Chalk-Surfaced Paper: Examples & Tips on Identification

I should perhaps qualify my use of the term "porous' in the quote above. You can think of normal unfinished paper as being just a pile of fibres all stuck together, with the fibres being visible under high magnification.  Here's an example I've posted before (thus I have the scan available to me):



The above is extreme magnification, 200x, but the fibres are easy to see.  Chalk-surfaced papers have a material laid over top of the paper - it's a surface of something runny which dries out and that is where my "porous" statement could cause problems.  You can often see tiny pinholes in the chalk surface - I assume there are small air bubbles mixed in with the chalk and if they pop as the surface is drying, they leave a little crater.  These craters could also be described as "porous", thus my poor choice of words.

There are some relatively common Hong Kong stamps (and other British Commonwealth stamps too) which are only available in chalk-surfaced printings - worldwide collectors could use these stamps to get an idea of how to tell the difference between the two types.  For example, in this King George VI set of definitives (authored by TSF member kgvistamps ) everything with a face value of 30c and under is on regular paper while most issues with a face value 50c and over are on chalk-surfaced paper (there are some which are also found on ordinary paper - 50c, each one of the 1946 dollar value issues).



Similarly, the first Hong Kong definitive set featuring Queen Elizabeth II (same basic design as above, just a Queen instead of a King) uses regular paper for the 5c, 10c & 15c issues, while all higher face values are printed on chalk-surfaced paper.

Papers were chalk-surfaced because that improved the printing quality.  Instead of having a rough ugly surface full of paper fibres, you could get nice clean printing on a nice smooth surface.  Sometimes you can determine whether a stamp is on normal or surfaced paper just by looking at how clean the printing is (again, high magnification is required, although 60x is probably enough to be certain).  I've also seen sites which recommend that you look for ink pooling up at the edges of printing, presumably the fibrous paper allows the ink to soak in somewhat as it dries whereas the ink is more likely to sit on the surface of the chalk.

The reason why you see these recommendations of testing for chalk surfaces by rubbing a silver wire is because you're doing a basic hardness test.  Plain unalloyed silver isn't very hard but it is harder than plain paper - it isn't harder than chalk-surfaced paper (think of the chalk surface as being baked like a ceramic).  So, when you rub on the hard surface with a soft wire, it's like writing with a pencil.  I think that's an awful idea, "let's see if we can scribble on the face of this stamp with a silver pencil, if we can it must be chalk-surfaced".  Use magnification instead!

Ryan

Thanks to all for their posts to add to the content of this thread: Ryan, stanley64, hrdoktorx, and angore

Vince, I did see your posts regarding the chalk-surfaced paper in the Ceres thread, so I am glad that you have put in a link back to that in this thread, too.

Al, thanks for your post, too.  Yes, I had picked up on Darrin's (darkormex) comment of chalk-surfaced versus surface-colored paper, and frankly, I wasn't really sure where he was going with that, as they are two completely different things to my understanding.  So, I thought we would start by focusing on the chalk-surfaced paper versus uncoated, and go from there.

My experience with surface-colored paper has not been good, as I ruined a couple of KGV Straits Settlements definitives that were apparently on surface-colored paper when I soaked them in water.  I was able to see the surface color get removed from the stamp just a moment after I put it into the water.  I was dismayed, to say the least.

I have had a similar experience with what I believe to be chalk-surfaced paper on some KEVII definitive stamps from Transvaal.  In that case, the color did not dissolve almost instantly like the surface-colored ones, but I could see it starting to dissolve, and I took the stamp out of the water and dried it immediately.  There was still some slight blurring and fading of the color, but at least I stopped before it was completely ruined.

As a question to you or anyone else who might know: will the ink on chalk-surfaced stamps or on surface-colored stamps always be fugitive in water?  Is that a given?

Ironically, the 1912 Nigeria set is not one where you have to identify chalk or ordinary paper to identify the stamps. The values from 1/2d to 2-1/2d were printed on ordinary paper, and the remaining values were printed on chalk paper. This is according to the Stanley Gibbons Catalogue. This is true for the King George V issues in general.

Where you do have to identify chalk paper on British Colony stamps are the King Edward VII stamps printed on paper watermarked MCA, and the King George VI issues.

I finally got a chance to scan the page from my Nigeria collection that I was referring to. Scott lists, like Steiner has laid out on this page, ordinary paper, chalky paper and surface-colored paper. I am going to try to re-identify the meager number of stamps that I have already mounted on these pages given the advice above (thank you everyone and especially, Beryllium Guy , for creating this thread).

It also sounds to me, based on what kgvistamps has said above, that the Scott listings and, hence, the Steiner pages are possibly in error (which is not surprising). Only the 3p, 4p, 1sh, 5sh and 10sh were printed, according to Scott, on surface-colored paper but it sounds to me based on what is being said above that this is the same as chalky paper and that this is a phantom identification created by Scott or am I misunderstanding what was said?




Here is my paltry collection of dupes for reference...These are basically of no help anyway because they were only printed on ordinary paper.



I have more on the way. I recently purchased a small lot on eBay that may fill in some of my blank spots, so perhaps there will be additional opportunities to figure out the differences.

So this question of Chalk paper vs Ordinary paper has been bugging me as well. 

I'm sorting out George the VI material from Leeward Islands and Bahamas and there are major price differences between the two papers.

I have several digital microscopes so I have done some scans as well as taken pictures on the microscope at 60x magnification. In this case the 2 stamps are obvious in the scans, but that is not always the case. When seen under magnification the smoothness of the Chalk paper is very obvious compared to the fibrous look of the ordinary paper. The sharpness of the engraving is greatly enhanced with the Chalk surfaced paper as can be seen from the microscope pictures.




This is a scan at 600DPI with Chalk paper first and Ordinary paper second.



1200DPI of chalk paper (SG 95a)



1200DPI Ordinary paper (SG 95)



Printed area of Chalk paper at 60x magnification.



Printed area of Ordinary paper at 60x magnification.