Raw Therapee for DNG infrared image processing


(Mike Myers) #1

I am very new here; until several days ago, I never heard of “Raw Therapee”, and the way I did find you was through a pop-up windows at GIMP, telling me that if I wanted to work on a DNG image, this program needed to be installed. I downloaded and installed Raw Therapee, and started learning how to use it, but I had computer issues so I’m starting over again.

I have owned a Leica M8.2 camera for a little over ten years, and every time I start using this camera again, I get involved in taking infrared photos. Because Leica “forgot” to include an IR blocking filter, this camera is great for capturing IR images. It has a rangefinder/viewfinder, so I don’t need to see through the lens like a DSLR, with the attached deep red filter. The built-in metering system works well, and it’s easy to adjust the focus for IR.

My original goal was do do my editing in Lightroom, and I was struggling to create a custom profile for IR. Then I decided to try GIMP, which had me install Raw Therapee, but I think I’ve realized I don’t really need GIMP at all. I suspect that everything I need can be found here.

I’m still learning the basics of IR image editing, but the two things I think I need to do, are to eliminate the red cast over my IR photos, and at some point switch the red and blue channels (which many people do in Photoshop, which I don’t have).

Anyway, my first question - am I in the right place? Can IR image processing be done with RawTherapee? …and my second question, is there a sub-forum that I should go to in order to read up on whatever has already been posted, and ask questions?


(Sebastien Guyader) #2

I found this, mentioning the use of the channel mixer in RT for IR processing: https://www.talkphotography.co.uk/threads/infrared-processing.655875/

And maybe this too: http://scribble-jpc.blogspot.com/2013/06/infrared-rts-simple-workflow.html?m=1


(Mike Myers) #3

Thank you for the fast response! :slight_smile:

I just found this while searching:

My Raw Therapee download should be compete soon, and I’ll try these ideas out. First, I’ll read up on the links that you just posted. Again, thank you!


(Mica) #4

Yes, this is the place for official RawTherapee support.

Seems you have a DNG, so I’d assume you can.

I’ve moved this topic into Software > RawTherapee, which is the correct subforum for RawTherapee questions.

Also, welcome. There are many helpful people here. One thing that might be of great interested is to post an infrared image as a Play Raw image. You can see topics with titles that contain [Play Raw]. The poster uploads an image to the forum licensed (usually) under the Creative Commons license. Then willing member of the forum process the raw file using the FOSS tool of choice and share the results and how the results were obtained. The original poster can see the processed image and download the sidecar file to see how the image was processed. We’ve never had an IR image, I’m sure it’d be very welcome!


(Mike Myers) #5

Thanks, for everything. Yes, I’ve noticed the [play raw] but had no idea what it meant. I will do so.

That brings up a question I hadn’t yet figured out. I did find a way to export a ‘jpg’ image of the file I was working on, but I couldn’t find a way to export my “semi-finished file” as a DNG . By then it was past midnight, and I couldn’t keep my eyes open any longer. I will keep trying until I find a way. Or, as I now suspect, do I upload the original DNG image, along with a “sidecar file”. Is there a post here on how to find and save the “sidecar file”, which I then would upload?

For whatever it’s worth, my impressions of Raw Therapee so far are that it is far more powerful than Lightroom, but I have a lot more to learn. I found a YouTube video about this - actually two - and will work with that to get the feel of how this software is used. It must be one of the best kept secrets on the internet, as of all the people working on IR images, not one of them mentioned Raw Therapee, instead showing much more complicated ways of working on an IR image. Me? I took what they did, and figured out how to do the same thing in Raw Therapee.

Hmm, is the “pp3” file the “sidecar file”? Just noticed Raw Therapee saved one next to my original image.


(Mica) #6

Yes, .pp3 is the sidecar file.

As for saving a semi-finished dng, you should just save a high bit depth tiff. But please upload the original dng here. Feel free to specify which parts of the image is giving you trouble.


(Morgan Hardwood) #7

http://rawpedia.rawtherapee.com/Getting_Started


(Mike Myers) #8

Using this getting started write-up would have been a lot easier for me than trying to sort things out on my own, but at the time, I didn’t know enough to even look for a getting started article - I just used Google. That got me to a rather old YouTube video, and while searching more, I found this newer YouTube video which is what got me to where I was as of last night - along with feedback from people in this forum:

I did find a place here in the forum to post my image and the sidecar file - I still need to learn how the forum system is organized, maybe I will do that later today.

My biggest question as of today is what to do with organizing my images. I originally thought I could do my editing in RawTherapee, then save a modified DNG image with the changes I made, and import that into Lightroom, to be stored in my many-years-old filing system. Now I know things don’t work that way.

My Leica M8.2 creates terrible jpg images, but excellent DNG files. So the camera is set to only save as DNG. Lightroom is fine for gathering up all my images from a day’s shooting, and filing them away. Lightroom is unable to edit my infrared images though (unless I also use Photoshop, which I don’t have).

Right now, none of that matters. I just want to learn how to use RawTherapee, and I’ll find a way to organize the edited files, always keeping the DNG image in the same place as the sidecar file. One possible method of doing all this, is to allow Lightroom to gather up all my images being imported from an SD card, and store them as I used to do. Then, I can use RawTherapee, and open up the image where Lightroom has stored it. RawTherapee will presumably store the sidecar file in the same place. If I do as I think has been suggested, also store a ‘tiff’ or ‘jpg’ output file, it will also go into the same place. That way I can “find” my images using Lightroom, and also work on them from RawTherapee when needed.

