Essential HDR, the Revolutionary HDR Tonemapping Software from Imaging Luminary, LLC

How to Use This Page.

Beginners to HDR tone mapping should start with the section headed Introduction to HDR Tonemapping.

For experienced photographers, check out the Essential HDR™ User Manual or the Useful Links section.

In the Advanced Topics Section we will discuss concepts and issues in a broader context and discuss how Essential HDR is used to solve related problems. This section is for the curious.
The FAQ Section will be constantly updated as the software evolves. Please contact us if you have any comments.

Notices and trademark information

No part of this document may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language in any form, by any means, without Imaging Luminary LLC.’s prior written permission. Imaging Luminary LLC. reserves the right to change the specifications of the hardware and software described in these manuals at any time and without any prior notice. Imaging Luminary LLC. will not be held liable for any damages resulting from the use of this product. © 2008 Imaging Luminary LLC., All Rights Reserved.

EssentialHDR, the Essential HDR application icon, Imaging Luminary logo, Fast Tone Balancer, Detail Revealer are trademarks of Imaging Luminary LLC. Microsoft and Windows are registered trademarks of Microsoft Corporation. Intel, Pentium, Xeon, and Core are either trademarks or registered trademarks of Intel Corporation. All other trade names mentioned in this document or in the other documentation provided with your Imaging Luminary LLC. products are trademarks or registered trademarks of their respective holders.

Useful Links

HDRI Community Forum on HDRLabs.com is a highly recommended discussion board on a broad range of topics.

Essential HDR discussion group on Flickr.com is not directly affiliated with the company.

The Work from Professional Photographer Mark Simms who successfully and skillfully integrated HDR Tonemapping into his daily workflow.

Introduction to HDR Tone Mapping

High Dynamic Range(HDR) Photography is the process of creating images in which the ratio between the maximum and minimum measurable light levels are higher than can normally be achieved during a single photographic exposure. In simple terms that means creating photographs contains more brightness levels than usual. These extra brightness levels are usually used to allow detail that would normally be lost in pure black shadows or pure white highlights to be retained, thereby producing photographs which more closely resemble the world as humans normally see it than can be captured by a camera.

HDR images cannot be created in a single exposure by currently available digital cameras, so they have to be assembled from multiple exposures instead. A typical method is to take three shots of the same scene, each shot using a different exposure. For example: one normally exposed shot, one shot under-exposed by two stops and one over-exposed by two stops. In photographic terms these exposures would be described as: 0EV, -2EV and +2EV (EV stands for Exposure Value). The three images are then combined by computer software which draws on the over-exposed image for the scene's shadow details, the normally-exposed image for its mid-tones and the under-exposed image for highlight details. Most modern digital cameras have an automatic exposure bracketing (AEB) feature that is ideally suited to this purpose, allowing multiple exposures to be made with a single press on the shutter release button.

Once created, HDR images cannot be displayed directly on a computer monitor or television as these devices don't have a sufficiently high dynamic range. Instead, HDR Tone Mapping must be applied to the image to transform it into an image with a normal dynamic range.

Tone mapping technology is the most critical step in HDR Photography and Imaging Luminary has invented two revolutionary tone mapping algorithms, Detail Revealer™ and Fast Tone Balancer™ , which are now available in the company's first software product: Essential HDR™ .

The trial version, known as the Community Edition, can be downloaded free of charge. Once installed, it can be evaluated quickly by dragging three photos of the same scene, taken at different exposure values, into the main window. Essential HDR™ will merge the photos into one HDR source and, in its default state, run the Fast Tone Balancer™ (FTB) global tone mapping engine using the default settings. The resultant image can then be saved as either a JPEG or 16-bit TIFF file, or exported to third-party photo-editing software. Comparing the program's output with the original photographs it will be evident that the tone mapped HDR image contains the greater level of detail.

Photograph by Kai Fisher

short_ribs@hotmail.com

It's also possible to adjust the settings used by Essential HDR™ and to choose which tone mapping engine to use, of course. Clicking on the "Tone Mapping" button in the top left-hand corner of the window to invoke the tone mapping preview dialog. This allows you to compare the effects of both tone mapping engines on your image and to fine-tune their parameters. Once you have decided which engine to use, and are satisfied with the settings, click on the relevant "OK" button and Essential HDR™ will tone map your image. You can now save the image or export it to your photo editing software.

That's it. You have fully mastered HDR tone mapping with Essential HDR™.

Essential HDR™ User Manual

Introduction

Essential HDR™ is powerful tone mapping software designed to work with the current generation of DSLR cameras. It has a simple, easy to navigate user interface which will help you develop an efficient work-flow. Compared to other HDR tone mapping software, Essential HDR's no nonsense approach saves valuable time and effort. During the development of the software many beta testers provided a great deal of feedback that had a decisive impact on the program's design. We thank the community for its support and will continue the consultative process to deliver effective software that works just the way its users want it to.

