How to unlock an “index” layer in Photoshop

When you start learning Photoshop, you may encounter some problems that are just crazy. Especially when you open an image, but find in the palette of layers that it is an “index” layer, and not just a “layer” or “background”. You can’t do anything, you can’t even open this index layer by clicking on the lock icon.

You may be confused and perplexed: “Maybe I’m doing something wrong?” Read this article and you will learn what an “index” image is and how to unlock an indexed layer.

Content
Indexed Color Mode (Indexed Colors)
How to unlock a layer (how to disable indexed colors in Photoshop?)
The first way: use the Photoshop image mode selector
Second way: use Paint to save the image again
Indexed Color Mode (Indexed Colors)
The layer is “indexed” because this image is in indexed color mode. This mode creates an image using CLUT (color lookup table). When answering the question about how many colors are used and the indexed colors mode, it should be said that CLUT stores and indexes up to 256 colors.

If you select the indexed color mode, Photoshop will change the image in an 8-bit color file, reducing its quality and applying a higher compression ratio.

How to unlock a layer (how to disable indexed colors in Photoshop?)
There are restrictions for layers in indexed color mode. You cannot unlock the “index” layer in Photoshop, and the blending modes for this layer also do not work. For advanced editing, you must first convert images (indexed colors) to RGB mode.

There are two ways to help complete the conversion process.

The first way: use the Photoshop image mode selector

Select Image – Mode – RGB Color. The index layer will be converted to Background.

Second way: use Paint to save the image again
Open the image in Paint, go to File – Save As – PNG Image. The new PNG file will have RGB mode, and it can be used and edited directly.