Colours affected when importing a layer

[WristyGymnast]

I'm trying to edit a GIF I've downloaded.  

When I try to import a layer from another image that I've edited to the gif image, the colours are affected.  

I want to duplicate and add this layer to each of the gif layers.  In short, I want to change the face of the person in the gif.

Why are the colours changed on the imported layer?  I have a feeling its something to do with the channels: the import original has the RGB and Alpha channels, the gif only has Indexed and alpha.

Any ideas?

[rich2005]

The gif format uses a colour index which is a map of a limited set of colours. Maximum 256 colours.

An RGB image can have many more colours by mixing those red-green-blue values.

The best thing to do is change the gif to rgb before adding the RGB image Image -> Mode -> RGB

Thing to remember, the format used will be that of the original image.

Open an Indexed image, import a RGB and the result is Indexed.

Open a RGB image import an Indexed and the result is RGB.

Looks like you are making an animation, so work in RGB until all the editing is complete, then export as an animated gif and you will be back to indexed.

[WristyGymnast]

(12-04-2018, 01:51 PM)rich2005 Wrote: The gif format uses a colour index which is a map of a limited set of colours. Maximum 256 colours.

An RGB image can have many more colours by mixing those red-green-blue values.

The best thing to do is change the gif to rgb before adding the RGB image Image -> Mode -> RGB

Thing to remember, the format used will be that of the original image.

Open an Indexed image, import a RGB and the result is Indexed.

Open a RGB image import an Indexed and the result is RGB.

Looks like you are making an animation, so work in RGB until all the editing is complete, then export as an animated gif and you will be back to indexed.

 nice one, I'll give this a go! 

[Ofnuts]

(12-04-2018, 01:51 PM)rich2005 Wrote: The gif format uses a colour index which is a map of a limited set of colours. Maximum 256 colours.

Looks like you are making an animation, so work in RGB until all the editing is complete, then export as an animated gif and you will be back to indexed.

But remember that you will be limited to 256 colors total across all frames. For instance, when you merge a mostly red image/animation (256 shades of red) with a mostly blue one (256 shades of blue), when you export choices are done, and you will end up (in the good case!) with an image that has 128 shades of red and 128 shades of blue. Then your red or blue gradients won't look as smooth, your edges will look a bit more pixellated, etc....

[rich2005]

No way of knowing what the OP is using as source images

but maybe we should enter the 20th 21st century and use Webp format.



Comparison: optimised gif size 113k 256 colours Webp 97k 48000 colours. Very slow to render the animation but it gets there.

I had to zip the file for the forum. Unzip it & try it in your web browser. Let us know which browsers work.

Edit: Firefox is still dragging their heels, although it is promised
I use Slimjet mainly and it works there, Vivaldi browser also works.