Possible algorithm for converting photos to NES

A place for your artistic side. Discuss techniques and tools for pixel art on the NES, GBC, or similar platforms.

Moderator: Moderators

tepples
Posts: 22705
Joined: Sun Sep 19, 2004 11:12 pm
Location: NE Indiana, USA (NTSC)
Contact:

Re: Possible algorithm for converting photos to NES

Post by tepples »

This duotone technique resembles the process I used when trying to make NES-style portraits of #nesdev regulars.

The hardest part is automatically coming up with a palette, and the LBG algorithm described above might work well.
Sik
Posts: 1589
Joined: Thu Aug 12, 2010 3:43 am

Re: Possible algorithm for converting photos to NES

Post by Sik »

dougeff wrote:Maybe I should explain how to do a duotone, since the Wikipedia page doesn't...

First you turn the image into a black and white. Then instead of shades of gray in the palette, you use shades of pink (faces) or shades of blue (other things).
This description seems off (you just described variants of monochrome), duotone is more like converting it to a two-channel color format (instead of three-channel like RGB). On the NES, that'd be like treating the tiles as two 1bpp channels instead of a single 2bpp one (and you'd need to resort to dithering too).

At which point just plain grayscale 2bpp with dithering is a better choice, just using a different hue/saturation for the shades.
User avatar
dougeff
Posts: 3078
Joined: Fri May 08, 2015 7:17 pm

Re: Possible algorithm for converting photos to NES

Post by dougeff »

Here's what I mean. Trust me I've made 100+ duotone images over the years...

1. Color photo
2. convert to black and white
3. convert to duotone
4. convert to NES 4 color palette

And you don't really need step 3, I just included it to demonstrate an actual duotone image.
Attachments
duotone1.jpg
duotone1.jpg (25.91 KiB) Viewed 3118 times
duotone2.jpg
duotone2.jpg (67.58 KiB) Viewed 3118 times
nesdoug.com -- blog/tutorial on programming for the NES
User avatar
dougeff
Posts: 3078
Joined: Fri May 08, 2015 7:17 pm

Re: Possible algorithm for converting photos to NES

Post by dougeff »

(Edit)

My point, is that the final product will LOOK like a duotone, not that you need to use these steps to get there.
nesdoug.com -- blog/tutorial on programming for the NES
User avatar
tokumaru
Posts: 12427
Joined: Sat Feb 12, 2005 9:43 pm
Location: Rio de Janeiro - Brazil

Re: Possible algorithm for converting photos to NES

Post by tokumaru »

dougeff wrote:I don't expect to see full color pictures, but anime style flat images and reduced color images could be a possibility.
Yes, and my point is that you can already make those kinds o images with decent results if you do things manually. Automating the process might make it faster, but it won't generate better results than what good artists usually produce.
Post Reply