32-bit HDR Myths and Methods

32 Bit  HDR Myths and Methods

A funny thing happened a couple years ago with the introduction of Lightroom 4.1. I started seeing people talking about NOW processing their HDRs in 32-bit. Now while it was true that something new happened – 32 Bit Tiff support for both Adobe Lightroom 4.1and ACR 7.1- many people seemed to think that 32-bit processing in any program was not possible before this and even the confusion that Lightroom and Photoshop ACR  (Adobe Camera RAW) were the ONLY programs that did work in 32-bit (Color Bit depth), which simply wasn’t true. All the Major HDR Programs do their processing in 32-bit, Photomatix Pro, Nik by Google HDR Efex Pro 2, Oloneo all of them work in 32 bit depth while in their Tonemapping/processing modules. Period

So, I kinda just left it alone, figured everyone would figure it out after the hype but then I found 2 years later after talking to people and watching a few HDR Workflow videos that people hadn’t figured it out and worse than that, really weren’t sure when they were working with a 32-Bit image.

I thought I would write this article to clear up a few things and also to give a few ways that you can work in 32-bit, How you can make a 32-bit file and the types supported and what is best to do while in 32-bit and when it’s time to call it quits and begin your final processing in other bit depths (16-bit, 8-bit)

Types of 32 bit files

There are 3 general types of 32-bit files or file types that you can save 32-bit in.

32 bit Floating Point Tiff. This is the most commonly used type and  the only type that Lightroom and ACR will work on, although Photoshop itself can open/save other types

Radiance RGBE32 bit (.hdr) Photomatix Pro,  and Photoshop (Not ACR) can open/save as this file type. HDR Efex Pro2  can Open this type (see later notes)

OpenEXR: Photomatix Pro  and Photoshop (Not ACR) can open/save as this file type

There are some technical differences in the 3 file types. The differences only come into play if you can use a file type or not so I won’t go into the differences here since it may all be moot but you can do a search if it interests you

32 Bit File Compatibility

Lightroom: 32 Bit Floating Point Tiff only

Photoshop ACR: In Native ACR mode: 32 Bit Floating Point Tiff only. You can only access the 32 Bit file by using Mini-Bridge (File>Browse in Mini-Bridge) and then right clicking the file and say “Open in Camera RAW”

Photoshop, 32 Bit Tiff, Radiance.hdr, Open Exr: Open/Save directly: In Photoshop CC only; you can access ACR by using the Filter> Camera RAW Filter

Photomatix Pro: 32 Bit Tiff, Radiance.hdr, Open Exr:  Open/Save directly. 

Nik by Google HDR Efex Pro 2: Post the Google take-over suite version; you cannot open a file launching HDR Efex Pro2. Versions prior to that if you didn’t update can open: 32 Bit Tiff, Radiance, Open Exr Directly. The workaround for this if you have Photoshop is to open any of the 3 file formats in Photoshop and then go to Filter> Nik> HDR Efex Pro 2. 

Creating a 32 bit file

If you are already using one of the major HDR Programs, you don’t really have to do anything; your normal workflow creates a 32 bit file with which to work on the tone-mapping processing. But you may want to work on the file in different programs while still in 32 bit and that isn’t always so easy since most programs output in either 16 or 8-bit, yes even Lightroom and Photoshop ACR will do this if you are not careful.

Photomatix: You can create a 32-bit file by using Photomatix as a stand alone. Open the program and click on the “Load Bracketed Photos” Navigate to your Files by hitting browse and select them and then the important step is to: Check the box for “Show 32-bit unprocessed image  ”Photomatix will go through the normal Merge process but then stop at a point when the 32-Bit image is established but before Tone-mapping. It is at this point that you will make your 32 Bit File in your choice of the above 3 and go up to and Save the File as a 32 Bit format Do NOT go on to Tonemapping In Photomatix.

