Taking a much closer look at pixels with Kaleidoscope 6.5

With Kaleidoscope 6.4 we introduced a complete rewrite of the Image Comparison. With that groundwork in place, we can now start to build on it and innovate further.

Pixel Comparison in Kaleidoscope 6.5 is the first major step—a new way to inspect and compare the exact values of individual pixels, down to the smallest color differences.

Why Pixel Comparison?

The Image Comparison in Kaleidoscope has always been excellent at answering the question “Do these images look the same?” Different views help you evaluate changes in images — from getting an overview with the Two-Up view to spotting subtle differences using One-Up, Split, and Difference views. But when working with color-critical assets — icons, screenshots, photos, or export pipelines — the real question is often:

“What exactly changed in those pixels?”

The new Pixel Comparison is designed to answer that question by letting you progressively inspect and compare the precise values of individual pixels in both images.

Comparing two versions of the same photo in two different color spaces. It’s hard to tell the exact differences.

Meet Pixel Comparison

Pixel Comparison lives in a dedicated inspector sidebar. As you move your cursor across either image, it continuously samples the underlying pixels of both images. The sampled colors are shown in large swatches along with their hex color values — side by side for both images. This makes it easy to quickly explore changes interactively.

With the Pixel Inspector sidebar enabled, color details are shown and continuously update as you hover pixels of either image.

Notes:

The color swatches try to display the pixel color as accurately as possible, given the capabilities of your display.
For the hex color values, if a color can’t be represented in sRGB color space, Kaleidoscope shows a close approximation and makes that explicit. There’s also a warning if that hex color has been clamped.

From color swatches to exact values

At a glance, those swatches and hex values help a great deal in understanding image colors. But in many cases, there’s much more to a color difference than a simple hex color value in sRGB color space.

To explore deeper, Kaleidoscope also displays:

Exact color values of all channels in the image’s native format (rendered in RGB). This can range from 1 channel in case of a grayscale image to 4 for color images with an alpha channel.
Pixel coordinates within the image. This is relevant when comparing images of different sizes.
Pixel dimensions of each image.
Color format, including the real (used) ranges of all channels.
The embedded color profile.

Next to the A and B icons, the Pixel Inspector shows all color channel values in the native format of the image.
It also displays the coordinate sampled, image size, color format, value ranges, and color space.

By now, you might be wondering what it’s all about with that blue text? Similar to the File Properties, we are using a blue color to show you where values differ. For color (channel) values, if they differ but are very close to each other, we even use bold type to highlight that small change.

Understanding differences at a glance

But it doesn’t stop there! To make differences immediately understandable, the Pixel Comparison also shows a single difference value for each pixel, expressed on a scale from 0 to 1. This value matches the Proportional mode used in Kaleidoscope’s Difference View. The colors used in the bar next to the difference value are the identical and different colors defined in Settings > Images.

Compare across color formats

There’s one more level to explore: different problems call for different perspectives. Pixel Comparison lets you inspect and compare pixel values across multiple color formats: RGB, HSB, HSL, and Lab.

This makes it easier to understand whether a change affects brightness, saturation, hue, or perceptual color distance — not just raw RGB channel values.

Switching color formats in the Pixel Comparison inspector, showing different representations of the same color.

In case color spaces don’t match between images, you may see converted values (with the original values as displayed in parentheses).

Locking pixels and comparing positions

Sometimes you may want to keep a specific pixel in focus. Lock the current pixel using one of several methods: double-click on either image, use the keyboard shortcut ⇧⌘L (menu command View > Lock Pixel Sample), or that command from the context menu. Use a single click, the lock icon in the bottom toolbar, or any of the menu options, to unlock the sample again.

In Two-Up view, or when sampling is locked, Kaleidoscope highlights the sampled coordinates in both images with a clearly visible crosshair. This makes it easy to verify that you’re comparing the exact same location in both images.

Clearly visible crosshairs indicate Locked Pixel Samples.
The bar for the red component (R) on the right shows why the color appears very different between A and B:
the value of **1.417** is way outside the 0…1.0 range of the sRGB color space.

Fits your workflow

The Pixel Comparison is a very powerful addition, but it’s still optional, as you may not need it (all the time). A new setting in Settings > Images lets you control whether Pixel Comparison should be shown by default when opening an Image Comparison.

Available now

Kaleidoscope 6.5 is out now, get via Software Update. If you’re new to Kaleidoscope, download the Free Trial. If you have feedback on the new Pixel Comparison or any other feature, we’re always here to listen.

Your work depends on understanding image differences down to the smallest detail? The new Pixel Comparison gives you a clear answer to the question: what exactly changed in those pixels?