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Use of Colour on Drawings

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JasonB15/01/2019 16:06:03
21435 forum posts
2448 photos
1 articles

As I'm working on a couple of sets of drawings that won't just be for my personal use I thought I would canvas opinion as to what people prefer in the way of colour on a drawing. I'm specifically talking about what is on the 2D print that you will be working from and even more specifically the shading of the part. I'm not thinking about the use of different colours of lines for things like dimension, ctr, hidden detail, etc which I personally don't like or the use of a multitude of colours for each part during the design stage.

Below are 3 possible options

1 Just plain lines. No different to how drawings have been presented for years and how I havepreviously done the last couple of drawing sets shared here.

allman drawing1.jpg

2. The 3D image has been coloured based on what I used during the 3D modelling which in the case of this part is a darkish grey for cast iron, steel would be a lighter grey, brass yellow etc. Uses a small amount more ink and I have kept the 3D image smaller than the scale of the actual part to reduce this.

allman drawing2.jpg

3. Fully coloured. This would definately use up quite a bit of ink which some people prefer not to do and I tend to feel the same preferring to spend my money on metal rather than ink refills. The other downside is that the darker grey can obscure some of the lines and dimensions and may be worse if printed on basic paper as the ink can bleed a bit. Plus side it it can look nice.

allman drawing 3.jpg

Look forward to your thoughts and Comments


Andrew Johnston15/01/2019 16:15:53
6264 forum posts
677 photos

1. My preference

2. Maybe, although a shaded isometric view doesn't add much - an exception would be an assembly or partial assembly where different shades would delineate the parts, and it would make sense if the shades reflected the materials

3. Definitely not, adds nowt and tends to obscure the engineering detail


Thor 🇳🇴15/01/2019 16:17:55
1411 forum posts
41 photos

My preference would be No 2, as Andrew I think No 3 obscure detail and makes it more difficult to read for my old eyes.


Martin Johnson 115/01/2019 16:20:43
131 forum posts
1 photos

I think option 2 is a reasonable compromise.

Another personal grouse is showing edges, centrelines and dimension lines as all the same weight. BS 308 (when I learnt it 45 years ago required the edges to be a heavier weight. I find 0.5 mm line thickness works well on Turbocad, with 0 thickness for the rest (including hidden edges).

Another another personal grouse is still clinging to BA fasteners regardless. M3 would be near as spit the same as those 5BA, and both fasteners and taps will be a fraction of the BA price. 3 BA could go M4 or M5 depending.

In fact, why not go metric for the whole hog?

You wanted opinions..................


fizzy15/01/2019 16:24:50
1813 forum posts
120 photos

Keep it one colour for me for best clarity - they only ever get worse with age

Russell Eberhardt15/01/2019 16:46:15
2703 forum posts
86 photos

For me 1, 2, and 3 in that order. Perhaps I am a bit of a stick in the mud having first been trained in drafting over 50 years ago.


duncan webster15/01/2019 16:47:43
3508 forum posts
63 photos

I do all my 2D CAD on black background with multi colours, but when I print it off I select monochrome, so it prints black lines on white background. this might not be an option with 3D

Jim C15/01/2019 16:48:27
73 forum posts
4 photos

Hi Jason, I would go for option 1 for presenting a drawing for manufacture. The isometric view whether rendered or not is a worthwhile addition, especially for engineering apprentices!

HOWARDT15/01/2019 16:51:36
778 forum posts
28 photos

I don’t care, the most important is to have all the information and be readable. You do have to remember to consider how the drawing may be reproduced. Not all have access to a full colour A0 printer may be just a A4 black only. Others may only want to view on screen.

SillyOldDuffer15/01/2019 17:00:45
7549 forum posts
1680 photos

I like drawings that are attractive and easy to read!

A plain 2D drawing (Option 1) is best at showing dimensions and therefore essential in the workshop but they are poor at expressing shape. Ever confused 1st and 3rd angle projection or misinterpreted the intended form? Adding a 3D representation (Option 2) adds clarity to the shape, but even 3D can be ambiguous. It's sometimes helpful to bring out the structure by shading or with a touch of colour.

Taking Option 3 to the extreme, I often find photo-realistic images helpful as well. They give a clear idea of what the finished item looks like and provide important clues as to how parts relate together, and perhaps other details such as the paint job or finish. During assembly, which is an important part of Model Engineering, I find exploded parts and sectioned views are often clearer in full colour than in black-and-white. (A Haynes Manual that only gave the car mechanic Option 1 production drawings to work from would be a failure.)

Colour becomes counter-productive when overused, misused or confused. Despite no-one wanting garish confusion in a technical drawing, there are too many examples of just that about. Perhaps it's impossible for the average draughtsman not to get drugged by Glorious Technicolor!

An advantage of a 3D CAD package is that it can produce all these drawing types without a lot of extra work. But as always, the author has to target his audience carefully. If colour adds value I'm all for using it. Otherwise, don't!



Edited By SillyOldDuffer on 15/01/2019 17:03:01

Ron Laden15/01/2019 17:10:26
2248 forum posts
446 photos

I would be happy with No 1 or No 2 and I like the idea of colours representing the type of material. Agree with Andrew that the material/parts colours could work well with part or full assemblies.

Bazyle15/01/2019 17:26:07
6038 forum posts
220 photos

Only 1. Lots of printers just can't handle shades of grey as you pointed out. Colours and shading is also a big problem with projectors though not likely to be relevant here, unless you were doing designs for a model making school class.

Steambuff15/01/2019 17:35:35
518 forum posts
7 photos

My preference is

2D - Just plain black and white lines, as it has been for years

3D - Colour but ensure that it can be printed in Mono OK

i.e. No. 2


Martin Connelly15/01/2019 17:57:05
1888 forum posts
203 photos

I have spent a lot of time producing drawings for other people to use and have always used different line weights for edges as Martin J above preferres. The circle delineating the detail view in the example above is confusing because everything has the same line weight. I also add a 3D view when it will help and shade it only if it helps.

