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Latest Articles

Black and White images with a splash of color.

Arrow Image How to determine if the image was manipulated to be black and white. Small technique on watermarking (simple example). Suggested technique on adding color to the image.



Image editors are amazing tools! They can create wonderful art, touch-up old photos, and provide the user with amazing graphics as the end result. One of my favorite techniques is putting color back into black and white photos. This can be done by having a black and white image and selecting a certain area where I wish to add some color. Now, some images you see are not really black and white. These images have been manipulated by imaging programs such as Photoshop and Gimp. These images can still have color values stored in the image, although in very limited amounts. If someone ever wanted to test for any remaining color from a black and white image, they could use a black and white filter on top of it. Now, I know what you are thinking, “It’s already black and white. Why would I want to make it black and white again?” Well, the answer is that if the image has any remaining color you will see a minor change.

Some changes are so small it is hard to see them. You could always save it as a different image and then visually compare the two. In Photoshop, there is a feature called animation that you could use to set up two layers, and then play between the two. Photoshop can enable you to easily see the difference between the two images. Reason being, our eyes can adjust fairly quickly to minor change. People tend to focus upon major areas of an image, or are drawn to the image’s central, or most prominent focal point. Now, having this rendered as a small animated image, and having it flip really fast can enable you to see it flicker. This flicker is the change. Since human eyes can only adjust so much so fast we see it as it really is.
The main reason why I am suggesting in applying a black and white filter on the image is to see if has any remaining color, and to also determine what color not to add back in. If you were to place blue on top of blue would to see any change? No, you wouldn’t. If the image had red in it, adding red would tint the image red. If you add the same amount of green to the image you would cancel the color out and make it a neutral grey. From there, you can then start adding the color you wish to add in without making the colors darker in some areas than they really should be. The only case where this might be applicable might be to reveal certain aspects of an image. This brings me to another little point; you can use this technique in reverse to do a digital water mark. Although, there a various ways to do this, this is one of the easiest ways to do it. Let’s say you made a nice little graphic, and you wanted it to be black and white, but also you wanted to have a digital water mark hidden in the image for copyright. You could make your image then have a separate layer with some text or graphic very close to the color you have where the watermark will be. This color will have to be almost indistinguishable between the watermark and selected area. Now since there is a slight color difference it will be harder to see, but still remain there. Applying the black and white filter on this will make it even harder to see. But, if you were to keep a little of the color in the watermark you could retrieve this back by reapplying the black and white back on it and take out that color. This will make it change a little and be ready to make an animation to show the change resulting from the hidden watermark. This technique can be put into the subject of steganography, but that’s another story.

Now back to the main subject, adding color into black and white images. One technique is to use a selecting tool (Marquee Tool, in Photoshop) to select a specific area. Then you could ever choose a color to paint in that area, or my favorite, use the either the hue and saturation or the color balance tool. With the hue and saturation tool you could change the value of the gray image to a difference shade or highlight. You could also use it to tint the area and then add even more color to it. With the color balance tool, you can just add color directly to the selected area in resulting in a different shade or tone. Another technique would be to select a prop image above the grey image and change the layer mode of the layer. Doing this can add nice effects to the page and give the image a new and interesting look.
Again, there are many others way to perform these techniques, but I felt like sharing some of my own. Until next time, take care.

Comments

korgon August 19 2009 - 16:28:53
I found it interesting that's why I accepted it. Rated good.
elmiguelon August 19 2009 - 19:11:50
Thanks for the feedback. Always appreciated. Thanks for finding it interesting korg. And a side note: This article is more of a "cover article", it contains hints and methods for something else here within the site.
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