Reducing the number of colors

mercphoto

This could easily fall into the realm of turning a photo into an illustration, but I'm wondering exactly how to go about this. I've had some luck with Topaz Simplify in doing stuff like this but wondering about other ways. See attached photo. At sometimes I'd even like to have even less color gradation that what that attachment shows.

I've tried polarizing filters before but often not pleased with the resulting color choices the algorithms pick.

Richard

Have you tried saving it as a GIF? If you have Photoshop, look under the Save For Web file menu option. You can select anywhere between 2 and 256 colors (in steps of powers of 2). I've never needed to this myself, but you can also customize the color palette to taste if you don't like the algorithm's choices. You can always convert it back to JPG if you need to.

Another quick PS method is using a posterize adjustment layer and playing with the number of levels. It tends to make images look like comic books IMO, which may or may not suit your purposes, dunno.

arodney

Photoshop>Image>Posterize enter lower values.

Peano

The example you attached shows more than just reduced colors; it also has a sketch/painted effect. You might try FotoSketcher. It's free. (Taking a second look at your example image, it might just be posterized in Photoshop. Pretty small image, so it's hard to judge.)

ziggy53

Apparently, an artist named "Ricardo" does some of the Racer covers. While they may be inspired by photographs, I doubt that they use much computer automation for the final rendering.

http://www.ricardo-car-artwork.com/work/

Perhaps a vector based software might be used, superimposed upon a photographic image for the purpose of subject shape. (CorelDraw used to have that capability; don't know if it still does.)

mercphoto

Thanks everyone. Nice find Ziggy! And I think you're right, he isn't using photographs for his starting points and probably why I'm having a hard time getting results like that from my photographs. For now think I'll just keep using Topaz Simplify.

ziggy53

Thinking further outside the box, possibly use RawTherapee and Contrast by Detail Levels wavelets at 5 levels to help reduce detail at higher frequencies (where the fine details exist) leaving the coarse details including basic shapes. The Median Filter can be employed to further reduce fine detail and smooth color transitions, making it easier for posterization algorithms (in other software).

GIMP and (optional/additional) Wavelet Decompose (WD) offers somewhat different processes and results. Patrick David has a great mini-tutorial of the GIMP-WD methodology and some results. http://blog.patdavid.net/2014/07/wavelet-decompose-again.html

Some time back we had a user ask about reducing facial blemishes without losing too much detail. I worked up a treatment but we had other good responses so I didn't answer in that thread, but here you can see the type of control it gives. (RawTherapee and Wavelets) (Not my image. Will remove at original user request.)

Original image:




None of the above are finals, just treatments.

mercphoto

Thanks again. And just found some info on a forum about how to do frequency separation in Affinity Photo, my current favorite Photoshop replacement. I agree that it could help the posterization algorithms if the color gradients could be smoothed out before hand. I think that is a big part of the thing I don't like about previous attempts at posterization I've had.

bham

mercphoto wrote: »

Thanks again. And just found some info on a forum about how to do frequency separation in Affinity Photo, my current favorite Photoshop replacement. I agree that it could help the posterization algorithms if the color gradients could be smoothed out before hand. I think that is a big part of the thing I don't like about previous attempts at posterization I've had.

I also found to get better results from topaz simplify it to reduce the pixel size of the image first, then filter, then if needed upsize again. Get better effects with less pixels in simplify for the effects I believe you are looking for.

mercphoto

Thanks, bham. I went through some of my previous Simplify attempts, and I think now I like them better than I did at first.

https://www.flickr.com/photos/bjurasz/albums/72157650376627900

bham

mercphoto wrote: »

Thanks, bham. I went through some of my previous Simplify attempts, and I think now I like them better than I did at first.

https://www.flickr.com/photos/bjurasz/albums/72157650376627900

Yeah it took me playing with it for a while to figure that out, but IMHO lower res lets the filter work better and makes it more distinct.

Glad I could help.

SprostyPhoto

> @Peano said:
> The example you attached shows more than just reduced colors; it also has a sketch/painted effect. You might try Fotosketcher

Thanks for the tip on FotoSketcher, Peano! Been playing around with it lately.