To HDR or not to HDR, that is the question - Essential HDR can be used to tone map the following types of images

1. High Dynamic Range (HDR) images. With a dynamic range of about 14EV, these images are usually produced by merging multiple images of different exposures.

2. Medium Dynamic Range (MDR) images. These have a dynamic range of between 9EV and 16EV and can be originate from a single camera RAW file, a 16-bit TIFF file, or by merging two or more JPEG images of different exposures.

3. Low Dynamic Range (LDR) images. These have a dynamic range of around 8EV or lower. This means one JPEG photo.

These are not very strict categories. For example, the popular way of shooting for HDR is to merge three JPEG photos with exposures of -2EV, 0EV, and +2EV. That gives you at most 12EV of dynamic range, roughly equivalent to the dynamic range from one camera RAW file from a modern DSLR. On the other hand, it should also be considered that although manufacturers might claim their cameras produce 14-bit RAW files, some of those bits of data may consist of nothing but sensor noise.

Using Essential HDR to tone map and save modified files generally works best with HDR and MDR images. Photographers generally use Essential HDR for the following purposes:

1. Optimizing tonal range.In traditional photo editing software, this is done through the "curves" feature. Fast Tone BalancerTM automatically applies the optimum curve to the HDR/MDR data to map it to 8-bit RGB output.

2. Revealing more image detail.This is achieved by local tone mapping. Of course, not all local tone mapping methods were created equal and the search for better local tone mapping algorithms is one of the most active research areas in the field of image manipulation. Detail Revealer™ has the following advantages over previously developed local tone mapping methods:

Speed - Detail Revealer can achieve a tone mapping performance of two million pixels per second on modern mainstream PCs.
Scalability - Detail Revealer is optimized for multi-core CPUs and can scale linearly as the number of pixels increases. In other words, its speed doesn't decrease significantly as the images get larger.
Image quality - Detail Revealer is based on a brand new approach to tone mapping which greatly reduces the incidence of artifact production.
Simplicity - One parameter controls the level of detail being revealed.
Consistent results between preview and the full-size image - Detail Revealer is able to deliver consistent results with the same set of parameters even if the source image is resized. You can be confident that what you see in preview mode will be what you get in the full-sized image.

3. Producing special effects. By pushing the tone mapping parameters to the limits, surreal results can be achieved.

System Requirements

32-bit Windows XP SP2 and higher
or Windows Vista SP1 and higher
1GB main memory minimal, 2GB preferred
1.6 GHz CPU at least. Dual-core CPU preferred
Screen resolution: 1024x768 minimum. 1280x1024 preferred

Essential HDR can run on 64-bit Windows XP or Vista. However, our current support effort focuses on 32-bit OS.

Supported Image File Formats

Source image can be in the following formats

Jpeg: 8-bit per channel RGB
BMP: 8-bit per channel RGB
GIF: 8-bit per channel RGB
PNG: 8-bit per channel RGB
TIFF: 16-bit per channel linear RGB
Canon Raw file, *.CRW and *.CR2
Nikon Raw file, *.NEF
Pentax Raw file, *.PEF
Sony-Minolta Raw file, *.ARW and *.MRW
Adobe DNG
Radiance HDR
OpenEXR

Result image can be saved in the following formats

Jpeg: 8-bit per channel RGB
BMP: 8-bit per channel RGB
PNG: 8-bit per channel RGB
TIFF: 8-bit and 16-bit per channel RGB
Radiance HDR

Support information

Feedbacks? Bug report? Post your message on the Product Support Forum

http://www.imagingluminary.org/support/

Running Essential HDR™

Once installed, the application can be launched by double-clicking on the application's desktop icon or entry in the Start menu. This brings up the program's work area, above which four menu option: File; Tools, Window; and Help are displayed.

The File Menu

Align and Merge Multiple Photos: brings up a system file-open dialog that allows multiple JPEG- or RAW-format files to be imported into Essential HDR. The files are then aligned and merged into one HDR image. The HDR image is then saved in the computer memory as an RGB image with 32-bit floating point values per channel format. This highly accurate format is used throughout the process to avoid the accumulation of rounding errors during the tone mapping process.

Merge Multiple Photos w/o Align: will do the same as above except with no alignment.

Open Any Image File: allows single RGBE HDR or OpenEXR files to be opened for processing.

Open Camera Raw File: allows one or more camera RAW files to be opened. If more than one file is opened a merge will occur. One thing to note is that the above commands are not mutually exclusive. There is more than one way of opening one camera raw file, for example. One popular method is to Drag and Drop files from within file management software. Just select the set of images required, drag them onto the main window, then drop. Essential HDR will start processing.

Save Result As: brings up the system save dialog and prompts for a name under which the current tone mapped result will be saved.

Save As HDR File: works as above but saves the 32-bit HDR data to file, rather than the tone mapped data.

Exit: leaves the application.

The Tools Menu

Options: currently the only Tools menu entry, opens the program's options dialog, which contains three tabs:

The General Tab: contains five check boxes:

The first selected controls whether or not EXIF data is read when JPEG files are loaded. If unchecked, exposure values will be estimated from image data. An example of when this should be unchecked is when images with the same exposure but different lighting conditions are being used to create an HDR image.

