Russian stamp designs, essays

I'm looking for any information regarding Russian stamp essays. I can rarely find any in catalogues, usually these are unadopted designs.
I'm curious as some essays by famous Russian stamp designer Anatoly Kalashnikov have turned up here. Anatoly Kalashnikov designed dosens of postage stamps and hundreds of envelope designs. If anyone knows anything (numbers of designs in existance, their rarity etc) please contact me.

CoA comparision of normal and Error stamp 5s

I scanned a picture of normal 5s with protective network to compare it with error stamp on the right. Protective network lacks on some of proofs but then proofs are imperforate. Notice the difference of shades - various shades and papers of various printings offer a chance for detailed study. Simplified, there are thick and thin paper.

New Estonian 5s CoA Error discovery

Important discovery has been made with Estonian Coat of Arms (first issued 1928) 5s value. Stamp has missing network. It has not been recorded before and after asking expert he said he has never seen it although he has found 20s and 40s value with network missing. I'm interested wether anyone has to add information to this.

Nice Russian error

This arrived today, picked up from the auction. It's Russian 1969 fairy tales set in a strip of five with a missing perforation at the right side. Such errors are seldom found and this one is listed in Zagorsky 2009 catalogue along with other variations of missing perforation for this issue. Some have argued the printing quality of Russia was poor but I dare to differ. Indeed misperfs, preprint folds and missing perfs are to be found on several issues throughout the Soviet era but not on all of them.

I have found errors to be very attractive since I took my first steps with philately. I have also spent a great many hours looking for varieties, plate flaws and not only on Russian stamps. While such major error easily caughts the eye many smaller flaws demand more patience.

Toivo