If you have made any adjustments to your RAW Images in Lightroom or ACR, those changes will not be usable in this method as Photomatix does not read XMPs. So you must make Tiffs or Jpegs (16-bit Tiff preferred) with the LR Edit prior to the merge in this method

Photomatix Via Lightroom:Prior to Photomatix  Pro 5 this was also an Option on export from Lightroom. HDRSoft removed this option in Pro 5 but offered a new Method, their Merge to 32 Bit Lightroom Plug in. The advantage of this is you can do all your selecting of images in your Lightroom Library, Then add develop settings (White Balance, Len correction etc) and then Merge the file in Photomatix using it’s great merging and deghosting and then bring the Merged file back into Lightroom as a 32 Bit Floating Point Tiff but without any of Photomatix’s Tone Mapping.

Lightroom: You can not make a 32 Bit file directly in Lightroom alone. You much use either the Photomatix Methods above or the Photoshop Methods below

Photoshop: There are two main ways to make a 32 Bit file in using Photoshop.

From Lightroom: Select your exposures, right click and choose: Edit in: Merge to HDR Pro in Photoshop. When the Merge dialog comes up make sure that the dropdown in the upper right is set to 32 bit. When the Image is merged, click save and the image will come back to Lightroom as a Tiff where you can then Develop/Tone-Map/Edit the 32-Bit

From Bridge: Select your Exposures go up to Tools>Photoshop> Merge to HDR Pro. Again when the merge dialog comes up make sure it is set to 32 Bit. From here you can work on the file in Photoshop using the Limited 32bit tools and adjustments available. In Photoshop CC you have the option of going right to The Camera RAW Filter. Otherwise to use ACR, save the 32bit as a Tiff and then re-open the image in Mini-Bridge, right click and select Edit in Camera RAW. You also in Photoshop CC can make Camera RAW a Smart Filter by first clicking under the filter menu, Convert for Smart Filter and then clicking on Camera RAW Filter (in case it doesn’t make it a Smart Filter by default)

Nik by Google HDR Efex Pro 2/ Photoshop CS6 and earlier with this combination of programs you can also create a 32 Bit File. It doesn’t seem to work for me with Photoshop CC although it may be a Nik Installation problem with CC so your results may vary.

How you get to a 32 Bit file  is to have HDR Efex Pro 2 open as a Smart Object in Photoshop. Select your exposures in Bridge, Then go to Tools> Google >Merge To HDR Efex Pro 2. In the first dialog that comes up for HEP2, there is a check box for “Create Smart Object” It then will continue with Merging and De-Ghosting and then you can if you choose to add tone mapping in HEP2 (some is applied by default) and once you hit OK the image will then open in Photoshop as a 32 Bit File with a Smart Filter Layer with HEP2. This allows for Non destructive editing and the ability to go back to HEP2 for further editing changes and refinements. From There you can save the File in the 32 Bit Format of your Choice, just remember the Smart Filter will not carry over to every other program you may open that file in.

Confusion and Problems

OK so are you confused enough? I’ll take it to the next level of confusion. Working with a 32-bit file is a good thing for the initial stages of making your HDR. However trying to stay in 32-bit or work on a 32-bit image across multiple platforms is where the confusion and problems come in.

Previews

The first major problem we come across are Previews.  32-bit images are not viewable on our Computer Monitors – Interestingly the only time you get to see what a 32 Bit image really looks like is when you merge in Photomatix and stop at the 32 Bit Image to save it, there you get to see really how much range there is in the image and why they are not viewable.

Photomatix True 32 bit Display

But getting back, since the 32-bit file is not viewable, all programs Tone Map the image down to 16/8 bits to be viewable on your Monitor. Yes, this is Tone –Mapping before you even touch a control. Anytime you convert from one Bit Depth to another that is Tone-mapping. Even when your camera creates an in Camera Jpeg, Tone-mapping is done to take the image from the sensor’s 12-14 bits down to 8 bit.

So a Preview is created to make our 32 viewable. The problem is almost NONE of the previews are the same and the preview will figure into the final image once we do finally convert from 32 bit to 16 or 8 bit final image.

