HDR (short for High Dynamic Range), is a monitor-display technology that can show various types of lights in a picture and highlight details that would otherwise be lost.
To work with HDR in ZPS X, you must have a monitor that supports HDR, and the use of HDR must be turned on in your Windows settings for the given monitor. It is not recommended to use this function unless you have adequate hardware.
Any picture can be edited in HDR, but in general HDR editing is most appropriate for pictures that already contain HDR data before they enter the program. We currently support reading of HDR data for pictures in the JPG, AVIF, and JPEG XL formats. HDR photos can also be exported to these formats. Because RAW files contain a large amount of data, they are also well-suited for HDR editing.
Devices that do not support HDR are called “SDR,” which is short for Standard Dynamic Range. HDR photos typically contain both HDR and SDR content: a portion of what is in a photo can be viewed even on SDR monitors, but another portion is only viewable on HDR monitors.
How HDR Works
In the photography world, the amount of light captured is measured using a unit called EV (exposure value). Put simply, this value expresses the difference between the darkest and lightest point in a photo. The human eye can perceive a range of 15 EV, and a camera can capture 12 EV when shooting to RAW. However, monitors that are limited to standard dynamic range only show a range of 6 EV. HDR monitors can show up to an additional 4 EV, but the number of additional EV can vary. HDR monitors thus display ranges from 6.5 to 10 EV.
In practice this means that when using the HDR feature on a correctly configured HDR monitor, photos’ appearance is closer to how the given scene appears in real life when viewed with the naked eye: any light sources in a photo shines more intensely, and the contrast between light and dark areas is greater. HDR technology can thus show more of the information contained in a picture’s light portions, and in turn also show more details and colors in places that would simply be overexposed with the use of SDR technology. HDR is not an effect that is applied to a photo; it is a different means of interpreting the data contained in the photo.
At the same time, HDR is only justified for photos that are being prepared for presentation in digital form. It is generally not suitable to edit photos in HDR if they have been prepared for printing.
HDR within the ZPS X Environment
The controls for working with HDR are located in two modules: the Manager, and especially Develop. HDR display is not possible in the Editor, Print, or Video modules.
Manager and Develop | 
HDR Display Mode
This button is present in the Preview mode within the Manager and Develop modules. It is located in the topmost of the toolbars under the preview, and it is turned on by default. The button icon signalizes whether the displaying of HDR content is turned on or turned off, or more precisely whether preference will be given to a picture’s HDR variant if available, or whether the picture will always be converted to SDR instead.
Click the arrow button by the HDR icon to view further options:
- Display Mode – Automatic
- Display Mode – Forced SDR
- Brightness Clipping – Clip
- Brightness Clipping – Tone Mapping
- Brightness Clipping – Clip
- HDR Range – Based on Monitor
- HDR Range – Simulate +0 EV
- HDR Range – Simulate +1 EV
- HDR Range – Simulate +2 EV
- HDR Range – Simulate +3 EV
- HDR Range – Simulate +4 EV
Display Mode
The program’s default option here is Automatic. If this option is active, and an already-edited picture with HDR content is open in the preview, the HDR content is displayed automatically.
If the Force SDR option is active, the SDR version of a picture’s content is shown for every picture, even when it has an HDR version.
Brightness Clipping
The clipping options are used for adapting a picture’s display to the current lighting conditions in the user’s environment.
The default option here is Automatic. With the Automatic setting active, the Tone Mapping method is used in the Manager, and the Clip method is used in Develop.
Tone Mapping is generally more useful when bad lighting conditions have forced you to strongly increase your monitor’s Brightness setting. However, we recommend that you only use this mode for viewing photos, not when editing them.
Brightness clipping is more suitable for editing, because in Clip mode, there is no risk of distorting the presentation of a photo’s colors and brightness. If a monitor’s Brightness has been turned up so high that it impacts the brightness range reserved for HDR, the high dynamic range is reduced (clipped) appropriately. However, for best results we recommend editing pictures in suitable lighting conditions that do not demand an excessive increase to monitor brightness.
HDR Range
The default setting here is Based on Monitor, which means that the preview corresponds to the monitor’s brightness range. The remaining options simulate how a photo looks on HDR monitors with a differing luminosity range.
