Reducing number of colors
Printed From: Pixel Joint
Category: The Lounge
Forum Name: Resources and Support
Forum Discription: Help your fellow pixel artists out with links to good tutorials, other forums, software, fonts, etc. Bugs and support issues should go here as well.
URL: https://pixeljoint.com/forum/forum_posts.asp?TID=21017
Printed Date: 14 September 2025 at 1:47am
Topic: Reducing number of colors
Posted By: Splurge
Subject: Reducing number of colors
Date Posted: 22 January 2015 at 12:58pm
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Hey, I've been using Photoshop Elements for a number of years, dabbling. Been wanting to do some pixel art for years, and so I've recently started on the path towards learning Pro Motion. I knew a thing or two about Deluxe Paint II back in the 90's, but exact memory of those processes have since faded, though I hear Gfx2 is a good torch bearer of that modus operandi. My problem is this: I've ended up with a number of duplicate colors in my image, intended for the Weekly Challenge's color limited submissions. This is largely due to Photoshop unwittingly adding "border colors" along some of my copy-paste edges. The art itself reads as very few colors (12), but when converting the image to index mode, its number reads as" 37" in Photoshop's dialogue box. How do I manage my pixel's palette better, and zap out unwanted color dupes? |
Replies:
Posted By: yrizoud
Date Posted: 22 January 2015 at 3:25pm
Grafx2 coder here. (I played your Doom map as a teen  )A program that handles a real indexed mode internally can let you avoid the problem before it appears... Quite a few exist, free and non-free, unfortunately Photoshop is not one of them. Now, to fix up an image after the fact: Load your image Grafx2. If it's 24bit, the program will convert it to indexed mode. Open the Palette (P key) The number on the "Reduce" button tells you how many distinct colors are used.  To examine the image: If you're curious of where the problem pixels happened, hit the "Used" button, it toggles a little white marker on the right side of the colors that your image is actually using. I recommend "Reduce to - unique" to minimize the palette, then click the "Histo" button to get an idea of which colors are almost unused. Selecting a range of colors before clicking Histo can help you examine a group of colors. Clicking a color on the Histo(gram) screen selects it, so you can play with the RGB levels if you want to see which parts of your image are using it.  Reducing colors: For general color optimization, I'd recommend to eliminate unused colors (Reduce to - uniques), then sort the palette (try either Sort option). Locate two contiguous colors which are suspiciously similar. Select the two of them (click and drag), click Merge, then click "Reduce to uniques". The color count will be reduced by one, as those two colors get completely merged into one, with a RGB value set to a weighted average according to how many pixels were of this color. Repeat until you don't find any more "duplicates"  |
Posted By: eishiya
Date Posted: 22 January 2015 at 5:21pm
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To avoid getting weird colours in the first place: Make sure your selections have 0 Feathering, and that Anti-Aliased is OFF on all your tools, including selections. If you ever use any Transform tools, you can set the Image Interpolation for that to Nearest Neighbor in Edit > Preferences > General. When you want to replace a colour, use the Paint Bucket Tool with "Contiguous" turned OFF, Tolerance 0. That will replace all the colours in the image (or on the current layer, depending on the other settings) with the new colour, not just the current cluster. This way, you can avoid partially replacing a colour. |