I hope the Scottish Tartans Authority doesn't mind, but I did a little reverse engineering for you:

Campbell ITI 1
B: #345064
G: #5c6428
K: #101010
B28 K6 B6 K6 B6 K32 G32 K6 G32 K32 B32 K6 B6

Black Watch ITI 207
B: #202060
G: #006818
K: #101010
B44 K4 B4 K4 B4 K32 G32 K4 G32 K32 B32 K4 B4

So, apart from the different shades of blue and green, the black "tramlines" on the Campbell are thicker than on the Black Watch. Note that this is only the STA's opinion on the matter. I assume both ITI 1 and ITI 207 are derived from actual woven samples, and woven samples can and have varied over the past, especially in a tartan as commonly used as the Government sett.

Here is the Campbell sett approved by MacCailein Mor, according to Alistair Campbell of Airds:

B24 K4 B4 K4 B4 K20 G24 K6 G24 K20 B22 K4 B4

Very similar, but here the black stripe on the green square is thicker than the black stripes on the blue squares.

Whether the textile weavers use any of these setts is another matter altogether. There is at least one major Scottish woollen mill that weaves the Campbell tartan so that the blue squares which contain the tramlines crossing in the center are smaller than the blue squares which contain the tramlines all crossing at the edges, and the blue squares which contain one pair of tramlines in the center crossed by two pairs of tramlines at the edges are all rectangular! I don't much care for it.