My main goal right now is just learning how to. use RawTherapee. One way or another, the filing system I use will sort itself out. As an editing tool, I can see that RawTherapee is far better than Lightroom.


(Sebastien Guyader) #9

@mikemyers I found this website, describing the different kinds of IR filters, their effects and use cases, I thought it could be of interest to you:


[PlayRaw] Infrared Fake Colors
(Mica) #10

DigiKam is a very capable image organizer, https://digikam.org


(Mike Myers) #11

Thanks! That page is a gold mine of useful information, and it just saved me some money.

The B+W 093 filter is like the 850nm filter on that chart, which seems to be good for black and white IR images, but doesn’t do what I want for color.

My ancient Leica filter seems to generate results similar to the 590nm filter on that chart, which produces images like what I think I’m after. I can see through that filter, so it’s obviously allowing visible light to come through.

I also found this gem of information:

" The Extra Color filter (665nm) The Extra color filter (720nm) has an effect between the 720nm and 590nm, producing more vibrant colors than the 720nm for pale yellow leaves and brighter blue skies. When to use this filter: My most used filter, this filter is best suited for processing to a traditional blue sky and white leaves, by desaturating the yellow in the leaves.

I need to go back to my image, and try out desaturating the yellow. Maybe that will give me white leaves, although I sort of like the yellow color.


(Sebastien Guyader) #12

I tried desaturating the yellow/orange leaves but since they are not bright, they just turn grey.
I think you need some 665nm filter, indeed. 720nm is nice but removes too much color.
If you don’t want waste money, I found on aliexpress a 680nm filter (brand is “Zomei”) which is close enough to 665nm, and is really cheap for testing, and eventually get a higher quality one later if you like result.
Now you made me want to buy a filter and try, as it seems my camera has a weak IR cut filter, so it could be fun!


(Mike Myers) #13

It is lots of fun, and can be very addictive. It used to be very difficult and time consuming, not to mention one of the options was to buy photoshop, but with the software here it is quite simple.

I had an hour phone call with Leica tech support to figure out what size filters my lenses take. Turns out my ancient 50mm lens takes 39mm, and the newer 35mm just takes a “Series 7” filter, no threads. There’s a special lens hood that holds the series 7 filters in place. My 35mm lens “should” use a bigger filter, but with mounting it on a M8.2 with the smaller sensor, there’s no need.

Do you have a web link to that Zomei filter?

Which camera do you have?


(Mike Myers) #14

My first reaction was why would I want yet another file organizer.

It does look like a very capable program though - but I never heard of it until now. Can it use any “top level folder”? Can I use the same folder structure I now use for Lightroom? Would either program interfere with the other?


(Mica) #15

Yes, it can use any top level folder.

It’ll use the file system folder structure for starters. Then you can tag & organize. Once nice thing is you can go to a full blown MySQL backend, if you have a really large catalog. If Lightroom is writing XMP files, digiKam should pick up on stuff like ratings and keywords. I don’t know if they interfere with one another, I’ve never used lightroom.


(Sebastien Guyader) #16

My camera is the Fujifilm X-T2. The Zomei IR filters I found are on aliexpress (here for example).
I just ordered the 680nm version. I found a review on the web, it looks like it’s not bad at all, doesn’t degrade the image quality, but maybe the slope of the transmittance curve is not as steep as more expensive filters such as Hoya.


(Sebastien Guyader) #17

Hijacking this thread a bit… I just received one og those Zomei filters (the 680nm one). The results I get are not so great, I can’t seem to get a decent “IR look” out of it in RT, but for just $20, I didn’t expect too much.

Here’s a raw file I made quickly:
DSCF5072.RAF (22.0 MB)

And 2 different outputs:



(Morgan Hardwood) #18

Not sure what you’re after, but you can probably get there using the Channel Mixer:

DSCF5072.jpg.out.pp3 (10.5 KB)


(Mike Myers) #19

I never heard of Zomei IR filters. The price sure seems good. I found a page that helped me understand what results are achievable with different levels of filtering.

 https://kolarivision.com/articles/choosing-a-filter/ 

If you scroll down far enough, you’ll see a spreadsheet of what results can come from what filters. The second row might be something you can achieve. Maybe you can boost the intensity of the colors in RT?

I’m away on a trip. I brought along another laptop specifically to work on RT. I bought a Fuji X100F, which seems to be as good or better than my Leica m8 in letting IR light to get to the sensor, and I brought my collection of red and infrared filters, to do some testing. I had to buy adapters from B&H to get to where all of them can be mounted on my Fuji. I plan to go to some spot with lots of blue sky, and lots of trees and plants, and see what I can do.

RT is still very new to me - need to relearn it, and start using it enough to get familiar with it.

The photos you posted look “flat” to me. Not enough color. Once I’m caught up to where I used to be, I’ll see what I can do with your photo.


(Mike Myers) #20

I thought I had some idea of how to process an IR image. I took this image with the same Leica deep red 39mm IR filter I used before. I found some people who suggested what the IR rating might be, but nobody was sure.

This is a test photo I took a few days ago. After doing the white balance, then the channel swap, I couldn’t find any way to make the sky blue without totally messing up the rest of the image. I eventually gave up, and made a setting for red bushes and a red sky, but that’s not what I was after.

Any suggestions?

DSCF0497.JPG.pp3 (10.5 KB)