🎨 Color and Lens Correction (RawTherapee)
When Adobe doesn't work, we have to turn to other software. For the color and lens correction, we can use the freeware RawTherapee, which is not only free, but available for PC, Mac, and Linux!
When opened up, we can go directly to our folder with the RAW files with the left-hand pane. A double-click on the folder should show the RAW files in the central pane. To batch process them all, we first need to make sure, that they are all selected. So we click on one of the images in the central pane to make sure it is active and then press CTRL+A to select them all. All the images should have now a light gray background in contrast to a dark gray background. Between the central pane and the right pane, you'll find some small buttons/ribbons. Click on the ribbon called Batch Edit.
Exposure
So the first thing we want to check is the general exposure. When photographing in a dark room or in bright daylight, it might happen that the photos are too dark or bright. We can compensate for that at least a little, although when an image is too dark or too bright, nothing can be done anymore. In the right pane, you'll find on top some symbols. When selecting the first one ("Exposure") you should see the options avaiable to you below that. The first entry Exposure is expandable by the little arrow besides it. Find the Exposure compensation slider and move it very carefully. You'll see that your photos will get brighter or darker. The important part here is, that you want to find a setting where all the photos aren't too dark or too bright. So scroll down your selection in the central pane to check.
White Balance
Ok finding the White Balance is easy, but applying it to all the photos is a bit more complicated. At least I didn't find any other solution yet. So from your central pane, select one photo, where you can see the 18% Gray value on the color checker well. Double-click the image so you will enter the Editor mode. In the right pane you still see the icons on top. Find the one named "Color" (the third one) and click it. On top of the list, you'll find 00White Balance. If you click that it will open the dialog, where you find several options of adjusting the White Balance. Click on the Pick== button and then click wihtin the image on the 18% grey patch. You should see a subtle change in colors.
We now need to apply this change to all the other photos. For that, we right-click on the already balanced photo in the preview slider on top of the central pane and select Processing profile operations and Copy. If you then hit CTRL+A again, all the other images in the top slider should get selected (indicated by a brighter gray background). Right-click now on one of the unbalanced images in the slider and select Processing profile operations and Paste. All the photos should now be white balanced. You can again click on the very left side on File Browser to go back to the Batch Edit mode.
Lens Correction
In the Batch Edit mode find the symbol named "Transform". Under it, you'll find a droop-down named "Profiled Lens Correction". So if the metadata is good, the "Automatically selected" setting is the way to go. You should also select this if you are not sure what camera model was used or what lens was attached. If you have this information however, it makes sense to select "Manually selected" and choose the appropriate options. There is a long list of manufacturers, so you should find your camera model and lens easy. The last step now is to export the images to a JPG format.
Exporting
In the Batch Edit mode, you should still have all the iamges selected. If not, hit CTRL+A again. Right-click on one of the images and select Put to queue. On the left hand side, you should see now a ribbon that is named "Queue" with the number ob images you put into that. Click on the ribbon and you are in the export menu. Select Save to folder and select a folder you want the exported images to be saved. Make sure the file format is set to JPEG and the quality is high (above 90). Deselect Save processing parameters with image as it creates unnecessary files. You can now hit the strange looking button on the left under "Queue". It takes a moment, but you should find the edited and exported JPG files in your specified folder!