These are 4 preview generated from the same 32-bit Tiff using different programs (Before edit tone-mapping)

Photoshop 32 bit Preview

Lightroom 32 Bit Preview

Photomatix Pro 32 Bit Preview

HDR Efex Pro2 32 Bit Preview

It’s understandable that different brand software will render the preview differently. But something little known is that even among Adobe Products it is rendered differently. In Lightroom and ACR, a floating bit image is rendered using “Scene-Referred with Linear Gamma” Photoshop outside of ACR renders with Monitor Gamma (I may not be perfectly correct in this statement so correct if you know better) so the two Look VERY different. You can go back and forth between Lightroom and ACR and have the image look the same (Not sure why you would need to) but when that same 32 Bit Tiff is open in Photoshop itself, it looks very different.

The Preview in Lightroom and ACR is not adjustable. However in Photoshop, you can change how the image is previewed. Go to View>32-bit Preview Options.  If you wish to get the two to look similar you may want to try adjusting the 32 Bit preview in Photoshop to +1.0 stop exposure and pull the Gamma down to 1.2. This will get it closer but still not exactly the same (There seem to be some color balance differences too) your results may vary.

32 Bit Preview Options

Also, don’t think just because a program previews differently that it necessarily is better then another. Just be aware it happens.

Compatibility in Editing across platforms

This applies to only as long as the image remains in 32-bit and many times people are not still in 32-bit even though they assume they are.

Lightroom to ACR

Compatibility: High.  Make sure you have Lightroom set to also write develop settings to XMP sidecars and not just to the catalog. Changes made in Lightroom will be visible in that 32-Bit Tiff when opened directly in ACR and vice-versa. Just make sure if you are working in ACR and you are finished editing you click done and not open. Open, opens the image in Photoshop but also reduces the image to 16/8 bit depending on how you have ACR set. If you want to go back and forth between LR and ACR just hit done…although I’m still not certain why you would want to given that they do the same thing.

Lightroom/ACR to Photoshop

Compatibility: None. Make sure you understand clearly what I am saying here. This is purely with the 32-bit file. It’s taking a 32-but Tiff, making changes in the LR develop module. closing Lightroom and then opening that 32-bit directly from Photoshop/Bridge. This is NOT right clicking the image and saying “Edit in Photoshop” or Clicking Open in ACR. Doing so will apply the develop settings BUT it will export the image into Photoshop as a 16/8bit image. It is a new image and NOT the 32-bit. So changes you make to a 32-bit Tiff in Lightrrom/ACR will not carry over to Photoshop.

Opening the 32-bit in Photoshop, even though Lightroom is supposed to write those changes to within the Meta of the Tiff even if you push the Meta it is not read by Photoshop and you will not see the Lightroom edits you applied in the develop module

Lightroom/ACR to Photomatix/ Nik HDR Efex Pro 2

Compatibility: None. Again let me make it perfectly clear. This is opening the file directly in these programs, they do not read XMP or Embedded catalog settings so they will not show any edits done in Lightroom or ACR. This is NOT right clicking a Single 32-Bit Tiff in Lightroom and saying “Export to HDR Efex Pro 2/Photomatix Pro” That command will again drop the bit depth to 16/8- Bits depending on your export settings. It’s not working on the 32 Bit file from that method. This is about opening these programs as stand-alones and then opening the 32-bit Tiff, It will not show the LR/ACR edits

Photoshop to Lightroom/ACR Changes made to and saved to a 32-bit Floating Point Tiff in Photoshop will be visible in Lightroom/ACR…HOWEVER because of the differences in Preview between how Photoshop Previews and how Lightroom/ACR Previews, the image almost becomes useless to try and do other editing in Lightroom post working in Photoshop so you really need to watch your workflow here and again I would recommend upgrading to Photoshop CC so you can access the ACR filter from within Photoshop and then do ALL your work within Photoshop
*Edit/Update 6/17/2014* in doing some testing today, I found that while there are some difference in preview rendering, a bigger problem I found was Lightroom Double Processing the Photoshop  image. I will post a separate post about this odd occurrence

How do I know if I am in 32-bit?

Even knowing when you still have a 32 Bit file can be difficult to know. Photoshop does the best job of showing it. In the Image tab that shows the Image Name in the last part of that it shows the Color Mode and Bit Depth.(See the header of the Photoshop Preview image above) You can also Check under Image> Mode for the bit depth the image is in (This is also where you would go to change the Bit Depth when you desire, if it doesn’t happen in some of your other editing workflow such as Export in Lightroom etc). You can  see the Bit Depth of an Image in Bridge in the Metadata panel. In Lightroom I couldn’t find any place that showed the Bit depth of the file, maybe you’ll have better luck.

