Commentary # 21: July 2008
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Letting Time Paint Colors:
Photoshop and the Multi-temporal Technique

July 2008

- by Craig Wassel

This is my 21st commentary I've written for this site. I never could have imagined after writing my first one in November 2007 that I would have a couple thousand words of thought every four weeks. Each month when I wonder if I have run out of things to think and write about, the Muse of Photography ends up providing something more. I was particularly doubtful this month, as I worked on a different topic. It just wasn't coming together, so I put it aside and resigned myself to just skipping this month.

Then a most unexpected and curious thing happened. I ended up writing what follows, which is more of a tutorial born out of excitement than a commentary. I previously said that I would not write tutorials because there are already so many online photographers posting great ones. I've learned from them, so why dilute their work by writing lesser "how to" articles about the same things.

So why write one now? It began after stopping by Bjorn Rorslett's (link) website. I've visited before, but despite my strong interest in new techniques in fine art photography I had not noticed his brilliant work. This time, though, I clicked on his "Far Side" link, and saw - among other things - his "multi-temporal" photography. I searched his site for information on how it's done, but could not find specifics. I considered asking him via e-Mail, but I don't like going that route without at least putting in a little effort on my own first.

Next, I Googled "multi-temporal photography". I have learned so much what I know about Photoshop from others who have been generous enough to share their knowledge on the web. It's how I learned to do my own HDR and DRI photographs, and get results I like better than what PhotoMatix produces. Web searches usually provide so much information that it takes persistence just to determine what is the best information. This time, however, I found very, very little. Luckily, one site gave me just enough of a hint that I was able to use my Photoshop experience and understanding of color principles to figure it out.

In my searches, I noticed there were others who were looking for the same information and not finding it. In the spirit of sharing, I decided to pass along what I have learned. Before I proceed, I want to make it clear that I am not an expert on the multi-temporal technique yet. I did not discover or invent it. I don't have a gallery of multi-temporal images to "wow" anyone. I am just starting this leg of my photographic journey myself. Perhaps I will have more to say in the near future about the "vision" and art of multi-temporal. In other words, consider this a primer. If you know more than I do about this topic, please e-Mail me with anything that you feel is in error or missing. I have also saved this tutorial as a .pdf file that is accompanied by screenshots, and you can download it here for free here (link). So, without futher delay . . . .

Step 1 - The Photographs:

To me, multi-temporal images are intended to be abstract and ethereal. Bjorn Rorslett himself described it as "letting time paint colors".

To do so, our goal in this step is to take four photographs of a scene that has both static and dynamic elements. For example, you could find a rock outcropping juxtaposed with moving water or clouds. You can do it with just one exposure that is short, but I am quickly learning that letting time change the position of moving elements makes the effect more compelling and interesting. If you do decide to use multiple exposures, a tripod is needed. In this tutorial, I pour water into a champagne glass, while making four consecutive exposures of 6 seconds. It’s not an award winning shot, but the scenario demonstrates the technique.

Step 2 - Prepping Your Images in Photoshop:

Our goal here is to open our four photographs to prepare for combining them into one photograph. Before we proceed, let me re-state that the .pdf version of this tutorial is available for free here (link), and it is loaded with screenshots showing every step. If you are very comfortable in Photoshop, the web version is text only. Onward . . . .

Take one of the images (which one is un-important) and convert it to a color image that has no color. There are many ways to do this, but if you don't have a favorite method you can select: "Image --> Adjustments --> Desaturate". My favorite way is to use the Channel Mixer with the "monochrome" option selected. However you do it, it is necessary keep your image mode in RGB Color. In the next step we will paste into color channels in the Channel palette, so if you use "Image --> Mode --> Grayscale" the multi-temporal technique will not work. The multi-temporal technique CAN be done without removing color from your first image, but I am including the step here to make the results more obvious and more pleasing. Although I have removed color, the image is still in RGB mode. In other words, it is still “color capable”.

