I wanted to describe the factors that you need to look at in order to properly classify the printings and then combine them into an efficient algorithm that you can use to sort large quantities of Small Queens Quickly and efficiently.
The following attributes will almost always lead to positive identification if you know them well and understand what to look for:
4. Position dots
Because there are exceptions to the general rules established by each attribute above, it is often necessary to consider several attributes together.
Most of the first Ottawa printings of all values other than the 1c and 3c are perforated between 11.75 and 11.9. This is a gauge that is never found on the Montreals or the second Ottawas. Some of the 1c and 3c values are perforated 12 exactly, so in those cases, one needs to look at other attributes to identify them positively. Some of the 3c first Ottawa printings are found perf. 12.5 and again, this perforation only occurs on the first Ottawa printings, so it is a dead giveaway.
The perforations found on the Montreal printings are:
12 (1876 onwards)
11.5 x 12 (1873-1880)
11.75 x 12 (1876-1878)
12 x 12.25 or 12.25 x 12. (1887-1888)
John Hillson, a foremost expert on the Small Queens says that this last perforation only occurs on the Montreal printings and that all second Ottawa printings are perf 12. So if any of your stamps are one of the above four compound perforations, you have a Montreal printing. If your stamp is perf 12, then you must look at other attributes to make a final determination.
So to recap: look first for perf. 12.5, or 11.75-11.9. Those will automatically be first Ottawa and then look carefully at the papers in order to become comfortable with them. Then look for 11.5 x 12, 11.75 x 12 and 12.25 x 12 or 12 x 12.25. These are all Montreal.
Then place the perf 12's in a group to sort according to paper.
There are three papers that are exclusive to the first Ottawa period:
1. A very good quality horizontal wove with a clear grain that is silky to the touch. Not just smooth, but silky.
2. A thick fibrous wove, similar to Duckworth paper 8, as found on the Large Queens that was used at the end of 1871 for some printings of the 1c and 3c. This paper can be identified by the opacity, the fineness of the horizontal grain and the fact that there are either perf. discs attached still, or a large protrusion of fibres at the perforation tips.
3. A very white thin paper with a vertical grain was used in 1872. It is often found on the 2c value. Again, it is very smooth, being almost silky to the touch. While there were a lot of vertical wove papers used in the Montreal period, they are not as smooth, as thin or as white as this paper. Usually, a good amount of the design will show through the back of this paper.
The papers used on Montreal printings are generally stout horizontal or vertical wove, with a clear mesh. Late printings of the 1c and 2c values are found on newsprint like paper, with a lot of raw fibres being visible on the surface under magnification, so for these two denominations, one has to check the perforations as stamps perforated 12 all around will be Second Ottawa and those perf. 12 x 12.25 or 12.25 x 12 will be late Montreal.
On the second Ottawa printings for all values other than the 3c, the paper is generally a poor quality newsprint like paper. On the very poor quality paper prior to 1893, the paper looks almost unsurfaced,as one can see raw paper fibres clearly under magnification. There is some improvement in the quality in 1893, but the paper still has a toned, rough appearance compared to the paper on the Montreals. The 20c and 50c values used a soft wove with clear horizontal mesh. This is not an issue because the 20c and 50c are automatically second Ottawa, as they were not issued until 1893. The tricky stamp are certain printings of the 3c vermilion, which between 1895 and 1896 can be found on a smooth white wove with a very fine grain. This paper is quite unlike the poor quality newsprint and the stout papers used for the Montreal printings. Positive identification of these stamps can be made by looking at position dots, perforations and cancellations.
So for the perf 12 stamps that you have from the above sort, look for any value on newsprint like paper or poor quality toned paper. These will all be second Ottawa. Then for what is left, look for the thin, white vertical wove or thick soft fibrous paper. Set those aside as first Ottawa. You should be left at this point with white stout white papers of varying thickness with varying degrees of visible mesh. Place the values other than the 3c aside, as they will be Montreal printings. Set the 3c stamps aside for further review of potion dots, cancels and shades.
The first Ottawa printings of the 1c are always a deep orange or a bright red orange. Later orange shades always have a fair amount of yellow in them. But in these cases, the perforations should be the deciding factor. The 3c stamps from this period are never orange-red: they will either be copper red, Indian red, rose. The 2c and 6c values are more difficult to allocate, but generally the 2c greens are softer and contain more emerald than the later Montreals that are a richer green. The 6c stamps contain much less to no yellow undertone in the brown, compared to the Montreal printings which almost all contain some yellow in the brown.
The 2c stamps of the second Ottawa period are usually either dull yellowish green or strong blue green. The 3c stamps are usually a shade of vermilion, though those printed at the Montreal Gazette between 1888-1889 are either rose carmine or deep rose carmine. The 5c stamps contain no trace of green whatsoever. The 6c stamps are all shades of red-brown, chocolate or chestnut. The 10c stamps are all shades of reddish brown or pink - there is no purple, magenta or lilac in them.
For the 3c stamps put aside above, look at the shades. Any obvious vermilion (vermilion is a very deep orange red that is more red than orange) is second Ottawa. Any rose carmine is Montreal from the Gazette period. Place the remaining, less obvious shades aside for further analysis.
Now at this point look at the stamps you have identified as Montreal and check for misidentified stamps based on colour:
2c stamps that are clearly blue green or dull yellow green
5c stamps that do not contain green in the shade
6c stamps that are shades of red-brown, chocolate or chestnut
10c stamps that are more shades of pink or red brown.
