White Dots Appear After Rendering GIF

[ChrisR13]

I am trying to make a short GIF.  I was using After Effects to create a MOV file and then use that file in Photoshop to make my GIF, I also tried to make my GIF straight out of Photoshop and I ended up with the same result so I am hear for help.  I have 9 images that are nearly identical, a color ad changes within a matching frame for 9 different ads.  The images I have ae high res PSD files. I can convert them to anything needed.  The GIF needed is for a website and needs to be 650px wide.  I was setting the time to 1.5 seconds per ad. I used RGB+Alpha to retain transparency, Output module was Lossless, colors in Photoshop were set to 256.  After rendinging the colors have a comic book halftone type look to them.  I am not sure what setting I am missing. Should I save my orignial 9 images differently?  Thanks!

[Myra Ferguson]

It looks like the result of dithering and diffusion. A GIF uses a color table to represent the contents of the image. When there aren't enough colors to accurately represent the colors present in the image, then there are some tricks like dithering and diffusion to try to represent the variation in color without actually having those colors in the color table. You can also use dithering with noise or a pattern. Noise looks somewhat similar to diffusion, but the pattern setting looks like 1990s art. You can turn off dithering and diffusion, but the end result usually looks better with it.

My guess is that there is a lot of variation in color throughout the image that we don't see in the posted samples. I'd recommend going back to the original image or clip and changing the backgrounds (where you see the dots during export) to a color that is more predominant in the rest of the image or clip.

[ChrisR13]

Thank you,  I ended up learning a bit more about dithering on my own after posting.  I achived best results I could with a GIF and 256 colors.  I appreciate your help though!