: Make a desaturated image transparent keeping only shadows & highlights I've been trying to do this for a few days now and have not gotten the results I need. I'm not sure I'm using the correct

@Pierce403

There is easier way - select the white background, invert it, define brush preset, create new file based transparent, grayscale - and this is. Select the brush, which is the last in the list and click once with black fourground swatch. Voila!
Than you can save as web - png.

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@Turnbaugh909

For this, you best create separate channels for the shadows and highlights.

The shadows can be directly taken from the white T-Shirt, and be used as a multiplicator (0-100%) for the shirt's color (layer mode: multiply)

As for the highlights, this really depends on the material. Cloth doesn't reflect much light on the surface, so most of its color comes from diffused light (the shirt's color). To extract the specular light, I'd use a high-pass filter (histogram adaption: only the bright colors, and none of the dark colors) on the white shirt's image and use that to brighten the shirt, but only with maybe 20% (low reflection).

Layers:



Resulting images:

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@Tiffany317

When assigning white as alpha channel for transparency we will not be able to have opaque highlights, as these per definition will be white, hence fully transparent.

To have an alpha channel sparing both highlighted white areas, and black shadows we better choose a grey color for assigning alpha.


To show the effect more clearly I first made your original image darker, and increased contrast. You will need to both, adjust the source contrast, and choose a grey level which suits your needs best for better results.
Then I assigned an alpha channel to a 'grey' color (rather than white):




Now when we overlay this picture with e.g. a green background we can see, that both highlights, and shadows are maintained.



We can see, that when used on dark colors the white areas of the original image may still be too bright for the desired effect. This can be overcome when we choose a grey rather than a white source for creating our alpha channel template.

Below (top left) I used a grey bucket fill with 20% opacity on the white original. After assigning a transparancy alpha channel to grey (top right) we can overlay a colored background (left black, middle dark red, right ivory white) to achieve the bottom line effects.

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