Watermarking with Lightroom and ImageMagick

Someone gave me a friendly reminder that I should update my watermark today. The watermark I had been using appears at the bottom of an image, which is easy to crop. Given my unending faith in humanity, I suspected that everyone would retain the original copyright notification, but my faith was, once again, misplaced. As a result, the watermark you see above will now be a central feature of most of my posted images. The rest of this entry explains how to put together something like this yourself using Lightroom 2.4 (LR) and ImageMagick (IM).

The fact is that LR will watermark images for you automatically when you export them, but boy is it ugly. IM affords a plethora of possibilities (and perhaps even a plethora of piñatas if you ask nicely), all of which may be accessed from the command line by telling LR to execute a simple batch file after an export. Start by downloading and installing IM if you haven't done that already. Now locate the folder to which LR will export and create a new text file there called watermark.bat. Right-click on that file and select Edit, which should open a blank document in Notepad. Copy the following text into this file, save it, and close it:

:BEGIN

IF _%1 == _ goto END

CALL composite -compose screen Watermark.psd %1 %1

SHIFT

GOTO BEGIN

:END

This code is based on the code I found here. Watermark.psd may be replaced with any image you like and IM will use it as a watermark after we add some post-processing in LR. Let's do that now. With an image or three selected, open the export dialog in LR and scroll all the way down to the bottom where it says Post-Processing. Select Open in Other Application ... and then select the batch file you just created. Click Export and voila. If you'd like more options for combining your watermark with your exported images, refer to the IM site above or do a search as there are literally thousands of helpful tips available for this tool. In the meantime, I'll work on restoring said faith.

Liveview and the Hoya R72

I tried the Hoya R72 with the EF 24-70 f/2.8L this morning only to find out that it wasn't quite enough light for liveview, although shooting outside instead of through my office window might make the liveview bright enough to see. I had heard that the EF 50mm f/1.4 had a hot-spot problem, but I decided to try it anyway to see if I could get liveview working. In fact, liveview worked brilliantly with this lens and I found that I could zoom and focus as usual through the Hoya R72. I took this setup outside and shot the image of our wall above using an exposure of 30 seconds at f/2.8 and ISO 400. There was indeed a hot-spot in the image, but it was very mild and a large, gradual exposure adjustment brush with a value of -0.60 fixed the problem in Lightroom. For processing, I did something new based on an article I found here. I used a custom DNG profile I created based on the article to help me find a neutral white balance in Lightroom and then moved things over to Photoshop CS3 only to switch the red and blue channels. An excellent video tutorial on creating your own custom DNG profile was linked in the article and can be found here. Based on these results, I may very well use the EF 50mm f/1.4 for IR images and I'll give the EF 24-70 f/2.8L another try in more light.

A Quick and Dirty IR Workflow

I had some reading to do today and so I walked down to the park and set up the camera for a 45-minute exposure. Up until now, I've been shooting out of my office window and the composition isn't exactly a Minor White. After a few 45-second test shots at f/4.0 and ISO 3200, I set the remote for 45 minutes and the camera for ISO 50. It's convenient that seconds at ISO 3200 are about the same as minutes at ISO 50. The same is true for ISO 6400 and ISO 100, which makes a nice rule of thumb. Before pressing start on the remote, I attached the lens hood, tied my floppy sun hat over the viewfinder, and hung my backpack from the tripod. The sun would be shining on the filter for the next 45 minutes, so the lens hood wouldn't be any help, but the hat kept light from leaking in through the viewfinder and onto the sensor, which has been a very repeatable problem in the past. The backpack was used to stabilize the tripod on an already breezy day. With all of that in place, I hit start and sat down to read.

Exactly 45 minutes later, I packed everything up, leaving the camera on and the viewfinder covered for the ensuing 45-minute dark image, and headed home. I left the camera outside while it collected the dark image because the air conditioner was on and I would expect the hot-pixel signature to change with temperature. Once again, I sat down to read. Another 45 minutes later, I brought the camera in and imported the image into Lightroom 2.4. I set the color temperature to 2000 and the tint to -130, which are values that have worked well in the past for what we're about to do, and adjusted the exposure, brightness, contrast, and etc. as usual. When I had a pretty good looking image, I shipped the results over to Photoshop CS3, switched the red and blue channels using the channel mixer, and added a warming filter (85) at 45%. None of these steps are required, of course, but the false color image that results has a deep blue sky and warm highlights, which may be appropriate for some compositions.

In the end, the image was just off from tack-sharp, but the clouds cooperated beautifully, the camera stayed put, there was no viewfinder leakage, and the sun on the filter didn't do a thing. I attribute the softness to the f/4.0 aperture and so I imagine I'll move right back to a very comfortable f/11 when the Hoya R72 arrives.

A Foray into IR

I started this blog because I kept reading that an unconverted Canon EOS 5D Mark II either can't be used for IR photography or that the exposures are prohibitively long as a consequence of the very strong IR-blocking prefilter that comes with the camera. These remarks discouraged me from using the camera for IR work until I actually tried it and, to my surprise, found that the camera was both very well suited for long exposures and sensitive enough to even the deep IR to produce very high quality images. In fact, this camera has won awards for its long exposures, making it very well suited to IR photography when you actually want the exposure to be long. I do, so this is a match made in, well, a very enjoyable place.

The image above (and the accompanying 1:1 crop) was taken out of my office window using a Canon EOS 5D Mark II that has not been converted for use with IR, a Canon EF 24-70 f/2.8L, a Tiffen #87 IR filter, and an exposure of 90 minutes at f/4.0 and ISO 50. From this point forward, you can assume that all of the IR images presented were taken with this combination of camera and lens as this lens is the only good lens I have on the good list. Two of my other favorite lenses, the Canon EF 50mm f/1.4 and the Canon 70-200 f/2.8L IS produce hot spots, putting them on the bad list. I should also note that liveview cannot be used with the Tiffen #87 because the image is too dark, however I've read elsewhere that liveview can be used with the much more standard Hoya R72, which is really more of a Near IR (NIR) filter than an IR filter as it begins transmitting light at 700 nm, reaches 50% by 720 nm, and 85% at 750 nm. Hopefully I can locate a Hoya R72 at a reasonable price soon.

For the time being, I can safely recommend two different daylight exposures in association with the Tiffen #87: 2 hours at f/4.0 and ISO 50 or 1 hour at f/4.0 and ISO 100. Both of these assume you're shooting with the equipment above at 24mm and will produce sharp, high-quality images from about 10 feet to infinity. Make sure to set the infinity focus exactly at the 24mm IR mark on the lens (the red line extending to the number 24) and enable Long Exposure Noise Reduction in the Custom Functions as this seems to perform better than any hot-pixel correction scheme available in post-processing.