This is a slightly advanced article targeted at artists and photographers that take our in-person 1-on-1 course on how to photograph artworks, or those already working in the field. As such, it will gloss over many things that are not directly related to setting up RawTherapee for artwork reproduction.
Comment below with any questions or suggestions for improving these instructions.
Currently this article only covers Microsoft Windows - setting up on Mac OS or Linux is similar, though some file locations and external editor apps may be different.
Step 1: Install ICC Profiles
ProPhoto RGB
Check that you have the ProPhoto RGB ICC profile installed on your system. On Windows it will be under C:\Windows\System32\spool\drivers\color
If its not there, download it from our server and copy the file into that location: https://ucarecdn.com/76f5b720-64dc-4fd5-9fb3-7974a255609f/ProPhotoRGB.icc
Printer Profiles
If you frequently print with the same paper, make sure the ICC profile for that printer+paper combination is also in the C:\Windows\System32\spool\drivers\color folder. If you work with a print shop, such as BSLprints, ask for a copy of the softproofing ICC profiles for the papers you use.
If you don't typically print, or can't get the files from your print shop, its not a big deal it just means you wont be able to use the Soft Proofing feature to see how things would look in print.
Calibrate Your Monitor
If you have a device like a colorimeter like a Spyder X, ColorMunki, i1 Display, etc. calibrate and profile your monitor and make a note of of the ICC profile that results from this process.
Step 2: Install Programs
Install Photoshop (you don't need any of the other Adobe apps) or other image editor such as GIMP. As much as I hate to say it - for this line of work Photoshop really does make a lot of things easier and faster compared to GIMP, though its possible to do everything using GIMP if you prefer to only use Open Source or you are working on Linux.
Install RawTherapee - note that if you want to build the latest development version from source on Windows 11, you can do it either in MSYS or in WSL2, though it will run slightly slower in WSL2
Step 3: Preferences
Start RawTherapee and open the preferences window using this icon on the lower left of the window
General Tab
Link Photoshop
Linking Photoshop allows us a way to easily move files from RawTherapee to Photoshop for finishing. Use GIMP or another program if that is your preference.
Navigate to directory where Photoshop is installed and click the [Open] button
On my system its installed in C:\Program Files\Adobe\Adobe Photoshop 2024
Note that Rawtherapee 5.10 will include a better system for this that allows for setting up multiple external editors
Set Output Directory to Same as input image
This helps keep our temporary files for each artwork together with the artwork - this is especially useful when things don't go as planned.
Image Processing Tab
Default Processing Profile
For now, set Default Processing Profile to Neutral for both raw and non-raw photos - we will come back to this setting later
Micro-Optimization: Dark Frames
Most people will want to skip this section - feel free to leave the Darkframe and Flatfield settings as the default and skip ahead to the Color Management Tab section below.
If you frequently shoot in the same environment this will get you very slightly cleaner images (assuming you normally use a tripod and shoot at the lowest ISO setting of your camera)
If you frequently shoot in different environments, with very different humidity and temperature, etc. its ok to skip this step - it doesn't make much difference for what we are doing.
Basically - with the lenscap on, you will be taking images that look completely black - but if you crank up the exposure on it you will get something like this:
Using dark frames will capture this subtle noise pattern, which can then be subtracted from images.
Zooming in with Demosaicing turned off, we can see a little hot spot in one area, for example, where the sensor may be a little overly sensitive. We use multiple dark frames averaged together, done at a variety of common camera settings in our workflow, and updated at least every couple months to help keep our darkframes reflective of real-world use cases.
To put that into perspective, that dot is right here
In practical terms, it means that without doing darkframes, that spot on a photo of your artwork may be 0.1% brighter than it should be
Ok, now to set up Darkframes, should you choose to do so...
Create a folder somewhere on your computer called something like Darkframes and Flatfields with two sub folders, one called Darkframes and one called Flatfields.
In our workflow, we wont use these folders very often at all (once every couple months usually), so it doesn't need to be somewhere easily accessible.
For each lens you use to photograph artworks:
Have the camera and lens in your photography environment for at least an hour
Put the camera on a tripod or somewhere stable, either use a remote control or set the cameras timer to 2 seconds
put the lens on your camera with the lenscap on, set it to manual mode, set ISO to the lowest setting, aperture to F9, and shutter speed to 30 seconds and take four photos.