Working 32-bits is Hard…sometimes

As you can see, while Tone-mapping developing in 32-bit is necessary AND a good thing because you can take advantage of the extra information you may have captured. You can see that trying to work cross platforms is extremely difficult if your goal is to keep the image as long as possible in 32-bit. But the truth of the matter is after a certain point it really is no longer necessary to work in 32-bit and you may be better off not being in 32-bit.

Do all your heavy lifting in 32-bit especially any exposure/highlight/shadow work. That is where the virtues of 32-bit are the best. Once you have as much of that work done as possible then really it’s not a bad thing to convert to 16-bit and continue on with your editing. Since at that point the image is no longer a High Dynamic Range image but rather a standard DR Image (hopefully not Low DR , said with a smile) so don’t sweat not being in 32-bit

All of the major filter and plug-in; Topaz Labs, Nik, onOne etc do not operate in 32-bit color mode so you must be in 16/8bit.  Only about ¼ of all the tools/image adjustments and filters in Photoshop will work in 32-bit so even there, there is just so much you can do

Programs like PTGui, while it can Output a 32-bit really can’t do anything with it after you work on the image in LR/ACR because it doesn’t recognize the XMP

So find a workflow that works for you and stop sweating it but be aware of it.

Complex

If you really want to be able to do the most work in 32-bit, the best workflow would be entirely within Photoshop CC (not ACR) because CC is able to access ACR as a smart Filter.

Photoshop Raw Filter

You can do those edits and then do whatever else Photoshop has the capability of doing in 32-bit. But even at that at some point you will need to convert to 16-bit and move on. If you have been hesitant to get in on Photoshop CC for one reason or another, the capability it has to go to the RAW Filter is the best reason to have it

A workflow I will use sometimes when I need the great merging/deghosting power of Photomatix on a difficult to merge image (handheld, lots of tree branches etc) is to Open Photomatix, Open my RAW files from there, click the 32-Bit Preview box, Merge the image and then when the 32-bit pops up save as a 32-Bit file. Then I open that file in Photoshop CC, work it in the Camera RAW filter, make as many adjustments as possible or needed while a 32-bit and then finally convert it to 16-bit (using Image>Mode>16bit which will bring up the HDR Pro interface and then drop it down to Exposure/Gamma and click OK unless you want to use the HDR Pro tone-mapping- I don’t)

When it’s 16-bit I use all the other tools and filters and everything that is now available and then save that file as a new Master 16-Bit file with Layers Intact. But that’s me. Find what works for you

Simplicity

The other main method I use and a lot of people find good is using The HDRsoft’s Merge to 32 Bit Plug-in with Lightroom It works just Great and gives a fast and easy workflow which in the end may be all you need or even the best method.

With that method and without Photoshop being necessary you can select your images in Lightroom, Right Click and Merge to 32 Bit. After the merge the image auto re-imports to Lightroom. Do all your heavy lifting in the Develop Module and then if you want to use 3^Rd Party Plug-ins; Topaz, Nik; onOne etc – do so at the last point because Lightroom will now convert it to a 16-bit image and you can finish up your HDR Image. This is the best and most painless workflow and one I use very often.

If you would like to Order HDRSoft’s Merge to 32-Bit Lightroom Plug-in Click this link and enter the Coupon Code THEHDRIMAGE for 15% off your order

OR…simply continue with your current workflow. Like I said at the beginning of this, when you are using a normal Photomatix Pro or HDR Efex Pro 2 workflow you are still working the image in 32-bit while in the Tone-mapping/Fusion Modules so maybe even making a 32Bit Tiff is a waste of time if you are happy with the results you are getting currently. Making a 32-bit Tiff may open up some options for different looks but it may not give you the end result you want or achieve using a more standard workflow for HDR. But hopefully now you will have a better understanding of what people are saying when they say “32-bit HDR” it may not be anything different then what you already had.