This is a quick and dirty tutorial on making a mask from a single colour channel in Photoshop. Below is a B&W photo that needs some restoration, it has some bad damage on it. Most of the damage is the redish discolouration. So in order to fix just this area it would be real handy if we could make a mask of just that area so we can correct it. Fortunately there is a way. Step 1. Use the channel mixer adjustment layer to highlight which channel has the damage, using the red green and blue sliders. Step 2. Switch to the channel palette and copy one of the colour channels (doesn't matter which as the image is now B&W.) Step 3. Make the copied channel a selection.  Step 4. Apply this selection as a mask to any adjustment layer on your original image.  PixelFIX - Photo restoration and photos repaired, from $15. The restoration and manipulation specialists. Click here for 'fancy view'

Colour photos can be affected badly by age or by breaking down of chemicals in the paper. Sometimes the easiest and most inexpensive solution is to turn the discoloured photo into black and white. This method if used correctly and with some careful use of the channel mixer adjustment layer in Photoshop, will remove the discoloration and give an nice evenly toned black and white image. Like the example below. This Photo is from   PixelFIX - Photo restoration and photos repaired, from $15. The restoration and manipulation specialists. Click here for 'fancy view'