Do four more with settings as F9, shutter speed 8"
Do four more with settings as F9, shutter speed 1"
Do four more with settings as F9, shutter speed 1/10"
Do four more with settings as F9, shutter speed 1/50"
Do four more with settings as F18, shutter speed 30"
Do four more with settings as F18, shutter speed 8"
Do four more with settings as F18, shutter speed 1"
Four each of any other settings combinations you frequently use for photographing artworks (though the above covers all the most common cases)
Copy the raw files your Darkframes folder
Do those steps again every couple months or before an especially important shoot (just add the new files to the folder, don't delete the old ones)
Set the Dark-frames directory to your Darkframes folder
It may seem like you would set the Flat-fields directory setting to the Flatfield folder you created - but with our workflow its easier, in most cases, to set this to the top-level folder where you keep your raw image files - for us this the top level Clients folder. For artists it may be something like a folder called My Artworks or similar where you will make sub-folders for each photoshoot
It should look something like this, note the number of found shots, templates, and Flat-fields directory may look different for you than pictured here, thats ok.
Dynamic Profile Rules and File Browser Tabs
leave settings as-is
Color Management Tab
If you have calibrated your own display, choose your monitor's ICC profile from the list and turn off Black point compensation
If you frequently print on the same paper, choose that paper's ICC profile under Printer (soft-proofing) and turn off black point compensation
Done with Preferences, click [OK] and Restart Rawtherapee to be safe
Step 4: Open a Representative Artwork
Open a raw file of a typical artwork you will photographing, in this example we will be working with this image by Denise Hopkins. Its best if the artwork has some clear edges in it - either sharp, clear lines or impasto, that will help us set up sharpening later on.
Step 5: Set Up a Processing Profile
Now we will go through each setting and adjust only the things that we want to apply to every future image.
we need to set up using the panel on the top-right. We will work from right to left - skipping the META tab.
Low-level RAW Settings
Under the Dark-Frame settings
If, and only if, you set up darkframes as outlined above, check Auto-selection here, otherwise don't change anything under Dark-Frame
Transform Settings
Press the power button next to Crop to turn on this tool, and uncheck Lock ratio (we won't be doing any cropping right now, this will just save us a step in our image processing later on)
Next, set the Lens / Geometry -> Perspective -> Method setting to Camera-based
This will allow us to do perspective corrections in our images.
Now, make sure it shows your camera and lens under Lens/Geometry -> Profiled Lens Correction. If not, and if you mostly work with just one lens for photographing artworks, choose 'Manually selected' and select your camera and lens
Skip the Local Adjustments Tab and the Advanced Tab
Color Settings
Under color management, set the Output Profile to ProPhoto RGB (if it doesn't show up, go back up to step 1 above, install it and restart RawTherapee. You may have to restart RawTherapee twice before it shows up)
Make sure rendering intent is Relative Colorimetric and turn off Black Point Compensation
Detail Settings
Here is where things get subjective and will vary based on your camera, and to some extent your lens.
On the bottom-most toolbar in the application select the 1:1 zoom
Click the power button next to Sharpening to turn it on and try setting different values to their extremes to get a feel for what they each do, and how they fit together. You can always reset the values using the little arrow things on the right.
Click the power button next to Sharpening off and on to see how it looks with sharpening applied or not, to see if your settings are making a positive impact.
You can zoom in or out a little as you play with the settings, but don't spend too much time on how things look way zoomed in - focus on how they look at 100% zoom.
Its easy to over-do sharpening, and its generally possible to sharpen an image later, so the effect here should be somewhat subtle. Just create a bit more definition around edges.
For me, these settings work well - and this may be a good starting place for you to experiment:
Now zoom way in - like 300% or higher and turn Microcontrast on and off and see if that improves edge definition just a little bit more, if so leave it on. You can play around with its settings but I just leave these at the defaults myself.
Exposure Settings
Turn on the L*a*b* Adjustments tool and set both a* and b* to Parametric
Step 6: Save and Setup the Profile
In the top-right corner of the window, find the Save Current Profile button
Click it and you will get a window about saving it.
Call it anything you like - for example you could name it with the camera model and version of this preset profile, I'll call mine a7r4-art-v1.pp3
Save it into the default folder for RawTherapee profiles, it should be the folder that you are automatically in when you pressed that Save icon
Now, with that profile saved, on the bottom-left go back to Preferences
And on the Image Processing tab, change "For raw photos" to your newly saved profile
Click [OK] and restart RawTherapee then open a RAW file of an artwork that you have never opened before
You should see all of the things we did above automatically applied. You can adjust any settings on any new images you open without affecting your defaults.
Its a good idea to test your settings on a variety of images and to revisit all of this every six months or whenever you upgrade to a new version of RawTherapee.