What is HDR ?
High dynamic Range is the dynamic range between light and dark areas of the image which exceeds the range of human vision range in the real world. Its nature that human vision can only adopt different brightness levels, but most the cameras can capture and produce only fixed dynamic range. All kind of photographers must select what’s important in their scene because they are just working with limited dynamic ranges.
HDR images can represents entire dynamic range of visible world, since this is because all the luminance in real world is represented in proportionally. As an example like adjusting exposure of a HDR is same as adjusting the exposure of real world scene. Today HDR images are mostly used in smartphones like iPhone, android and many other phones. HDR is also used in motion pictures, 3d work and high resolution photography.
HDR Image in Photoshop
In Adobe photoshop, the luminance value of an image is stored as a floating point numbers. The length of each floating number is 32-bits long. Now you should be thinking what is luminance, luminance is the amount of brightness in the image. In case of 16-bit and 8-bit the case is not same as with 32-bit.
How to Create an HDR Image
To create an HDR image same is scene is captured with different exposure. Here one should note to make an HDR image the scene which you are going to capture should be same. Later in photoshop these images are merged to create an HDR image. HDR image when merged crossed the level of brightness which a 24-bit monitors supports thus its not possible to view that image in the monitor but you don’t need to worry about this adobe photoshop handles this matter by adjusting the preview of HDR image, which successfully display HDR image on monitor.
You can also apply filter on HDR image like gaussian filters, some of the filters are supported on HDR images so you will have to convert HDR image into 16-bit or 8-bit depending upon the filter. If you don’t know how to convert follow this tutorial.
How to Merge Multiple Images
Now I am took 3 pictures from my iPhone, I am going to merge the following three pictures in photoshop.
Now to merge above three picture do the follow the following procedure.
- Open Adobe Photoshop version CS6.
- Click on file -> Automate -> Merge to HDR Pro
- See the following screenshot if you unable to find these menus.
Select Images to Merge
- A new window will open from where you can select files to merge.
- Its recommended to take 5-7 picture with different exposure to get fine results, but here I am taking just 3 pictures for the sake of tutorial.
- Now select the images, you also remove the images after selecting, see the following screenshot to understand this situation.
- Also check the ” Attempt to automatically align source images”.
Menu After Merging
- After adding all images click ok, now if you are using it first it would possibly take min to configure these images and also to merge the selected image, depending upon the number of images merged, also depends upon the size you are using.
- After you should see the following form.
Remove ghost Effect
- Now image has a look like ghost, this is because while taking image, hand movement may disturb the camera location little.
- Just click on remove ghost to remove this effect, after then you will see your image will become fine than before it was.
- Now see the screenshot after removing this ghost effect.
Select 32-Bit Mode
- Now select 32-bit mode from the drop down menu appearing down to remove ghost checkbox
- 32-Bit mode automatically adjust the preview of image.
- See the results after selecting 32-bit mode
Use Slider to adjust Histogram
- Now adjust the histogram equalization graph to set the brightness level.
- From bottom left menu you can also select each image to set the histogram.
- See the following results after setting histogram.
- Now press ok, file be start creating.
- Be sure to choose 32-bit mode if you want to store the whole dynamic range of HDR image.
- You should see the following screen after you press ok.
Important Tips & Information
- If you choose 32-bit mode, just move the slider to adjust the histogram, the intensity levels of brightness.
- All images chosen remain in the 32-bit per channel.
- All images are stored as 32-bit and previewed adjustment are also stored in 32-bits per channel HDR, this can be applied again whenever data is opened again in adobe photoshop.
- Any image merged in 8 or 16-bit mode when discarded are unrecoverable.
- Now see the finalized result is an HDR Image.