This shade came about as a result of the difficulty in obtaining suitable red inks for stamp production during the 1914-18 war. Prior to the war most inks were obtained from Germany, but as the war progressed these became unobtainable, which resulted in a number of unusual shades.*
The 1d Pink (SG16(16)) was first brought to the attention of the Post Office by one of their officers, F H Nichols who had purchased a book of stamps for his own use and found that the second and third panes were in an unusual pale pink shade. On 4 July (1916) Nichols reported this to his colleague W S Austin who immediately contacted Harrison's regarding the colour. Harrison's expressed surprise at the shade and promised to remedy the situation.
Later, in September, Harrison's colour merchants, JW and TA Smith, showed the Post Office further examples of these stamps as evidence of the problems they were having in trying to source suitable red inks and as supporting evidence of the need to import ?enemy produced? material, which was available from America or Switzerland, but could only be imported with a Board of Trade licence. Rather oddly, Harrison?s themselves had not used the difficulty in obtaining proper supplies of colour as an excuse when the matter was taken up with them by Austin, in July.
Although the initial Post Office enquiry related to stamps issued in booklets they also appeared in sheet form.
These stamps are normally found in unmounted mint condition having come from a complete sheet, since broken up; occasional mounted examples have been seen and used examples are not priced by Gibbons. Although the initial enquiry was made in 1916, pink stamps continued to appear until 1918, a K18 control block being known.
* For the full story about the printing ink problems, check out this article.