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Color Archaeology

 The Prokudin-Gorskii Photographic Record Recreated contains a remarkable set of images from 1909-1912, and 1915 Czarist Russia.  They are black and white images containing full color information.

The images are organized in groups of three similar black and white photographs, made simultaneously (or nearly so) through red, green, and blue filters.  The original plan for these images was that they be projected through a similar set of filters, and recombined into a color images.

Through a miracle of modern technology, the computer display on which you are reading this web page is made up of many tiny red, green, and blue dots, ideally suited to displaying these images.  With an image manipulation program, such as Photoshop, you can recombine these images to get the original color back.  In doing this, you may play the role of

The general procedure of how to digitally combine the images is documented on the exhibition web site itself.  However, they make it sound like something only a photographic Tom Swift could do.  In fact, it's pretty simple if you have the right software.

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Here's how you do it with PhotoShop, or a similar photo editing program:

First, go to the web site, and chase down any images consisting of  group of three images looking something like this.  This is your starting point.


Warning, Will Robinson: Do look and make sure
there is not already a color version of your image on display!

(see original, full size image)

Note: the top image is always blue, and the bottom image is red.  This is easy to see in this image, because the blue sky will be lightest in blue, and darkest in red.

 

 

Now, use PhotoShop's rectangular select tool to select the top (blue) image, plus an extra pixel or two margin.

Create a new RGB document, and paste your image into it.

You may do this using menu commands, but a quick way to do this is to type ctrl-N, select RGB, and then type ctrl-V.

This will give you a gray image containing the information for the blue "channel" only.  We will call this image your final color image.

 

 

Now go back to your original group of three images, click on the rectangular selection tool, and drag the selection area down to include the middle image.  

Copy the middle image

Note: it is important to drag your original selection, so that the rectangular area defined by the marching ants stays the same size.

 

Note: Copy the middle image, if you haven't already!

Click on your final color image, and type ctrl-2 to activate only the green channel, and ctrl-V to paste the image you just copied into the green channel.

Don't worry if things look a little sloppy right now, we'll fix the alignment later.

 

 

Repeat what we just did, only with the bottom image.  Type ctrl-1 before pasting to modify  the red channel.

If you see the sky changing to orange, you are pasting into the wrong channel.

 

OK, now it's time to align the images more accurately.

Start by using the magnifying glass to zoom in on part of the picture, as on the right.  Pick a section with well-defined edges, such as part of the hayrack.

 

 

Use the Window>Show Channels menu item to make the channels palette visible, and click on the channel that stands out as the one most out of alignment, red in this case.

Note: make sure that the channel you want to move is highlighted, and that all four eyeballs are lit up.  Click on the RGB eyeball again if necessary.

 

Now click on the move tool, and use the arrow keys to move the red channel until it is in pretty close alignment with the rest of the image.

Note that we still have what appears to be a yellow image out of alignment - this is the blue channel in disguise.

 

 

 

So, click on the blue channel, and use the arrow keys to move it around.  This produces the image on the right.

 

 

Now stand back and admire what is very close to the final result.  

 

 

As a finishing touch, we will want to use the crop tool to trim off the ugly borders.  Most people would quit here.  But, you know, there is still something a little off with this image: it's too blue.


If you were Prokudin and/or Gorskii, and the Czar started snuffling that the color was a little wrong, you would have tweaked the brightness of one or two of the projectors.  Well, we don't want our modern-day equivalent of  the Czar to be unhappy, and luckily Photoshop allows you to adjust your magic lantern projectors by using the Image>Mode>Color Balance.

So play with the sliders to your heart's content, until you have something that looks a little better.

Color balance actually lets you adjust the "magic lanterns" separately for the shadows, midtones, and highlights,

 

 

 

OK, this looks a little better.  Turns out , we can do even better than this, using the full gamut of curves and other color controls offered by PhotoShop, but that is for another tutorial.

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