Inspiring

Question

How to convert or rasterize AI subject / sky mask?

Forum|Forum|4 years ago
November 28, 2021
6 replies
1438 views

I work with bracketed images. I created an AI subject or sky mask for one of the bracketed images. Now I want to copy and paste this mask to the other images in the bracketed series, but I get a warning that the AI has to recompute the mask. This would be very bad since the bracketed images will be further processed in another software for an HDR effect, and if the AI computes the mask differently for each bracket, then this will ruin the HDR processing.

I want to be able to convert the AI mask into a static, fixed, rasterized, mask so that I can copy the exact same mask to the other images. How can I do this, other than to skip the AI mask and draw it manually with the brush tool?

Windows

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GoldingD

Legend

Clarify this for us.

Are you correcting all the frames in your bracket before stitching them in your HDR software?

Correcting exposure, etc?

If do, that is amazingly wrong. utterly useless.

Also, if you have one or two frames in your bracket that are so far out of exposure, that they pile way up on the left or right in the histogram, with little usable data, then they should be excluded from the bracket, they are of no value to the process.

some exemplers might help, we may be misreading what youor workflow is.

S

sdinweoinasd9384152Author

Inspiring

I really don't understand what you mean that what I'm doing is utterly useless.

How is it useless to adjust exposure before exporting RAW to TIF?

The HDR software inputs TIF or JPG. If the RAW isn't adjusted before exporting to TIF, then the TIF will be clipped in the wrong places.

The window from the interior is only 10% to 20% of some of the panorama points. I am adjusting the exposure for the interior because the windows are less important than the interior. The bright windows will be clipped in the 2 longest exposures in the bracket series because the difference in light is extreme compared to the dark interior. The bracket range cannot be increased because of the workflow.

Are you saying that this is utterly useless work, so then I should simply not take the photo and abandon the work? Or should I simply not shoot the bracket towards the window and not be able to stitch a complete panorama?

J

Jao vdL

Community Expert

> How is it useless to adjust exposure before exporting RAW to TIF?

You shouldn't be increasing the exposure slider on any raw file. The only thing you should worry about is blowing out highlight elements. DO NOT worry about clipping on the left side of the histogram. It DOES NOT exist. It is a myth. In digital imaging, all you need to do is not blow out the highlights and make sure the file has enough bit precision to cover the entire dynamic range, which for typically 12 or 14-bit raw originals means 16 bits export. You need to feed your HDR software as close to the actual exposures as possible and not adjust any of them. Using this information and the exposure metadata in the multiple files (which is why you don't want to touch the exposure sliders as you ruin that info!) it can recover the actual luminance of each pixel in your image by fitting the image data in the files from your multiple exposures and obtain a response curve that describes the tiff data. Basically it recovers the tone curves for your raw conversion engine. This allows it to then accurately recover the actual scene info by combining the multiple exposure images using this fitted tone curve and constructing a linear image again. It is best to do this from raw images as they are already linear in luminance so you don't have to do this but it can be done from jpeg/tiff to by the fit I just described but not all HDR software can work from raw. This process goes wrong if you adjust the exposure slider on a subset of the images and your HDR program will come up with luminance values for those images you adjusted that are a stop off which can cause issues in panorama stitching. Worse if you do local edits, the luminance input for those areas in the image is off from what it really is in relation to the rest of the image which can cause blooming artefacts in the final tone mapping from the HDR file.

It is simply best to feed the HDR combining algorithm files that are as close to scene referred as possible. Raw is best (like Lightroom's built-in HDR combining uses) but in absence of that, flatly developed tiff is what you want with certainly no local edits. If you need local edits, do them after the HDR combining step or after the tone mapping steps.

Bob Somrak

Legend

My mistake, I meant his COPY SETTINGS plugin

https://johnrellis.com/lightroom/copysettings.htm

M4 Pro Mac Mini. 48GB

Bob Somrak

Legend

Use John Ellis's ANY CROP plugin. It will do the copy of the Sky/Subject mask without recomputing.

https://johnrellis.com/lightroom/anycrop.htm

M4 Pro Mac Mini. 48GB

Todd Shaner

Legend

"I'm processing thousands of 3 shot brackets for panoramas, and they all need to be shot with exactly the same number of brackets and exposure range for the batch processing in other software to function. I can't increase the bracket range for specific panoramas that need a wider range."

Using the suggested 2 EV Bracket (-2, 0 +2) you can only cover a 4 EV dynamic range without highlight clipping. I highly suggest you download the RawDigger free trial and check the lowest exposure image file in the bracket sets that require more adjustment. You will most likely find they contain significant highlight clipping in the brighteset areas (i.e. windows). Clipped highlights are not recoverable using any software. Also why must the bracket sets have the same number of brackets and exposure range? LrC can batch Photo Merge HDR without these restrictions. What HDR app are you using?

Just out of curiosity I tried Select Sky on a number interior shots that have bright windows. In almost every case 'No Sky Detected' or only a very small window area was selected. The Select Sky AI clearly isn't designed for detecting bright windows. Have you actually used this succesfully with a number of different bracket sets?

