Photoshop: "Indexed" - what does that mean?
Layers in Photoshop can be indexed. This practical tip explains exactly what that means and how you can edit indexed layers as usual with the full functionality of Photoshop.
That means "indexed" in Photoshop
Due to the versatility of the term "indexed", an "indexed level" is by no means self-explanatory. Indexed colors are sometimes a very useful measure in Photoshop and other graphics editing programs, such as GIMP. That means a level is "indexed":
- In Photoshop and other graphics tools, you can index colors, that is, save them on a "color table" or "color palette" and retrieve them from here.
- If you use exactly four colors, but want to choose them freely, you could simply save the graphic with 24 bits.
- However, it is more efficient, i.e. space-saving, to code this image with 2 bits, for example as a 2-bit GIF or PNG.
- A color palette is also saved so that the computer knows which bit sequence should correspond to which color, so the colors are "indexed".
- Only with standard palettes, such as 1-bit black and white and grayscale with 8 bits, color tables do not have to be saved.
- In an indexed level, however, the number of permitted colors is now limited by the color table. Effects such as transparency, blurring and color filters may not work.
- Indexing can be useful so that you only work with the colors that are actually contained in your target format.
Photoshop: How to edit indexed layers
There are three ways to edit indexed layers in Photoshop, sorted by their elegance:
- Navigate to "Mode" via "Image" and click on an alternative to "Indexed colors", for example "Grayscale" or "RGB color".
- Duplicate the layer and edit the duplicated layer as desired.
- Take a screenshot at a zoom level of 100%, paste it into a new Photoshop project and cut out the image.
- It is said that sometimes it works, at least in some versions of Photoshop, that you double-click the indexed layer and close the subsequent information window by clicking on [OK].
On the next few pages, we'll help you if Photoshop doesn't start or stops working.