The Ilford Ilfospeed Multigrade II Manual from 1982 (printed in England 82.62.1A.GB) gives useful history relating to Multigrade paper.
"The original concept is due to Rudolf Fischer, who patented the idea in 1912, before going on to invent colour development with colour couplers. But it was not until 1940, when Ilford launched Multigrade, that the world saw the first commercial realisation of such a product. The revolutionary new material was announced by Frank Forster Renwick in a paper delivered to the Royal Photgraphic Society in May of that year. In his summary, Renwick described Multigrade as having magic qualities in that it would cover almost all variations of the paper grades that had been in common use and would give an endless range of contrasts to suit all kinds of negatives."
The text page (below) illustrates Frank Forster Renwick, FCGI, FIC, Hon FRPS, who was born in 1877 and died in 1943. He worked for Ilford, Ltd (initially the Britannia Works Co Ltd) from 1898 to 1922, before spending 3 years with Dupont in the USA. He returned to the UK and became Ilford's Director of Research from 1925. At the time of his 1940 lecture he was Past-President of the Royal Photographic Society and Scientific Director for Ilford, Ltd. It is unfortunate that he didn't live to see the success that Multigrade eventually became.
Mr Renwick's paper was delivered
on Tuesday 21st May 1940 and was reported in the August edition
of the Photographic Journal. Further information appeared in
the April 1943 edition.
by F F Renwick, F.C.G.I., F.I.C., Hon. F.R.P.S.
A very crowded Meeting of the Society gathered at the Society's House to hear a lecture and see a demonstration of the Ilford Company's new printing paper - the Multigrade process - on Tuesday, May 21st, 1940
In introducing the lecture, The President, Mr F J Mortimer, who was in the chair, said that in the early days of The Royal Photographic Society it was a regular thing for the members to give accounts of new processes, but in more recent years new processes had been less in evidence and the demonstration and lectures had been mostly concerned with modifications of existing methods. That evening, however, they were to have the first demonstration of the new printing process called Multigrade. This was practically explained by its title. Many grades of bromide printing papers had been made to meet the requirements of modern negatives, and most manufacturers produced anything up to six grades of each kind of paper. Recently, however, that had been reduced to three, called 'soft', 'normal' and 'contrasty', which dealt with the variations in contrast of most modern negatives.
Messrs. Ilford had now come
along with an entirely new paper, which had almost magic qualities
in that it would cover almost all the variations of grades which
they had had, and would give an endless range of contrasts to
suit all kinds of negative.
Mr Renwick needed no introduction, for he was a Past President
of the Society, and as Scientific Director of Ilford was to introduce
and describe the subject, which would be followed by a practical
demonstration to be given by the staff of Ilford, Limited.
Mr. Renwick then read the following paper, illustrated by slides
of the apparatus used in conjunction with the new paper.
"In past years when I have appeared before this Society I have usually dealt with matters which are of interest to a small minority only of our members, and I am duly grateful for the courtesy which those among my audience who were merely bored invariably displayed on such occasions. To night, on the other hand, I feel that no apology is needed for bringing to your notice a new and somewhat revolutionary type of printing paper, and some simple accessories which have been specially designed to facilitate the making of prints upon it.
In the early autumn of 1936 I happened to be studying some tests of an experimental paper in which a sensitising dye was employed, and was rather puzzled by certain peculiarities in its behaviour, until it occurred to me as a possible explanation that part only of the emulsion was colour-sensitive and the rest merely blue sensitive. In order to test this idea I arranged to have made two emulsions of very different types, to colour sensitise only one of them and mix it with the other before coating. When this was done it was found that there was no difficulty in exposing and developing each component of the mixture separately if suitable colour filters were placed in front of the exposing light. In this way the idea for a new kind of development paper took shape in my mind, and our laboratory and factory staffs then proceeded to solve the many problems involved in manufacturing a new product possessing the special characteristics which our knowledge and experience suggested as desirable.
Such, briefly, is the history of Multigrade paper about which I propose to talk to you to night. I must, however, give due credit to a brilliant German chemist, R. Fischer, who in a patent taken out in 1912, which was evidently not followed up, first published the underlying idea, but without giving any working particulars, and who evidently pinned his faith to a method involving coating one emulsion on top of the other. We only discovered this patent several months after we had got to work upon the subject. [It was the same Fischer who discovered and patented about the same time the basic facts upon which are based all the recent applications of colour development.]
I should, however, add that there is more than one way of making a paper of the type to be described, and Ilford Limited, have felt it necessary to obtain patent protection for those methods which we have found to lead to the best results, as well as for certain accessory exposing devices. Multigrade paper is coated with an emulsion, part of which is not colour sensitised, while the remainder is sensitised to the blue-green region of the spectrum. That portion which is sensitised to blue-green light is of a very contrasty character, equalling in this quality the ultra contrasty grades of bromide paper, while the unsensitised portion is rather softer in gradation than a "soft" grade of bromide paper.
It would be equally easy to make a paper of the same kind with which blue light gives great contrast and yellow light gives soft results, but there are advantages for the alternative we chose. The best sensitising dyes for our purpose are naturally those possessing the special property of being so strongly held by the grains of the dyed emulsion that they will not wander and sensitise ......."
As recounted in this website's Ilford Chronology, the original Multigrade, as described in Mr Renwick's paper, was withdrawn by 1945 as it failed to provide the image quality of conventional papers. Multigrade was reintroduced in May 1953 and withdrawn again after about 10 years.
Multigrade finally 'came of age' in 1974 when, with the introduction of Ilfospeed Resin Coated (RC) Multigrade, it at last equalled the quality of single contrast grade papers.
