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Topics - Piotr
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General Discussion / This forum makes no sense
« on: August 15, 2017, 04:15:51 pm »
Criticizing a great program, a great 256 color palette, BAN?! This forum makes no sense at all.

General Discussion / Challenge candidate: Limited gamut
« on: January 16, 2017, 03:24:14 pm »
Goes to Challenges and Activities category if accepted.
Make pixel art with limited color gamut. Make use of the tool for picking color from image.
1. Custom 2-dimensional color map

Basically black-blue-red-white corner map, with tweaked ramps so light red is yellow and light blue is cyan, as well as some areas for more colors. The straight line from black to white is roughly grayscale.

General Discussion / How to make a challenge?
« on: January 15, 2017, 11:04:31 am »
I want to make a challenge where people make pixel art with restricted color gamut, such as grayscale or no red channel. How do I make a challenge? The category for challenges appears to be closed.

General Discussion / Make your own ellipses (pixel art)
« on: January 07, 2017, 05:37:12 pm »
Your task is to make ellipses from 1x1 to 12x12. You can choose whether they are antialiased or whether they are not anti-aliased. I'll start with my ellipses:

Follow the format above but use your own text. You can make multiple sets, they can be same or different, but all in one post.

You can make and share palettes here. Don't rate palettes, just create a palette and describe uses for colors. Note that 3 and 9 color palettes can be used for ternary computer storage. My palettes are text-based so you can modify source code. It's in this format:
Code: [Select]
black, blue, red, magenta, gray, lime, cyan, yellow, white, #ff7f00, etc...

My 2 color palette:

This is a basic 2-color palette, intended for basic text (think yellow on black). Could change the yellow color into cyan, green or white.

My 3 color palette:

The cyan makes a sky, the yellow is for sun. Dithering them results in green for grass. You could also dither yellow with black for dirt, or cyan with black for rain.

My 4 color palette:

This one adds red that could be used for fire and dithered with yellow. Also contains a ramp black-red-yellow that can be used for anti-aliasing.

Classic 8 color palette:

Can use any color by dithering. The palette colors are nice and saturated.

My 9 color palette:

Adds gray for anti-aliasing.

I have an image with binary storage palettes (I used my custom font):

16-color palette's utility is to complete biggest gaps (for human eyes) in hue circle, and to add some grays and brown. Colors can be inversed.
256-color palette is a websafe palette with anti-aliasing ramps to create in total 16 equal spaced shades of black-white, black-yellow, black-cyan and black-red.
4096-color palette uses 16 levels/4 bits for red, green and blue.
Grayscale and yellowscale are for anti-aliasing.

General Discussion / A closer look on interesting 256 color palette
« on: October 04, 2015, 07:20:47 am »
I've seen an interesting 256 color palette here:
I understand it! Here is the mechanism:
Red uses values 0, 42, 85, 127, 170, 212, 255.
Green uses values 0, 23, 46, 69, 92, 115, 139, 162, 185, 208, 231, 255
Blue uses values 0, 51, 102, 153, 204, 255.
Depedencies for green:
Green uses regular values if red and blue use same sets (regular or bold).
Green uses bold values if red and blue use different sets.
Depedencies for blue:
Blue uses regular values if red and green use same sets.
Blue uses bold values if red and green use different sets.
This makes 7x6x6 or 7x12x3=252 values. Black, white, red and cyan are represented exactly.
Remaining values are filled by grays: 51, 102, 153, 204.

General Discussion / Best palettes (any size)
« on: September 28, 2015, 09:34:20 am »
Start with 2 colors, then add a color repeatedly in a best way. This is not a question, just post your own results.
My first attempt:

Also (optionally) say the purpose/bias of your selection. This selection fills most gamut in smaller sizes, if dithering is used. Also, final 16 colors are similar to ZX spectrum, except that here dark colors use 170, there is CGA distinctive brown and duplicate black is replaced by orange. The reason why CMY colors are before RGB is that they seemed more useful in 2~4 color palettes.

General Discussion / What is best 256 color palette?
« on: September 01, 2015, 02:54:55 pm »
I want to know what is best 256-color palette. Not all entries have to be occupied.
I know these:
* Subset of 10-10-10 level RGB (1000 colors). First 125 colors are combinations of 5 levels of RGB each with LSB off. Next 125 are same, but with LSB on. For total of 250 colors, 6 remain.
* Subset of 16-16-16 level RGB (4096 colors). The format is IIRRGGBB: R, G and B are two most significant bits of each component, while I sets 2 LSBs of each component.
* Another IIRRGGBB format palette, but I sets color brightness to 25, 50, 75 or 100 percent of original. There is more fidelity in darker colors, but there is some redundancy: blacks, and 66% red with 50% brightness is same as 33% red with 100% brightness.
* 256-level grayscale for full brightness fidelity but no color/saturation fidelity at all. Variant: 128-level grayscale and fill remaining 128 colors to compensate for human's limited vision (human sees 21-bit RGB, not 24-bit).
* Level combination: each of 4-16-4, 8-8-4, 6-6-6, 6-7-6, 6-8-5, 7-7-5, 5-9-5, 5-10-5 and others for RGB are accepted.
* As above, but for hue, saturation, value/light. NES tried this.
* 2 bits for red/blue, 3 bits for green. Other bit is LSB of red and blue.
* Make four cubes of 64 colors, where there are 4 RGB levels in each cube chosen from 8 levels. Example: 0-2-5-7, 0-1-2-3, 2-3-4-5, 4-5-6-7. Configurator link:
* To reduce large RGB bit-based palette by 2 bits, merge LSB of red, green and blue to one bit, as long as they all exist. If there are only two normal components with their own bits, you can only merge them to compress by 1 bit. This preserves all grays of palette (only if there are equal bits of each component), but reduces hue/saturation fidelity.

Here are samples for some of them:
Uniform HSV selection: There are 15 hues, 2 saturations, 9 values in full saturation, 7 values in half saturation, 17 grays and some transparency.

Uniform RGB selection: There are 4 bits for each component, where 2 least significant bits are shared between components. As a result, there are 2 bits for each component and 2 least significant bits shared between components. There are 18 hues, 2 saturations and 16 values. Best case precision is 12 bits, while worst case precision is 6 bits.
In other words, it's 4 RGB cubes, where each RGB component can be any of following values:
  • 0, 68, 136, 204
  • 17, 85, 153, 221
  • 34, 102, 170, 238
  • 51, 119, 187, 255
Example: 255, 119, 51 (orange)

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