S

sdinweoinasd9384152Author

Inspiring

These aren't helpful recommendations. I simply want to copy the same AI mask to mulitple bracketed images.

As I mentioned earlier, I cannot increase the bracket range because of the workflow. I already know there is clipping in the windows. That is why when a panorama is in front of a window, I simply decrease the exposure in the camera by 1/3 or 2/3 step (compared to the exposure at other places deeper into the interior where the windows are not visible), and the window is captured in the fastest image in the bracket series. Then in Lightroom I increase the exposure by the same 1/3 or 2/3 step that I decreased in the camera. I mask the windows to exclude them from such an increase to preserve them.

Todd Shaner

Legend

"I simply decrease the exposure in the camera by 1/3 or 2/3 step (compared to the exposure at other places deeper into the interior where the windows are not visible), and the window is captured in the fastest image in the bracket series."

In most cases the windows will be much brighter than 1/3 to 2/3 EV. You are working blind and not following my suggestions. LrC and PS/ACR apply a camera profile to the image data making it impossible to determine the actual raw data.clipping in those apps. Please download RawDigger and examine some of those bracket sets that required unerexposure. This is the only way to determine if there is raw data highlight clipping, which is not recoverable. What you should be doing for those lighting conditions is to shoot a five bracket set (-4, -2, 0, +2, +4). Your HDR app should be able to batch process both three bracket and five bracket sets with no issues. If not then I suggest you look for an HDR app that can. LrC can do this type of batch processing using Auto-Stack By Capture Time and then CTRL + SHIFT + H keys to start the batch process.

Todd Shaner

Legend

"I'm masking windows of an interior room to bring the highlights down. If I do not do this to the RAW bracketed images before exporting to TIF from Lightroom, then the windows are completely blown out in the HDR output file from the other software."

If the bracket set was properly shot there should be no need to edit the raw files before exporting to TIFF for editing in the external HDR app. By that I mean the lowest exposure image file should have no clipped highlights with no adjustments inside LrC. If that's not the case then you need to shoot a wider bracket that includes lower exposure image files. You can use RawDigger free trial to check for highlight and shadow clipping in your raw file bracket set.

https://www.rawdigger.com/download

S

sdinweoinasd9384152Author

Inspiring

I'm processing thousands of 3 shot brackets for panoramas, and they all need to be shot with exactly the same number of brackets and exposure range for the batch processing in other software to function. I can't increase the bracket range for specific panoramas that need a wider range. Some of the images are from very dark interiors with an extremely sunny window. I have to expose for the interior, and I already know that only the image with the fastest exposure in the bracket will capture some detail from the window. The other 2 images in the bracket will be blown out.

Since I know about the blow out, I'm lowering the expsoure for the entire bracket to preserve as much detail as possible, then increasing the exposure in Lightroom, but I have to mask the window to exlude that increase to preserve the window.

I simply want to copy the exact same mask of the window to all 3 shots in the bracket. The Lightroom AI mask recomputes for each image, resulting in different masks. The John Rellis plugin might do this, as a short term solution if I want to use the AI mask, as I don't see any other way to do it other than to not use the AI.

Lasso + feathering tool for masking would also really help for geometric masks, which was probably requested for since forever.

J

Jao vdL

Community Expert

"Since I know about the blow out, I'm lowering the expsoure for the entire bracket to preserve as much detail as possible, then increasing the exposure in Lightroom, but I have to mask the window to exlude that increase to preserve the window."

Your problem is in bold. You should simply NOT increase the exposure in Lightroom but just export the brackets directly and merge those (dark looking except for the windows) images in your HDR software. Your final image will come out looking fine. You might even want to dial in a low contrast profile such as camera neutral to help your HDR software but usually it can deal with whatever tone curve was applied. You DO NOT EVER want to apply local edits to bracketed shots that go into HDR merging.

Todd Shaner

Legend

Simply apply the Select Sky mask and settings to the HDR output file from the other app. No need to apply it to the bracketed image files. In fact doing so restricts you post editing options inside LrC for the sky.

S

sdinweoinasd9384152Author

Inspiring

Sorry, but that doesn't help with what I'm trying to do.

I want to apply the same mask to each bracketed raw file before exporting them to TIF and then do the HDR process with the TIF files in the other software.

I'm masking windows of an interior room to bring the highlights down. If I do not do this to the RAW bracketed images before exporting to TIF from Lightroom, then the windows are completely blown out in the HDR output file from the other software. Importing the output file back into Lightroom and then applying the mask afterwards will not save the details in the window, as the details in the window are already lost.

How can I convert the Lightroom AI mask into a static, fixed, rasterized mask so that I can copy the exact same mask to the other images in the bracket series?

Thanks

S

sdinweoinasd9384152Author

Inspiring

Also, this does not necessarily have to be only for interior windows. It could be for any type of image where masking is needed for saving or editing details in bracketed images for export to another software for HDR processing.

Lightroom does a good job of noise / CA reduction to raw files, before exporting to other software for further editing.

Not being able to apply the same Lightorom AI generated mask to other bracketed images makes the tool unusable.

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