Develop | Color Style | HDR
The HDR button is located in the Color Style section of the right panel in the Develop module. Press this button to activate HDR; these changes will then appear:
- on an actual HDR monitor, the parts of a picture that contain HDR content will become brighter;
- further controls for editing the HDR and SDR versions of a picture are shown in the right panel;
- the HDR Display Mode button is shown if it was not previously active;
- the appearance of the histogram changes;
- an HDR icon is shown in the top part of a photo’s thumbnail.
Develop | right panel | controls for HDR editing
After the HDR button has been activated in the Color Style section, an HDR White slider appears in the Exposure section. An SDR Adjustment section is shown under the Exposure section.
HDR White – shift this right or left to increase or decrease the luminosity of HDR content in a photo.
SDR Adjustment
This section contains a Show Preview checkbox and White Point, Black Point, Lights, Shadows, Whites, Blacks, Lights – Clarity, and Lights – Saturation sliders. Turn on the Show Preview option to open up access to these sliders.
Show Preview – with this option active, a picture’s HDR contents are converted to SDR. This offers a visual control of how your HDR photos are shown on monitors that do not support HDR.
If HDR is turned on, then only the sliders in the SDR Adjustment section affect the appearance of a picture’s SDR version. The slider of the same names in the Exposure section affect both the HDR and SDR versions of a picture.
It is important to note that it only makes sense to use the SDR Adjustment feature in the situation where the resulting picture will be exported to JPG format. The AVIF and JPEG XL formats do not take SDR Adjustment into account, because at present (April 2024), these formats do not support the storing of both a picture’s SDR and HDR versions.
Manager and Filmstrip | file thumbnails | HDR icon
When the HDR function in the Color Style section of the Develop module has been turned on, the [] icon is displayed in the top part of each file’s thumbnail. This icon disappears if the function is turned off. The displaying of this icon cannot be turned on if HDR is turned off.
Export | Format
Pictures that have been adjusted in HDR mode contain both an HDR-file version and an SDR-file version inside them. During export, you must decide how this information will be treated. HDR can be exported to three formats: JPG, AVIF, and JPEG XL. Retaining a picture’s HDR and SDR version in one file is only possible during export to JPG. Only the JPG format takes the settings in the SDR Adjustment section into account.
During export to JPG, the following options are available in the Format | Dynamic Range section:
- Keep High Dynamic Range (HDR) – if the source file contains HDR data, the exported file will contain both an HDR and an SDR version. For the SDR version, the settings in the SDR Adjustment section will be used. If the source file contains only SDR data, the exported file will also contain only SDR data.
- Standard Dynamic Range (SDR) – the exported file will contain SDR data only, without regard to whether or not the source file contained HDR data. This potion is useful, for example, when preparing a photo for printing.
For export to the AVIF and JPEG XL formats, the same set of options is available under Format | Dynamic Range, but it has partially differing effects:
- Keep High Dynamic Range (HDR) – if the source file contains HDR data, the exported file will contain only the HDR version of the picture. The settings used in the SDR Adjustment section will not be taken into account, because these formats do not currently support the saving of an HDR and SDR version of a picture in the same file. If an HDR picture created this way is shown on an SDR monitor, the software that is displaying the file is responsible for its conversion to SDR.
- Standard Dynamic Range – the exported file will contain SDR data only, without regard to whether or not the source file contained HDR data.
For AVIF, an additional option is shown: HDR Color Space, with the options Do Not Change, HDR sRGB, HDR Display P3, and HDR Rec.2020.
Preferences | Advanced
The Develop – Enable HDR adjustments in Develop by default for HDR photos setting determines how the Develop module treats files that are not RAW files and contain HDR data. Three options are available:
Off – files will be edited in standard dynamic range.
On – files will be edited in high dynamic range, which means that the HDR button in the Color Style section in the Develop module will be automatically turned on.
Automatic – files will be edited in high dynamic range if the user has an HDR monitor and the use of HDR has been turned on within the operating system’s settings. If these conditions have not been met, files will be adjusted in standard dynamic range.
Undeveloped SDR files that are not RAW files are always edited in standard dynamic range. Undeveloped RAWs will be adjusted based on the the choice of default setting in the Develop module.