Russian Collectors Imperial

Hello, I need help with Russian imperial 1908-1917 issue.
Here is the thing, 3 & 5 kopecks are based on Liapin2009 perforated 14 1/4:14 3/4, but mine are perforated top/bottom 11 1/2 (liapin doesn't mention it) but I found info regarding unofficial perforation of 11 1/2 but only for 4 & 5 kopecks stamps. Btw, the 3 kopecks has no gum. So, all comments, suggestions or info regarding their catalog# are welcome. Thank you

Please, any opinion regarding my post above would be very helpful. Thanks

https://goscf.com/t/18859&whichpage=2#531788

Nice page iStamp. I do like these Russian Imperial stamps.
The only suggestion I can make is, these were also issued imperforate in 1917 (Scott #s119-135). Perhaps someone has taken some of these and re-perforated them at 11.5 perfs. To what purpose, I couldn't tell you, but I can't think of any other explanation.

Thank you Jamesw for your answer and basically I agree with you if it wasn't for two things:
A) how many of such stamps were sold in auctions or asked about in SCF? My guess is not many
B) this sentence from liapin2009: "1908-1912 printings were printed on horizontal "cells" paper; the later printings were on vertical "cells" paper" and the fact that my 3k has got the horizontal "cells" paper , unlike the 5k which is on vertical "cells" paper.

So now I've authentic 3k stamp 1908-1912 issue on horizon. cells paper with different perforation, but I know nothing more about; and a 5k stamp 1913-1917 issue on verti. cells paper with different perforation and possibility that could be forged :-)))

Hi everyone
Could you advice if the stamp has what's called "yellowish chalk network" that rossica mentions? I also added image under UV light, Thank you

Have you tried taking a pic of the 4kop. under UV to see the
difference with the 3 kop. stamp ?

I don't have 4K to compare with only 5K which doesn't show any shade of yellow of the chalk network, but found a 4K on the internet, but that could be tricky to compare with...

It would seem that the 3 kop. has the yellowish tinge (78Ca).

Thank you, it would be nice to have a (R) stamp :-)
Oh almost forgot, liapin2009 doesn't mention this at all (only Rossica), so do you have any suggestions where to further look? Thank you

I don't know;maybe you will have to look through auction house
past sales ect..Found this in an old e bay listing:
https://www.ebay.co.uk/itm/1908-17-....c100623.m-1









1908-17-Russia-Sc-78-Mi-68-Zag-99Va-SHEET-YELLOW-GRAY-VARNISH-LINES-1600$

Thank you a lot for your help Perf12

Perf12
Here's the 7kop with yellowish varnish lines variety according to Rossica.

Hello
Inverted groundwork is my key question: the 1kop stamp with black surch. is from the 2nd provisional issue 1919, but the 1kop original stamp is from the 11th issue
1889-1892 imperial eagle etc and I believe that it has got inverted groundwork, but I could be wrong. Btw, image# 3 & 4 are captured while applying UV light.
Thanks

The yellow varnish lines should be looked at with caution I think.
There seems to be shades of yellow,yellow-grey,& grey.
Your stamp is the 12th printing Horiz. laid paper.The 2 dots are in the
center of the Rhomboid.So I don't think it's inverted background.One of
the dot's may be missing,but I think that's due to the inking.
examples of inverted groundwork:
https://www.cherrystoneauctions.com...20&pagenum=1
and:Your stamp here......
https://goscf.com/t/49499

Perf12
The inverted groundwork on the 1kop stamp has got nothing to do with the rumble and the dots inside the rhombus ( this counts only for 4kop and 10kop), here the inverted groundwork is all about the crown! The original 1kop without the provisional surcharge is from the 11th issue and the stamp has horizontally laid paper and I quite doubt that the Russian 11th issue 1889-1892 has got any stamp with varnish lines. The gray lines you see is a watermark#4.