Special 'stamp' for the philatelic press
Every postal service considers it important that as many new stamps as possible are purchased by collectors. To achieve this, the philatelic press is provided with color photographs of the upcoming stamps. However, series are also provided to journalists for this purpose. It sometimes happens that these uncancelled stamps are used, usually indirectly, to frank mail, and this is not the intention of that postal service.
That is why new stamps for the philatelic press are sometimes provided with a kind of postmark. An impression in the form of a simple circle. This renders the stamp 'unusable' for postage. The advantage is that the circle hardly distorts the image on the stamp. The disadvantage is that the stamp is not actually postmarked. Or is it not a disadvantage?
Do you also have such 'press stamps' in your collection?
As an example, I have taken a few issues from Hungary from the year 2000. Are these stamps with a small circle collectible? Or are they inferior? Or are they a curiosity? Keep them or… ??? 
Nice! I wasn't familiar with this variant. Collectible? As always, it depends on what you want. To me, they don't seem to belong in an official used collection, but I have a number from the German "famous women" series with pattern overprint (same principle, I believe), and I keep those in my unused collection without any guilt, just like so many specimen stamps. You can give them all a place within the broad spectrum of a stamp collection.
Cees, I think it doesn't matter to thematic collectors; after all, it's about the image on the stamps. And these cancellations aren't distracting at all. As long as it's a real stamp, no problem.
Quick question Cees, can you classify these stamps under the CTO designation?
I also have a number of stamps and blocks with these cancellations from Hungary and Finland. They are simply part of my collection.
I also have many stamps from Cyprus with specimen overprints from the years 1990-2000. I acquired these via 'Mijn Stokpaardje'. These stamps appeared as images alongside the new items and were therefore actually used for the purpose for which they were made/overprinted!
Toon, CTO, or Cancelled to Order, is a stamp impression made on request. Usually requested by a collector at the counter to cancel stamps (for his or her collection). I think it is better to refer to this as an 'official cancellation'. I don't really have a good name for it. Does anyone perhaps know a better term?
I don't think 'official cancellation' is such a bad idea. You could also call it a 'fraud prevention cancellation' or a press cancellation. I wasn't aware of its existence, though I was familiar with the press stamps with a line through a corner. Collectible? To me, yes, in my album of curiosities.
“Worth collecting? To me, yes, in my curiosities album”
Willem, you're press too, aren't you???
Why no press album then??? Rarities are something else entirely.....
@ Rein, you might be right, but because the press stamps only cover one page, I've moved them to the rarities. You have to make choices in life (as always).
Nice idea to start a collection of pressed stamps. I am not aware of such a collection. I would be happy to make the shown stamps and blocks from Hungary, plus a few extras, available free of charge to a serious collector who wishes to set up such a collection. Who is interested? Then I will get in touch.
In 2009 I wrote a blog about “sample stamps” see https://www.postzegelblog.nl/2009/06/22/voorbeeldzegels/#more-14417
And so you could also call these sample stamps press stamps. So yes Cees, I collect them 🙂
By now, I also have a seal with the inscription “specimen”. So it is growing steadily!
OK Willem, they are for you. I sometimes see what you've made of them at a club night in Leiden. I'm curious!
Thanks in advance, Cees, and I will do my best.