Finland Republic Helsinki Issue Watermark (Arms Type)

I soak this stamp in the water and lay it on a black surface and to my surprise the watermark showed clearly. It's a post horn so #208. On the scan is not very clear but the post horn can be seen in the middle of the stamp. This stamp is lightly cancel below the watermark so it can clearly been seen. There is many way to detect a watermark but when the stamp is heavily cancel it's a headache... Daniel

Off topic a bit but:

It may be just because I know what I'm looking for, but I find I can see many watermarks better if I soak the stamp in Ronsonol and then wait for it to dry.

KGB
The watermark is not clear on the scan. I used watermark fluid before but not Ronsonol. To my surprise this stamp in water and then dry showed a clear watermark, a post horn. It may depend on the kind of paper and/or the thickness. I collected Denmark before and on some pre-1900 stamps the watermark can be seen even without soaking. Not all watermark need Ronsonol to be seen. I'm no watermark expert but this forum teach me a lot. Watermarks have been discussed numerous times on this forum. Thanks for your post. Daniel

Pursuing the study of this stamp. I found out that on this Finland Scott #147 1928 stamp the postmark is inverted. Jay Smith sells it for $53 with the mention seldom offered. Paid the lot from Bulgaria $4.75. Yabadabadooo! Daniel

Here are the four possible post horn watermark orientations.



I think I see a watermark on your stamp but am not 100% sure of it's orientation. Which orientation do you believe this stamp has?
Don
APS #094826

Thanks! Top left.