Kuuvik Capture 3.3 : Block Artifact Reduction

When displaying RAW files, Kuuvik Capture uses the preview JPG embedded into the file. Unfortunately, these preview JPGs aren’t the highest quality – cameras try to save space by lowering JPG compression quality. The downside is that when one sharpens such an image, 8×8 pixel JPG compression block boundaries may become visible, as you can see on the magnified image below. It is especially distracting on large homogenous dark and light surfaces, and makes judging image quality a harder task.

JPEG compression block artifacts

To combat this, Kuuvik Capture 3.3 introduces a new function, block boundary artifact reduction. Let’s see first what it does.

Block artifact reduction active

Most of the artifacts are gone. Of course permanent damage done by low quality JPEG compression can’t be reversed completely, but the magnified image is certainly less problematic this way.

The function is active by default, but can be turned off in Preferences if you don’t need it. Yes, there are situations, like hard straight edges in architecture and product photography, where the reduction might introduce its own artifacts. It is a tool useful in most situations, and not useful in some. Use it accordingly.

When turned on, the function activates for RAW files between 75% and 100% zoom levels and if sharpening is also active – block boundaries are eliminated by the interpolation process, and not visible at all when you zoom out. It is automatically disabled for JPG files and live view.

Kuuvik Capture 3.3 is available now on the Mac App Store. It is a free update for users who purchased the app from there. You can see the complete list of new features and changes in the release notes.

Kuuvik Capture 3.3 : Clipping Warnings

Version 3.3 is an important milestone in Kuuvik Capture‘s history. It replaces the Apple-provided display processing frameworks – which continuously entertained me with serious bugs over the years – with my own code. And as it usually happens when I put my stuff in place of some dependency, it’s significantly faster, more reliable and opens up new possibilities. This post is about one of those new possibilities.

The app had RAW-based clipping warnings from the very beginning. Multi-level warnings that get stronger as more channels are clipped were introduced in version 2.4. And now clipping warnings based on processed (JPEG) data join Kuuvik Capture’s exposure evaluation toolset.

RAW and Processed clipping warning layers

Processed clipping warnings are also multi-level. And they are available during live view and movie recording. Just keep in mind that exposure simulation should be enabled on the camera for the best results (otherwise live view will not reflect your current exposure).

RAW and processed layers can be shown separately or combined. When used together, the processed layer usually triggers first, just like I showed that in my post about the Dual Histogram. To be able to distinguish the two types when used together, you can choose from different color themes for the processed warning layers (RAW layers are always red/blue).

Menu items controlling warning layers.

There are a bunch of items added to the View menu, as well as to the image’s right-click context menu and to the histogram’s context menu. You can toggle each of the four layers separately, or turn the whole stack on and off with the Clipping Warnings command (or by pressing the W key) when the warnings get in the way of evaluating composition. A new toolbar button is also added for the complete layer stack toggle.

Prefer RAW disables processed layers when RAW data is available for an image. My preferred way of working is to turn Prefer RAW on and set processed warnings to the red/blue theme. This way I always have red/blue warnings: processed ones during live view and for JPG files, and RAW ones for RAW files.

The new display engine also allowed me to reduce aliasing in the RAW shadow clipping warning layer – no more eye straining checkerboard patterns.

Kuuvik Capture 3.3 is available now on the Mac App Store. It is a free update for users who purchased the app from there. You can see the complete list of new features and changes in the release notes.

Kuuvik Capture 3.2 : Other New Features

The Dual Histogram and JPG enhancements were discussed in my previous posts, but there are a few other noteworthy additions in Kuuvik Capture 3.2. Let’s see them!

Camera support

First the new cameras. The Canon EOS 6D Mark II and the 200D/Rebel SL2/Kiss X9 are completely supported. Either using USB or via their built-in Wi-Fi. From the older bunch, we’ve added the 1300D/Rebel T6/Kiss X80, as this camera is quite popular among our photomicrography users. We’ve also continued the rollout of multi-point live view and movie recording support. This time adding the 7D, 750D/Rebel T6i/Kiss X8i, 760D/Rebel T6s/8000D and 1200D/Rebel T5/Kiss X70.

