The erstwhile catalogue notice of “double-impressions” have been abandoned for the Old Period material. With handprinting it is not unexpected that bounce-strikes of varying exuberance have occured, and it should be difficult to say when a sufficiently non-exuberant bounce shouldn’t count. On the other hand, pairs of stamps printed notably skew with respect to one another (some seven examples now and counting) are finding increased recognition in the SG catalogue:
The new SG90a (as of the 2008 catalogue) shows two successive, mutually inverted, aligned, and proximate printings of the upper sector of the visitors’ plate, from which this curious (and none too adroit) excision was performed. These are positions #4 on the left and #2 on the right of the ¼a black watercolor. The other four pairings have not been reported so far as we are aware. Collection Hellrigl.
Enough said! Uncatalogued. Collection Hellrigl.
Stamps (positively) printed on both sides are sometimes noticed. There are currently two, the ½a black circular on European laid paper (SG41a) and the ½a black New Rectangular official on thin wove paper (O7a).
Here is another: A 1a dark blue-green, heavily inked, subject #3 in the plate, with a positive printing (mostly subject #2) on the other side. The properly-centered stamp shown on the left is faintly visible through the paper, mirror-reversed of course. The obliteration with its anomalously thick and widely-spaced bars is not exactly dedicated to inspiring confidence.
A rather vigorous offset (mirror-reversed) printing of a ½a ‘red’ (subject #13 in the plate). The three postal markings conspire to give us a likely Dec. 1882 dating. The pencil notation “stamp reversed” is that of Masson. We do not know what is on the other side of the stamp, if anything.
A catalogued “double impression” in the ¼a brown on thin wove paper. Another is catalogued for the 1a green under the same heading, and a third in the ¼a black official as a “double print.” We do not know if a difference of meaning is intended between a double impression and a double print. Our thanks to Sandeep Jaiswal for the scan of this very rare anomaly.
A ¼a connected to a partial impression from the 1a plate, inverted. This topic is dealt with in ► Séfi & Mortimer. It is important to realize that the examples shown in that work are reconstructions: the twinned stamps as shown in full by those authors were not actually present in their physical examples; the twinnings would have appeared to them as in the example above (which, by the way, happens to be a configuration not mentioned by those authors.)