The answer I've heard the most (with a source citing the official confirmation) is that green, brown and gray bricks were omitted from the LEGO palette because the company wanted to discourage kids from building tanks, planes, and other realistic military hardware.
Early LEGO colors were inspired by the work of Mondriaan, which mainly consists of white, black, red, blue and yellow. These primary colors were considered to be most appealing to kids.
From the book “Brick by Brick”:
The new product was patented in 1958 and within a few years bright
yellow, red and blue Lego bricks, colours inspired by the paintings ...
I believe the main reason is so that the pieces are easy to identify in the instructions - as many LEGO sets don't have the Technic style "List of elements used in this step" it's always a fun game of "Spot the difference" to see what's changed:
If those pieces were all red, then the target audience (5+ on those sets for example) might find it very ...
Further to Alex's answer, from that source I found eleven colours that only lasted a year:
Fabuland Orange 1983
Very Light Orange 2000
Clikits Lavender 2005
Chrome Black 2009
Chrome Green 1999
Satin White 2020
Satin Trans-Light Blue 2020
Satin Trans-Dark Pink 2020
Glitter Trns-Orange 2020
Speckle Black-Copper 2006
Speckle DBGray-Silver 2006
Of course the ...
This Flickr image from Brick Colorstream shows all the known colors of LEGO bricks, charted along a timeline of when they were available. According to that image, there was one new color in 2015, "Conductive Black".
(Click for full size)
According to Bricklink, Very Light Orange was only used by single part for one year only - in 2000. It was used in 2 sets (Scala and Belville) and 1 "gear".
That part is this cat:
Another color is Clikits Lavender used by a number of parts (9, to be precise) for Clikits theme and these were produced in 2005.
Here's a picture by Ryan Howerter
Hand colors other than yellow are generally used to either match skin tone in licensed themes, or to represent some sort of gloves. The police officer you mentioned is probably "wearing" some sort of motorcycle or driving glove:
When minifigs were first introduced in the late 70s, the only ones to have non-yellow hands were the space minifigs:
I have a background in precision injection moulding, although not to the extremely tight tolerances of Lego. Here's why a manufacturer would try to reduce the number of colours they used, particularly in the old days.
Most resin (the raw material) nowadays comes pre-coloured, especially for a large customer like Lego. That wasn't the case fifty or sixty ...
A practical engineering concern could be a reason to limit the colours used for molding in ABS plastic.
The colourant added to the base plastic can affect the physical properties of the molded part. Depending on how tight the dimensional tolerances are for the finished part a separate mold may be required for each colour.
Perhaps the Lego group process ...
Again, Bricklink can help with the answer: When downloading the catalog, you specify "Part and Color Codes". This will give you a list of all part numbers and the color codes they have been produced in. To answer the question, some scripting has to be done to count lines with equal parts, etc.
To make it short, this is the top 10 list:
Duplo Brick 2x2 (53 ...
Unfortunately, this is common to several colors in the LEGO color pallette. According to this article on Eurobricks.com, The LEGO Group (TLG) made a change in the early 2000’s in how they make their colors: they used to have premixed color granules but abandoned those in favor of a system of white granules with colored dyes added in. This new system allows ...
Please contact LEGO customer service. They will send you new pieces, and even more importantly, they will make note about the quality issues. The following quote is from the LEGO Ambassador forum in regards to quality issues by Keith Severson, who is the senior manager for community support at LEGO. It is about recent quality problems with another LEGO ...
Absolutely it will. The yellowing is caused by exposure to UV light, which it will get more of with direct sunlight shining on it. If it has to be in the window you could look at some glass coverings that block some of the UV, or find a home for it else where under electric light.
Prices of bricks are determined by supply and demand, in your specific case, it is the supply side to blame. Check this site which shows how many sets was a particular colour of 2x4 brick contained in, and you'll see that there is no mention of the Dark Brown colour you are after. This means all such bricks for sale come from other sources than opened ...
