I would like to reduce the number of hues in my flat image from the full range to only four, but I would like to preserve the value/brightness (and if possible, saturation as well). I want four hues because I think it will look cool.
I tried using a hue-adjustment layer, but when I used it, it only shifted the range during conversion, so that one range was converted into another range with many colors. I want to shift a specified range to be converted to the same hue while preserving value/brightness (and maybe even saturation, if it can be done).
I am using Photoshop CS5
These are the four HSB/HSV hue values I want to use:
This is how I would like to convert the hues:
Note: I have modified this question since first posting it. Initially, I erroneously asked that responders reduce the image to four RGB values, while simultaneously maintaining the tints/values in the source image. This, however, is an impossible task, as RGB values contain tints/brightness AND hues; in RGB tint and hue are inextricably linked.
Thankfully @Wolff was able to understand what I meant, despite my poor phrasing, and along with @Danielillo, @Ryan, and @Emilie, he helped me to understand that what I was really asking for was to target four hues, not four RGB values. He then identified the four hues present in my RGB values (in HSB/HSV). Those HSB/HSV values are the now the ones I am asking responders to target in the image conversion (not RGB).
Also, as noted by @Wolff, in the first version of my post, I didn’t specify how to convert the full HSB spectrum (I didn’t have magenta-like ranges). The updated question also includes that previously omitted range.
For those who want to understand the root of the confusion (rightfully expressed by some users who provided alternate answers), these were the original 4 RGB values I posted:
Clarification update: Please know that my intention is only for screen, not print. I built a site, based on those four hues, and I thought it would be slick if the images all had the colors warped to match them. At the same time, within each of the four collapsed colors' ranges, I wanted to keep as much of the dynamics which are encoded by original value/brightness as possible. I hope this helps. Points will not be awarded by me, the original poster, for print answers, but any explanation for a print solution will likely be appreciated by the community. @Emilie, who placed the bounty on the question, can reward whomever she desires.
Thanks to @Emilie for placing the bounty on this! I really was bummed that no one seemed able to answer it before.