How do large clothing retailers change the colors

of a shirt on a model in the exact same image

[AgentQ]

How do large clothing retailers change the color/style of a shirt or other article of clothing while on a model - with the same exact creases, stance and everything else about the picture the same? I know how to do simple color replaces with an image editor, but if that is what it is, that is some amazing stuff they are doing. The patters, colors, textures, buttons, etc change, but creases and shadows remain the same (except for the underlying fabric color). How do they do that?

[stever]

Without being specific, it is normally done by using different images where the colour/texture has been changed.

As to how you would do that in a practical sense, the best way would be (using your favourite graphics programme)
1)clone the layer and eliminate all colour within the clothing item space on the bottom layer
2)eliminate all colour within the clothing item space apart from the creases and shadow on the top layer
3)turn all creases and shadow to shades of grey on the top layer
4)eliminate all else on this layer
5)return to layer underneath and fill with desired colour/texture/etc.
6)blend top layer (shadows) with bottom layer (clothing item) using whatever techniques you wish until you are satisfied

[Simplesoft]

Another idea to consider is realtime dynamic imaging (iseemedia and liquidpixels are two company's in the market). Using 1 source image on your web server, you can change the pattern and color of a defined region of the image in real time. Pretty cool stuff

[rocknbil]

In Photoshop:

Select -> Color Range

Use the + eyedropper until all the color is selected, click OK

Clean up the selection as necessary

Use Color -> Hue/saturation to change color.