Uneven spark plug color

[Belmont]

I've been continuing to slowly go through the mechanicals of our new Minor. Last week I replaced ignition parts (plugs, leads, cap, rotor, points) and did a compression test. While doing this I noticed that the plugs had a very uneven color, after a 10 mile test drive. Plugs 1 & 2 look good, beige in color, while 3 & 4 are really black. The car runs well, but I have noticed a puff of smoke when I give it some throttle after sitting at idle for a short while. I do not know how much oil it burns as I've only done about 100 miles in it as of yet.

I will add some links for pictures of the plugs so you can take a look for yourselves:
https://postimg.cc/K1w0Yxj0
https://postimg.cc/YjMb0X2B

I mentioned that I did a compression test as well, here are the figure (hot engine, valve clearance at 0.015"):
Dry/Wet
Cyl 1: 155/165
Cyl 2: 165/180
Cyl 3: 170/175
Cyl 4: 175/180

These figures were actually alot higher than I expected since the engine is in unknown condition and was "stuck" sometime in the 80's according to the previous owner. Cylinder 1 is a bit lower that the others, what do you think of the figures?

I'm unsure about what is causing the uneven spark color, should I be worried/investigate further?

Thanks!

[oliver90owner]

Really black is not a good enough description.

Black, dry ‘sooty’?

Black , oily and a hard coating?

Two considerably different symptoms (or is it signs?).

Could be a few reasons for the difference, but more into required before guessing unnecessarily.

Most likely is oil going down the guides (blue smoke after idling).

[Belmont]

I think the pictures might be better than my description, but I would say more towards the "dry and sooty". I do not think that the (slightly?) lower compression on cylinder one has any connection to the other signs, just thought that compression could be useful info in this context.

[pgp001]

Looks shiny to me, so more likely to be oil than soot.

Phil

[Belmont]

Thanks for replying! I have no great experience in this matter so any input is appreciated!

I found a picture of the plug from cylinder # 4 as well. I think that looks even more oily:
https://postimg.cc/zb2p8DZX