Perceptual Uniformity: CIECAM16 is designed to be perceptually uniform, meaning that equal changes in colour parameters result in roughly equal perceptual changes in colour appearance. This ensures that adjustments made in CIECAM16 space correspond well with how humans perceive changes in brightness, contrast, and colourfulness.

-Adaptation to Different Lighting Conditions: CIECAM16 accounts for changes in viewing conditions, such as different levels of illumination and viewing environments. By considering factors like the chromatic adaptation, the degree of illumination, and the surrounding colours, CIECAM16 ensures that colour adjustments are consistent and visually pleasing across different viewing conditions.

-Colour Appearance Modeling: CIECAM16 takes into account the complex interactions between colour, lightness, and surrounding colours, providing a more accurate representation of how colours appear to the human eye. This enables more precise adjustments to exposure, contrast, saturation, and luma curves, resulting in images that appear more natural and visually appealing.

The CIECAM16 model ensures total encoding of the Display P3 gamut, thus preserving all information without any loss:

Always striving for the best, with every step

Our LUTs are our pride; what has made Cobalt Image’s desktop offering unique.
The meticulous work in researching and calculating LUTs (Look-Up Tables) by Cobalt Image has been crucial in achieving its renowned emulations. LUTs are essential tools in digital image processing, allowing for the application of complex transformations to colours and contrast in images accurately and reproducibly.
To obtain high-quality emulations, an in-depth research process was necessary to understand the distinctive characteristics of different photographic films, development processes, and lighting conditions. This research involved analyzing samples of images from a wide range of sources, including films, photographic prints, and digital images.

Once fundamental knowledge was acquired, the process of calculating LUTs required careful experimentation and optimization to ensure maximum accuracy and fidelity in emulating the desired characteristics. This involved accurately manipulating colour data to match the specific profiles of the desired films or emulations.
Furthermore, meticulous work included verifying and validating the LUTs through thorough testing on a variety of test images and continuous iteration to refine and perfect the emulations.
Thanks to this rigorous and meticulous process, Cobalt Image has been able to create high-quality LUTs that offer accurate and realistic emulations of the characteristics of the most renowned photographic films, distinguishing itself as a leader in the digital emulation industry.
In applying our LUTs, we have chosen the best among RGB spaces: ProPhoto. Using ProPhoto as a working space for applying LUTs offers several distinct advantages:

-Wide Gamut: ProPhoto encompasses an extremely wide gamut, covering a larger range of colours compared to other RGB colour spaces such as sRGB or Adobe RGB. This wide gamut allows for more vibrant and saturated colours, which is particularly beneficial when applying LUTs that involve significant colour transformations.

-Full Encoding of Display P3 Gamut: ProPhoto has the capacity to fully encode the Display P3 gamut. By using ProPhoto, which can encompass the entire Display P3 gamut, you ensure that all colour information is preserved and accurately represented.

-Low Cross-Talking Channel: ProPhoto has a low cross-talking channel, meaning that colour channels have minimal influence on each other. This helps maintain colour separation and fidelity during colour grading and LUT application, reducing the risk of unintended colour shifts or artefacts.

-Resilient Color Shift with RGB Curves: ProPhoto is more resilient to colour shifts when applying RGB curves compared to other colour spaces. This means that when adjusting individual colour channels using RGB curves, ProPhoto better preserves the original colour relationships and minimizes colour distortion or contamination.

Safely, your colours without the risk of out-of-gamut

In our development pipeline, there is always a compression LUT at the end of the chain. This particular LUT has been designed to ensure that any editing done in the earlier stages allows all colours to fit within the Display P3 gamut. This way, you won’t have to worry about any out-of-gamut or impossibly saturated colours.