When you are learning Photoshop as a newbie, you may face some issues that make you crazy. Especially when you open an image but find it is “Index” ra
When you are learning Photoshop as a newbie, you may face some issues that make you crazy. Especially when you open an image but find it is “Index” rather than “Layer” or “Background” in the layers palette. You can do nothing even unlock this index layer by clicking the lock icon.
You may feel confused and ask yourself if there is something wrong. A shock, isn’t it? Read the post you will know why the image is “Index” and how to unlock the indexed layer.
Indexed color mode
Your layer is “Index” because this image is in Indexed Color Mode. This mode creates an image by using CLUT (color lookup table), which stores and indexes up to 256 colors in the image. If you choose Indexed Color Mode, Photoshop will shade your image in an 8-bit color file, less image quality but higher compression rate.
How to unlock the “index” layer
There are limitations to the layers in Indexed Color Mode. You cannot unlock the “index” layer in Photoshop and the blending options are also invalid. For the extensive editing, you should convert the images to RGB mode first. Here, we provide two ways to help you complete the conversion process conveniently.
First. Use Photoshop image mode selector.
Select “Image -> Mode -> RGB color”. The “Index” layer will be converted to “Background” layer immediately.
Second. Use Paint to save the image as a new one.
Open the image in Paint, go to “File -> Save As -> PNG image”. The new PNG file is in RGB mode and could be used and edited directly.