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Photography Question 
Eugene P. Watts

How to convert Black & White Pictures to Color

I have some older black & white pictures that I would like to convert to color. I have a digital cameras and stitching software. I guess I can be use red, blue and yellow filters, take a picture with each filter and overlay the three images to form colors using the stitching software. I would need a source for purchasing the red, blue and yellow 49mm filters for my camera. Do you know of a good source??? Or I can scan them and trying to convert them. I have an HP scanner model 5470Cse. Do you know of any software that will do this??? Please give me any advice, method, etc that you think will help me.

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4/12/2002 12:54:23 PM

John A. Lind
BetterPhoto Member Since: 9/27/2001
There's no simple method for doing this. If you know what the various colors of objects are supposed to be, you can "colorize" them. Typically this is a time consuming task and many colorized B/W photographs only have a couple prominent objects colored . . . ones to which the creator wants the viewer's attention drawn immediately upong viewing the photograph.

You cannot use filters to do a "reverse" color separation. Color is rendered a shade of gray in a photograph. The exact shade of gray it renders depends on several factors in addition to its color, such as how light or dark it is. Many combinations of blue and red shades will render exactly the same shade of gray in B/W. For the same reason, I don't know of any software that can determine what color something is from its shade of gray. This requires some form of human intervention to isolate each object (using contrast edges that define them) and then "colorizing" each object, one at a time.

What you're describing is "color separation" which uses specific red, green and blue filters (or their "negatives" with minus red, minus green and minus blue) to break a color photograph down into the three primary colors (or their complements). This is the method used for tri-color printing.

It's also sometimes done using B/W film and making three photographs, one with each filter. The three images are then "colorized" and very carefully recombined as a composite to create a color image. Although there may be other applications, the one I'm aware of is astrophotography for which very slow speed, extremely fine grain B/W films have the highest possible detail and sharpness.

However, starting with a single B/W image, neither of these can be run in reverse to get color.

-- John

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4/14/2002 1:38:28 AM

doug Nelson   You can do this in Photoshop, full version, LE, and probably in the new Elements version as well. Select the portion of the photo you want to add a certain color to. (Selection is a whole ball game in Photoshop; there are many ways to select something).
Choose a color from the color palette and go to Edit/Fill, and choose an opacity level. Do and undo until you get what you want.
In the future, if you want these effects, it's easier to shoot in color and mask out the areas where you want the color, then desaturate the whole image.

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4/15/2002 7:30:51 AM

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