BS308 paragraph 8.3 "Choice of views" states:

"All views should be chosen to impart the maximum information clearly. Hidden detail lines should only be used where essential but should not be used for dimensioning.

NOTE. An isometric or similar view of a complex part or assembly may be of considerable value in the understanding of the drawing. "

Seems like a sensible methodology to me.

Martin C

Grindstone Cowboy15/01/2019 18:44:15
708 forum posts
58 photos

I like Option 1

John Paton 115/01/2019 18:45:57
304 forum posts
17 photos

Good drawing practice would be to have the coloured fill or shading on a separate layer to the object outline and dimensions on yet another layer.

Hopefully in the modern age the drawings will be made available electronically in 3D for use by those clever and lucky enough to be able to make at least some of the components using CNC machinery and if so then the reader can open up or switch off the colour layers as they wish.

Do ME and EIM have preferred standards in that regard?

Neil A15/01/2019 22:20:08
101 forum posts

My own preference would be for option 1. It is what I am used to.

When I produced CAD drawings at work, like Duncan, I used various coloured lines on a black screen, but they were always printed out with black ink on white paper. Also the outlines were drawn 0.7mm with the other lines and dimensions at 0.5mm. Of course, this was on A0, A1 and A2 sized sheets, you would probably need to make a scaled adjustment when working on A3 or A4.

As regards to using colour on the printed drawing, personally, I find that some colours are not that easy to read. Julius de Waal produces some very nice drawings, he uses rendered pictures, isometric views with some colour, in addition to conventional 2D views, to illustrate his models. Drawings like his I have no problem with, I quite like his style, although he does put more parts on each sheet than I would.

At the end of the day it is all about clearly defining what is intended to be made and hoping that you have not been ambiguous on some feature or missed out some dimensions. It can be difficult to check your own work. It is all too easy to know what you meant to be made, but have you actually shown it?


John McNamara16/01/2019 02:17:36
1314 forum posts
113 photos

Hi Jason

I issue quite a lot of building not engineering plans in A2 size for tendering.

I normally post them in the cloud at mediafire and issue a link for tenderers to download from.
I use black and white and shaded greyscale in preference to colour because the contractors get them printed in black and white even if they contain colour, Its cheaper!

And yes it makes little sense when you consider the value of the work they are quoting on.


Paul Lousick16/01/2019 05:38:27
1854 forum posts
661 photos

40 years as a design draftsman and like Neil A, produced 2D CAD drawings on a black screen and used colour for different layers then printed in black and white using different line weights for outlines, centre lines, hidden linese, etc. Many of the drawings were printed on A0, A1, A2 and A3. The main reason being the cost of large format colour printers. Some A4 and A3 size prints which had 3D images were printed in colour.

Some coloured lines on drawing prints are hard to read (yellow on white background for example but yellow lines on a black computer screan is easy to see)

Coloured images do not always copy very well if done on a B&W printer. The diferent shades of grey produced are not easy to see and the whole image lacks detail.

I use colour when producing 3D models and print as I did for 2D CAD. Black lines on white paper for drawings and sometimes colour for 3D images when printing at A4 and A3.


Edited By Paul Lousick on 16/01/2019 05:39:58

JasonB16/01/2019 09:09:59
21435 forum posts
2448 photos
1 articles


Thanks for the many replies, I won't respond to you individually but will make these comments:

It looks like No1 is the popular choice with No2 a close second. No1 is as I said what I have used in the past so that looks like it is the way to carry on with the 2D drawings. However I think as part of the package I will do a few sheets with coloured general arrangement and some sub assemblies possibly sectioned too that can be viewed on the screen to get a feel for how things go together much like this which I have just quickly put together. May also do a fancy rendered one too which I did start on a while back. There will also be my usual 100plus build photos available.

allman drawings 5.jpg

The small isometric will stay as I think that helps visualize the part particularly on my own engine designs that have been aimed at the beginner, this particular one is for a set of castings by Alyn Foundry and I don't see many beginners making that and maybe only two others makers if no more castings are forthcoming.

I do have an A3 printer but have sized all the drawings to A4 and scaled the parts to suit as that is what the majority of people will be using to print out their set on.

They will be in PFD format as that again does not need anything special to open, view or print and the files are a reasonable size. i'm approachable to anyone who may want a part in a different format for CNC etc, don't think there is a lot in this one that would lend itself to that but some of my Series 24 from barstock designs would.

Line widths have come up in a few replies, The images posted here are just screen shots and then resized by the forum software so don't really show what the actual print looks like. main solid lines are 0.25, dimension 0.13 and hidden detail 0.13 grey scale which are standard ISO pen nib sizes so will reproduce to standard sizes if the drawing is blown up to any other A size sheet. I will change that solid "Detail A" ring to a broken line as that was bugging me too. Below is a screen shot of the PDF ( again some clarity lost) or a direct link to download for those interested here

allman drawings 6.jpg


Without getting too much into the BA -metric debate. For my own designs I am using metric throughout with the odd exception for something like BSP though I could spec that as a "G" thread wink 2 This particular engine has a lot of the cast parts that are imperial and the other ones in their range were predominantly that too so I have stuck with imperial stock and BA fixings where visible but anything out of sight is metric for example the 3 CSK holes are sized to suit socket CSK screws and on other parts I have used some metric fine where the castings have come out a bit tight for BSP for example m10 x 1 rather than 1/8" BSP.

Thank's again and keep any feedback coming.


Edited By JasonB on 16/01/2019 09:22:25

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