Not an expert, but try this. Open the image. On the right there should be a small window named 'Layers'. If not, go to the view tab and click layers. Also go to the image' tab and ensure the RBG is ticked. In the little layer window, highlight the layer that you wish to make paler and adjust the opacity (there is a tiny adjustment window for this at the top right of the layers window). If the image that you have opened is not a PSD image - such as a jpg, gif or bmp - the image may have a little lock on it in the layer window, right-click it and make a duplicate layer, you can then delete the locked layer or click on the little eye to make it invisible. When finished, click the "T" on the toolbar on the left and you can write over the image to your heart's content. When finished, save as jpg or whatever and opened the image in an ordinary viewer to ensure the it has the right opacity before closing Photoshop. Enjoy.