Preferred editor

This was also high on the feature request list. The preferred editor is the RAW converter of your choice that you would like to use to quickly open any image from Kuuvik Capture. By pressing Cmd+E (or via the menus, but I bet that the keyboard shortcut will be used more often).

You can designate any app that is registered as an editor for CR2 or JPG files on your Mac as the preferred editor in Preferences.

For me it’s Capture One, but Photoshop is what several people will undoubtedly use. As Lightroom is not registered as an editor, and is unable to open individual files without importing, you will not see it listed. If you use Lightroom, a hot folder should be set up in Lightroom for the Kuuvik Capture session folder, and it will automatically import images from there.

Drag & Drop

This is a huge time saver. I’m opening my previous shoots with Kuuvik Capture a lot, and going through File > Open Session was always a bit tedious. Now you can drag & drop any folder to the app (even to the icon on the Dock) and the app will immediately open it as a session. Simple and effective.

Under the hood

A lot of things are going on under the hood these days. I’ve mentioned updates to the JPG processing engine with huge performance gains in the Dual Histogram post. The Image Browser also got faster, more efficient, and now uses the image’s EXIF date/time when sorting by capture date (instead of the file’s date).

This release sees the first version of our new display engine. It enables the app to work on macOS 10.13 High Sierra, and also works around an acute NVidia display driver problem introduced in macOS 10.12. If you got an empty screen with 5DS/R files on your MacBook Pro you know what I’m talking about. It also paves the way for some pretty neat features coming in the near future.


Kuuvik Capture 3.2 is available now on the Mac App Store. It is a free update for users who purchased Kuuvik Capture from there. I’m also working on an update to my free eBook, Kuuvik Capture Inside Out, which will be available shortly.

For the complete list of new features and fixes, please refer to the release notes.

Kuuvik Capture 3.2 : JPG Enhancements

Kuuvik Capture was originally developed to foster a RAW-only workflow. But we received numerous requests for supporting JPG files. At first we introduced a RAW+JPG capture option (where JPG files remained on the memory card), and now in version 3.2 you can shoot as well as download JPG files alone. Capture preferences were changed to reflect this functionality.

Image quality controls whether you shoot RAW, RAW+JPG or a new choice, JPG. JPG files are large/fine ones, since we still want to keep image quality at the highest possible level. When you choose RAW+JPG, an option appears so that you can set whether the JPG files will remain on the card (by default), or downloaded along the RAWs. With the JPG image quality setting files are always downloaded of course.

There’s also a new option to force the native 3:2 image aspect ratio. We’ve added this because aspect ratio control is a complete mess on Canons. You have two settings to cope with, and sometimes get a cropped JPG file and other times a full resolution JPG with metadata to indicate the crop. To make things worse, RAW converters and Photoshop tend to change how they interpret cropping metadata from version to version. We simply don’t want to get involved in this messy situation. So by default Kuuvik Capture forces the camera default 3:2 aspect for all images. You have the option to turn it off, if you really really know what you are doing and need non-3:2 images. But you were warned.

Downloaded RAW+JPG pairs will be handled as a single package, but only the RAW file is used for display. Thumbnails in the Image Browser are marked with a “+” badge to indicate that a JPG is also present, while the file name will show just the RAW.

Deleting the package will delete both the RAW and the JPG.

For RAW+JPG (since the RAW is used for display) the Dual Histogram shows both RAW and processed data. For single JPGs only the processed histogram is available.

A bonus feature

Since a JPG is a JPG, you can use Kuuvik Capture to cull JPG images from any source. For example Agnes went through the majority of our family photo collection during the last few months with the app. This included everything from scanned images through iPhone photos to RAWs. Moreover, JPG previews are displayed from older Canon CR2 files (such as those from the 5D and 1D Mark II), as well as from Nikon NEF and Pentax DNG and PEF files produced by Nikon and Pentax cameras supported by our ShutterCount app. Yes, they share the same image decoder.

IMPORTANT: This is a bonus feature that may work for you, but not officially supported.


Kuuvik Capture 3.2 is available now on the Mac App Store. It is a free update for users who purchased Kuuvik Capture from the Mac App Store. I’m also working on an update to my free eBook, Kuuvik Capture Inside Out, which will be available shortly.