Many stamps of the Small Queens can be found with one or two small dots in the bottom left corner of the stamp. These dots are generally only found on either the first Ottawa or Montreal printings. By 1880, the method of laying down the subjects in the plates changed, so that after 1880, the position dots are found hidden just outside the vignette oval at 3 o'clock or 9 o'clock. However, the stamps in the first vertical column of sheets had no dot. Thus one can find stamps with no dot that are actually first Ottawa or Montreal.
The A plate used for printings of the 6c value had two position dots in the lower left corner and by the second Ottawa period, there were up to four dots. So the use of position dots is not such a useful attribute for sorting the 6c, as a particular stamp could come from any period.
I would use this characteristic only to check those stamps that I have already identified, or to make a final determination where I am fairly sure that a stamp is either a Montreal or a second Ottawa and I want another factor to help make the final decision. But because there are so many possible exceptions to the general rules established for identifying printings with these dots, it is not a very useful attribute unless the value you are looking at has a dot, and is not a 6c, in which case you have a Montreal printing prior to 1880 or first Ottawa printing.
It will be useful to analyze the last of the 3c stamps that you have not identified in the above sort. Any with dots in the lower corner are Montreal. Then check the vignette ovals at 3 O'clock and 9 O'clock. If there are no dots then these are likely Montreal before 1880 from the first vertical column of the sheet. If dots are present then they could be either Montreal after 1880 or second Ottawa. To sort these, we need to look at cancellations.
Using dated cancels to identify printings is not 100% reliable for two reasons:
1. Occasionally the wrong date slugs were used in post office hammers, and
2. Stamps were used on a last-in-first-out basis, so when quantities ran low, new orders were often stacked on top of old remainders, so that it is possible to find earlier printings with late cancels, although it is not common.
Until April 1894 it was against postal regulations to cancel a stamp with a date stamp. Most dated copies prior to this date are those where the duplex canceler was incorrectly struck by the postal clerk. If you have a dated copy after April 1894, chances are it is a second Ottawa.
Again, I would only use dates to check the accuracy of what I had already sorted and to separate the last of the stamps that I couldn't identify with certainty. So for the last of the 3c stamps in the above sort I would look at the dates. Those prior to 1889 must be Montreal and those afterward are most likely second Ottawa.
The only values during the first Ottawa period are the 1c, 2c, 3c, and 6c, Any others cannot be first Ottawa.
The 8c, 20c and 50c were not issued until 1893, so these must be second Ottawa.
The gum of the perf. 11.5 x 12 Montreal printings is generally dull and streaky. For the remainder of the period, the gum is shiny and a light cream colour. Second Ottawa gum is usually dark yellow or brownish yellow. There was a lot of regumming on this issue, so examining gum to identify printings is not the best characteristic to use unless you know the gum well. However, if you come across a perf. 11.5 x 12 stamp with thick shiny gum, chances are it has been regummed.
Bringing it All Together Into the Most Efficient Way to Sort
Step One: start with the denominations
As stated above 8c, 20c and 50c are second Ottawa
10c, 5c and 1/2c are either Montreal or second Ottawa
1c, 2c, 3c, and 6c are either first Ottawa, Montreal or second Ottawa
Step Two: look at the shades on the 1c, 2c, 3c 5c, 6c and 10c
1c stamps in orange red or deep orange are first Ottawa.
2c dull yellow greens or clear blue greens are second Ottawa. Confirm by checking the perf to make sure it is 12 all around. Others are either first Ottawa or Montreal.
3c vermilion shades are second Ottawa. Rose carmines are all Montreal. Any rose, Indian-red or copper red shades are first Ottawa.
5c with any hint of green in the shade is Montreal. others are all second Ottawa.
6c with any hint of red to the brown are second Ottawa. Others are either first Ottawa or Montreal. 6c with hints of yellow in the brown are all Montreal.
10c with no hint of lilac or purple are second Ottawa.
Step Three: look at the papers on the 1/2c, 1c, 2c, 3c and 6c
Any newsprint or poor quality toned paper is automatically second Ottawa for anything other than the 1c and 2c.
Thick, fibrous opaque wove on the 1c and 3c is automatically first Ottawa.
Thin, white vertical wove on the 2c that is silky to the touch is first Ottawa.
Silky, smooth horizontal wove on the 1c, 2c, 3c, and 6c is first Ottawa.
The only values you should be unsure of at this point are some of the 1c, 2c and 3c stamps. to sort those proceed as follows:
Step Four: Check for position dots in the lower corner.
Any stamps with position dots in the lower corner will either be first Ottawa or Montreal prior to 1880.
Any without could be first Ottawa or Montreal before 1880 from the first vertical column of the sheet. Montreal after 1880 or second Ottawa.
Step five: Check the perforations
Perf 11.5 x 12 is automatically Montreal, as is 11.75 x 12 or 12.25 x 12 and 12 x 12.25.
Perf. 12 is either second Ottawa or it could be Montreal.
Any perf 11.75, or 11.9 is likely first Ottawa, but you shouldn't have any of these as looking at the shades should have eliminated them by now.
Step six: look at cancellation dates for the Perf 12's
Generally cork cancels will be Montreal. Most grid duplexes will be Montreal and dated CDS's after April 1894 are second Ottawa.
That should provide you with a reliable and efficient way to sort large quantities of Small Queens and Registered stamps easily. The registered stamps follow the same rules as the 2c and 3c stamps, except that there are no first Ottawas as these stamps did not appear until 1875.