One here - https://en.wikipedia.org/wiki/File:Shell_18pdr_HE.jpg
Had a discussion regarding the yellow of 112lb aerial bombs last weekend with someone making replicas, personally i'm of the opinion that on something designed to be instantly disposable, there would no doubt have been quite a variety of shades used within reason
Went digging - I'll have to dig out the official scheme but a couple of posts on the 14-18 forum turned up the following:
From user "TonyE" posted 01 July 2008
"The colour codes were:
HE - Yellow Chemical - Light Grey Incendiary - Red Smoke - Light Green Shrapnel - Black Shrapnel Reduced Charge - white from shoulder to driving band Some early 13 and 18pdr. shrapnel were painted slate colour but this was discontinued.
In addition to the basic colour there were the various coloured rings to indicate everything from "Filled" to the type of gas in chemical shells."
and from user "Sommewalker" posted 19 September 2012
"Well the paint scheme does vary somewhat according to the calibre of the shell, but generally HE shell is buff (dirty-white) overall. The 18 pdr then has a half-inch ring painted around the body about two inches down from the fuze. This may be a hatched ring depending on whether the ammunition is suitable for desert and tropical conditions. Below this about the centre is a green band about 1.5 inches deep, denoting amatol filled, with figures denoting the % of ammonium nitrate and trotyl stencilled beneath: typically 80/20. There is additional stencilling denoting the presence of a gaine fitted inside the shell, or not and the place and date of filling. 4.5 inch howitzer shell is similar but the stencilling includes the calibre and mark number. There were variations in the overall paint such as green for smoke shell (although this may be post-War) and grey for chemical. Star shell was usually black and incendiary red and buff. Common shell was black with a white tip and a red band. There were many variations within these schemes. The paint was not very durable under the handling it received in the field and is not often discernable in contemporary photos."
Certainly concede that the yellow colour of the projectiles in the model is reasonable - I raised it as a talking point.
It seems that an article on the colour of shells would be a good addition to Landships II - any volunteers?