Going for contrast to help you build?
This is probably the primary reason most of the time.
One Eurobricks user once said they asked a set designer about it, and they confirmed they do it to makes it easier to follow the instructions:
I had an opportunity some time ago to talk to a designer at TLG, and he told me that they use other colors to make it ...
Neither Bricklink nor Brickset knows about such a piece (all teddy bear pieces of this mold with downward arms come in non-transparent colours and are printed), so it must be either a knock-off (very low value), or a test mold (very high value).
In my experience, this typically means you used the other colored part by accident somewhere else in the model, for example in a place where it is used on its own, and it was difficult to determine the exact color of the piece at that time. This happens a lot with colors like dark bluish gray, light bluish gray and pearl gray. You will need to go back ...
There are many things such as dirt and chemicals that can cause elements to change color. Dirt can easily be washed off, but certain contaminants such as cigarette smoke can stain plastic.
The most common issue that causes LEGO bricks to yellow is interaction with ultraviolet light, most commonly from the sun. The simplest way to prevent this is to store ...
Quorneng's answer is spot on, even bricks that were from the same set might have been made from differing batches of a particular color and slight variances will produce differing colors. Purple is the most notorious Lego color for having a great deal of variance between bricks, and red is not surprisingly, also inconsistent at times.
To add to the mix, ...
As of this moment, officially - no. The ones available for sale are, most likely, test runs that made their way from LEGO factory since none of them have been included in any of sets. Red is known to be common color for running tests with injection moulding. Quite a few other test parts in Red (the color that hasn't been used by those particular parts in any ...
It (obviously) depends on what people want to buy.
If someone wants to build something, and doesn't totally care what colors are used, then they'll want to buy categorized by shape. It's so much easier to find a red 2x4 in a bin of 2x4s than to find a red 2x4 in a bin of red pieces.
But if someone wants to build, say, Big Bird, then they'll just want yellow, ...
The color of the 2x4 plate and 1x2 jumpers in the photo appears to be regular Dark Blue:
The greenish tint you mention is likely discoloration. Here is an example of a discolored regular blue piece (right) next to a fairly new regular blue piece (left) for comparison:
How uniform or consistent the discoloraton is depends on the cause and/or ...
There has been a slight change to the Pearl Gold/Warm Gold color recently that might explain the difference in color between those pieces. See this article on Reddit. Perhaps the right two “Flat Dark Gold” pieces are the newer recolor of Pearl Gold? I recall Jang from JangBricks talking about this as well in his videos.
Here is the picture from the Reddit ...
The best way to figure out what colors a set of parts have in common is to use BrickLink’s Stud.io digital design software. I am unable to show screenshots at the moment, but here are the steps:
Place the parts in question on your virtual building workspace (doesnt matter in which color)
Select all the parts together, either by:
using the ...
The colour of virtually all plastics, like paint, is an 'added' pigment so it is difficult to maintain exactly the same colour.
As others have pointed out some pigments are more susceptible to the effect of sunlight than others - red goes pale - white goes yellow.
There are several reasons for this:
There isn't just one formula for the ABS plastic that is used in
LEGO. There are actually quite a few. Depending on the color,
translucency, and function, the mix of materials will vary.
Translucent pieces are quite a bit harder and more rigid than other
Lego bricks. Mini-figure accessories tend to be quite a bit softer
There is an interesting discussion on this on the lejos.sourceforge.io forum.
the calibration values for the NXT sensor are set in the factory and seem to be different for each sensor (which implies that there must be a reasonable amount of variation between different sensors). On the NXT the RGB values are true raw values and the calibration adjustments ...
BrickLink's statistics in Aziraphale's answer give a good answer if you're only asking about parts that were commercially available in sets. But Lego has made a 2x2 tile in every single color, for their internal color charts. They don't leave Lego's hands very often, but we do have pictures :) Here are some of them: https://www.flickr.com/photos/rjmorton/...