Step 3 - Pasting into the Red Channel:

Our goal is to take one of the other color images, and paste it into the red channel of our "colorless RGB" image. If you have not used the Channels palette before, download the tutorial (link) so you can look closely at the screenshots and make sure your palette looks exactly the same as you proceed.

Start by switching to any of the other three color images you have opened in Photoshop. It does not matter which one. Click "Select --> All". You should now see the dotted lines around your entire image. Now click "Edit --> Copy". Switch back to your "colorless RGB" image, then select "Window --> Channels".

Before pasting, make sure that only the red channel is active, which is indicated by the "eye" appearing next to it and not next to the RGB, green, or blue channels. You can do this with mouse clicks, but I find it much easier and faster to do with the keyboard. On Windows, hold the "Ctrl" key and then click the "1" key. On Mac, hold the "Apple" key and then click the "1" key. Also notice that Photoshop shows you these keyboard shortcuts on each channel, so you don't even need to memorize them.

Now that you have only the red channel selected, choose "Edit --> Paste" from Photoshop's main menu. You should notice the thumbnails of your image in the Channels palette changed slightly in brightness. To see the color effect of the paste you just performed, hold the "Ctrl" key and then click the "~" (Windows), or hold the "Apple" key and then click the "~" key. This re-activates all color channels of the image, and you should now see the beginning of the abstract effect.

Steps 4 and 5 - Pasting into the Green and Blue Channels:

If you got the “feel” and concept in step 3 and pasted into the red channel successfully, it now gets much easier.

Simply repeat the process from step 3. Copy your 3rd color image into the green channel of your "colorless RGB" image, and then copy your 4th color image into the blue channel of your "colorless RGB" image. Each time you paste, make sure you only have your target channel active as described above. After you complete all of your "channel pasting", you can re-activate all of the channels with “Ctrl” + “~” or “Apple” + “~” to see the results.

My final blend of the red, green, and blue channels into my first "Colorless RGB" image can be seen in the second photograph in the right column of this page. You can actually see the order that I pasted into the channels, since the water changes from red to green/yellow to blue as I poured water into the glass. I un-intentionally spilled water on the table as I poured, and that can be seen as well in the lower right of the image

Step 5 - Editing the Results:

This step is optional. After you finish pasting into the color channels and have your composite image, there may be parts of the image that you want to remove the color and return to a monochrome state. I won't go into the detail I did above, but the general idea for those who want the basics is below.

Save your composite image, giving it a new name. Re-open your first image, convert it to black and white again. Take your composite multi-temporal image, and copy and paste it as a new layer that is above your black and white image. Create a layer mask on your colored layer, then use a soft-tipped paint brush to make the parts of the lower, black and white layer visible again. You do this by choosing the paintbrush tool, selecting black as its color, then "painting" the mask with it. Painting with black erases from you top layer and reveals your bottom layer. Conversely, painting on the mask with white conceals the lower layer. If you have not worked with masks before, Google the topic and you will find many great tutorials. The mask tool is one of the most powerful tools in Photoshop, and its uses go far beyond editing multi-temporal images.

Final Notes:

The most important steps in this tutorial are:

- Isolating color channels before pasting into them. This is what isolates the colors.

- Letting time change the position of some element of your image

The length of your exposures, how many you make and combine, and whether you remove color from your base image is yours explore. You can also experiment separating out cyan, magenta, yellow, and black using CMYK mode.

Have fun, and thanks for reading.

"It's weird that photographers spend years or even a whole lifetime, trying to capture moments that added together, don't even amount to a couple of hours . . . 100,000 shots x (1/125 of a second)= 800 seconds = 13.3 minutes? . . . "

~ James Lalropui Keivom ~

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A Multi-Temporal Image

~ download the pdf tutorial

. . . monochrome

" . . . In my searches, I noticed there were others who were looking for the same information and not finding it. In the spirit of sharing, I decided to pass along what I have learned. . . . "

. . . multi-temporal

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