Coloured fill in logic symbols


Other than the meaningless color, which is just grey when printed on a monochrome printer, I think your symbols look great.


The color is a user config, it doesn’t have to be yellow. Yellow boxes seem to be a feature of Altium, I commonly see Altium schematics like that. I thought Altium was pretty widely known among EE, perhaps many are not familiar with it. I don’ think there is any significance to the yellow box.

I would call it “body background” color, that is what KiCad calls it. :slight_smile:

I suppose you could have a consistent scheme where symbols with a “distinctive shape” are not colored (resistors, transistors, op-amps etc) - that would include “basic” symbols I think. and anything that is literally a box has a body background color. But I see that KiCad have op-amps and even crystals with a background color.

Anyway, the KLC is an ongoing spec so anyone interested should comment on


Altium is a little more flexible than that. Yes, it is common for a component in an Altium library to have a “body” color (pins, borders, etc can also be different colors) but once added to your schematic you have control over an items color or it can use the colors defined in your schematic.

Of course I meant from the point of view of someone unfamiliar with KiCad or the KLC.

As demonstrated in other threads it’s simply easier to roll your own.


I think that feature has been requested for KiCad.

I would still call it the body background color…or maybe “eye candy” if it’s the PHB.


I fall on the side of adding nothing that isn’t needed. For those of us paying for printer ink that is especially true. If you have something large like a couple hundred pin processor you can have a large area of ink. Not only is there the cost of the ink but the paper can wrinkle unless you use photo paper. Giving people the option is ultimately the way to go of course.


I don’t like the IC symbol body fills as the “some do some don’t” looks messy and I print in B&W anyway.
(Colour comes out oddly with brown borders, green wires, light blue labels)


Filling the body backgrounds with a light color (or lightly shading them when displayed in monochrome) COULD improve the readability. It identifies the symbol as definitely a device, and not just a place on the schematic where several lines happen to fall in a shape that suggests a device outline. But to be effective, it would have to apply to ALL symbols that have a closed contour as the primary feature of the symbol (transistors, gates, opamps, microcontrollers, etc). If only some symbols are filled it looks like they are being emphasized for some reason, and your mind tries to determine what the designer is trying to tell you.



I agree. But how would you do it for transistors?
(or diodes and small devices)


There already is an option, Preferences->Set Color Scheme… this is trivial stuff.

I guess that this thread is rather long and people forgot the purpose. The purpose is to create a new official library for KiCad, therefore it must conform to KLC, that is not up for debate. Additionally, for people who do not or never will use the official library it is rather pointless expressing preferences. If there are technical issues, I would like to know, but people who get confused by colors I can’t help.

I do apologize for inviting people into a free form discussion, that was not the intent.


Google image search for “schematic circuit”, the vast majority are BW line drawings. There are occasional exceptions. I imagine the following will make old hands spit out their coffee :slight_smile:

Again, we find tradition limited by techniques of the time becomes engrained as “best practice”, which becomes folklore. In the days when circuits were drawn on a drafting board and color photocopiers were science fiction, monochrome line drawings made sense. But now we have PCs and color printers, there is no particular reason for this restriction.


Split the topic

I don’t have a colour printer at home, having found a B&W laser met my needs better without making the cartridge makers rich.
In my office only us senior staff can print colour and the meter rate is outrageous.

Once you start using colour, you have to consider B&W copying and colour blind viewers. My first job was in a department of 6 people where I was the only one with normal colour vision, so I was the official resistor reader


As are most technical drawings, which is what most of us tend to create with KiCad.

This is from a 1963 issue of Electronics Illustrated.

Emphasized / highlighted, they’re synonyms. :slight_smile:

Edit: The point of the above image was to refute the statement " tradition limited by techniques of the time", clearly colored symbols was not a limitation at least as far back as 1963. Schematics may have been drawn on a drafting board but they were still capable of coloring them in. Doing so now gives the same retro look as schematics from over 50 years ago. But I’m the one stuck in the past. :confused:


“Technical drawings are line drawings because technical drawings are line drawings”. If you wanted to create an example of circular logic, that would be perfect.

Technical drawings are line drawings, because that is what was easy to create and reproduce. We see the world as solid shapes, schematic representation is purely for practical purposes, there is no particular virtue in it. It’s a graphical shorthand. If we have the technology to represent reality directly, normal people prefer it. Hence video recorders, Fritzing. Engineers seem to fall somewhere on the autistic spectrum, where colors, sounds and change are all unwelcome :slight_smile:

Here is a publication of Egyptian Engineers Handbook (incorporating Pyramid Designer) circa 3026 BCE,

Ok, now I’ve just totally forgotten what the point was. :slight_smile:


No one is asking you to! It gets very hard to tell who is trolling who with these discussions. I presented some actually good and well thought reasoning, your reasons are just subjective, which can’t be argued as having any technical merit.
By “trolling” it appears you mean “presenting valid technical reasons which I haven’t got an objective response to”.

Unless I missed a lecture which explained how the “1960s look” affects the electrons’ behavior. :slight_smile:

Ok, now you are just trolling… Please, stay stuck in the past, but don’t throw roadblocks for people who want to move forward.

Mods: Please lock this thread, it truly is totally pointless. Then delete it :wink:


Keep this polite everyone. There have been some sensible points made from both sides, so I am reluctant to delete it


This is the best thread ever!


The way I see it there are basically three groups, which will not care about background color:

  • hobby users, which do not care about part background color
  • power users, which do not even use KiCad library as they roll their own libraries
  • power users, which clone the library, and apply changes in their own local branch. They can change the background color and still fetch and merge any further changes to the official KiCAD library. It is really fabulous that the libraries are human readable and on GitHub.

The two other groups, which can have a problem with background color:

  • hobby users using KiCAD official. To them I say: Tough luck
  • power users using KiCAD official along their own libraries. To them I say: make an effort and move yourself to upper two groups.


I personally do not like the background fill on library parts; for many of the reasons stated above.

I’ve been using black and white schematics for quite some time, and turning them colorized with pen markers for quite some time.

My suggestion is to create a poll on the forum and see if members really care about the background color. Then, adopt whatever results into your design; if it happens to not meet the current KLC about background color, then include the poll results as a reason for non-compliance of that part of the KLC.

The KLC does provide for this variance and seems to me a way to make the majority of active participants use your work.