The second controls mouse movement while zooming. Clicking the left mouse button over an image activates the zoom feature and moving the mouse while zooming allows you to view parts of the image not in the field of view. The default action is for the image to follow the mouse movement but ticking this box changes this behavior, so that the mouse now controls the movement of a view port onto the full-size image.

The third dictates whether or not images are aligned automatically when they are dropped onto the program's work area.

The fourth controls whether or not you are prompted for a value used in a function discussed in the single RAW file part of the Advanced Topics section.

The fifth check box controls whether or not you are asked to confirm the closing of the preview dialog.

The Defaults tab: contains settings which govern the tone mapping method and parameters applied by default to images loaded into the program. Please note that the factory default settings, which can be reset from here, are not always optimal but, rather, compromise setting which usually produce acceptable results.

The Advanced tabsets the default exposure value used when opening single RAW files. See the Advanced Topics section.

The Windows Menu

Provides for the arranging or closing of all open image windows.

The Help Menu

Provides access to program licensing information, this user manual, the Imaging Luminary Web site, the Essential HDR Support Forum and the software About dialogue.

The Image Window Toolbar: Each image window has a toolbar consisting of six buttons.

The Tone Mapping button opens the tone mapping preview dialogs

The Redo/Undo buttons allow the user to step backwards and forwards through the image history.

The Export To button accesses a drop-down list of third-party software to which tone mapped images can be exported. This allows the user to pass an image on to an editing program without having to go through an intermediate file saving step.

The Save Result As button brings up the system file save dialog, where the current image can be saved under a user-defined name in any one of five different file formats: JPEG, BMP, PNG, TIFF or 48-bits/pixel TIFF.

The Show/Hide Info Box button toggles the display of the image's RGB histogram.

The Tone Mapping Preview Dialog Toolbar: each toolbar contains four buttons:

The Vertical/Horizontal buttons dictate whether the engine controls are below (Vertical) or beside (Horizontal) their respective images.

The Single Preview button will hide the right-hand preview if two previews are displayed in Vertical mode or the lower preview if in Horizontal mode. If a single preview is currently displayed the behavior changes and the button switched the preview between Vertical and Horizontal layouts.

The Tone Map Parameter Set button accesses two menu options which allow the current engine parameters to be saved to file or for previously saved parameters to be reloaded.

Advanced Topics

Single RAW file HDR tone mapping

It's questionable whether the dynamic range of a single RAW file is high enough to allow a description of HDR to be used, so it may be more accurate to talk of single RAW file MDR tone mapping. However, with more camera manufacturers offering sensors collecting 14 or more bits of data, single RAW file HDR/MDR tone mapping certainly has a future. Although, in many cases, the noise in single RAW HDR tone mapped images is still high, the advantage of such a method is apparent. In sports photography, for example, where high shutter speeds are used to capture moving subjects, it would only be possible to use single exposures for HDR tone mapping. Without the need to merge and align multiple exposures the whole process suddenly becomes simpler and faster.

Essential HDR has a unique feature which allows the user to change the dynamic range of a single RAW format source image. This feature is especially helpful for night, or other high ISO, shots. Increasing the tone mapping engine's brightness setting can also be useful in these circumstances.

In the examples below (from left to right), the Detail Revealer engine was used with dynamic range set to 10EV, 8EV, 6EV, and 6EV plus setting brightness to 30.

Top: full image; Direct output from Detail Revealer.

Bottom: 100% crop. Direct output from Detail Revealer.

http://www.eyecandyphotographic.co.uk

Tone Mapping Shallow Depth of Field Images

Very low f-stop settings produce images with shallow depth of field. Traditionally this is a tough situation for any local tone mapping software. The out-of-focus area (sometimes known as bokeh http://en.wikipedia.org/wiki/Bokeh ) can be destroyed by aggressive detail-enhancing local tone mappers and artifacts introduced during tone mapping. However, testers have found that if noise is under control (by using a low ISO setting), Essential HDR can produce very good results from images with shallow DoF. Below are some examples from Mark Simms.

http://www.eyecandyphotographic.co.uk

Frequently Asked Questions

Why don't you have feature X in Essential HDR?

Essential HDR is not, and will not become, a general purpose photo editing tool. There are many, far better choices available for general purpose photo editing: Adobe Photoshop; the free tool Paint.net; and GIMP, to name just a few. Essential HDR will never try to compete with them. Instead, we want to create the most effective, and easiest to use, tone mapping software available.

Essential HDR is only one step in your full work flow. In this step you can use Fast Tone Balancer to get a good curve function, or you can use Detail Revealer to obtain more detail. Both tone mapping functions were designed not to introduce any artifacts. They are simple, single-function processors to be used together with other tools in your toolbox.

Take the following as an example; it's evident that a local tone mapper has been used in the process but that other sophisticated post-processing steps have also been taken to produce the final image.

http://www.eyecandyphotographic.co.uk