HP2 emulsion was first coated onto glass plates in 1937. Roll and 35mm versions appeared in 1938 and cut film (sheet film; flat film) appeared in 1940. Emulsion speed at first introduction was 100 ASA (ISO), equivalent to 200 ASA (ISO) after the 1960 speed re-rating. Note, however, (below) that Ilford were marketing cut film as 125 ASA (ISO) by 1941. Whether this fractional speed increase was just to give a marketing emphasis to the new HP2 emulsion or whether HP2 was rated upwards from its original 100 ASA to 125 ASA over the first years of its availability, is unsure.

In 1940, HP2 cut (sheet) film replaced Ilford Hypersensitive Panchromatic sheet film. In the description of the film in the “New Goods” section in the British Journal Photographic Almanac for 1941 it was said the film was 2½ times faster in speed than the previous “Hypersensitive Panchromatic” sheet film (though this claim conflicts with Ilford's own information). The box of 6½ x 8½ inches (whole plate) sheet film shown below, dates from 1941 and is in packaging originally intended for the earlier version of Hypersensitive Panchromatic rated at 31 Scheiner, approximately 100 ASA (ISO). Ilford applied a sticker across the original label to show that it contained films with the HP2 emulsion, now rated at 32 Scheiner, corresponding to approximately 125 ISO/ASA.

According to an instruction sheet for the films found inside the box, development times in ID-2 developer were 4 minutes for “Dish” development and 8 minutes for “Tank” development at 65°F. ID-2 was a medium grain fast working developer.

If finer grain was required the film could be developed in ID-11 Fine Grain developer for 10 minutes for normal contrast or 15 minutes for greater contrast, both at 65°F. These times were for “Tank” development and could be reduced slightly for “Dish” development. Ilford ID-11 developer was the equivalent of Kodak D-76.

Below is shown an advertisement from the rear cover of an “Amateur Photographer” magazine, dated 7th December 1938, for the (then) new 35mm Selo HP2 35mm film with a speed of 31 Scheiner, or approximately 100 ISO/ASA. Press photographer, Lancelot Vining, tests the new film in an indoor venue without flash with difficult lighting at an exposure of 1/50th of a second at f2.

The previous 35mm and roll film, “Selo Hypersensitive Panchromatic”, was rated at 30 Scheiner, or about 80 ISO/ASA.

Roll and 35mm film versions first appeared in 1941 and were initially slower at 125 ASA (equivalent to 250ASA in the post-1960 speed rating system).
Cut Film (sheet film; flat film) appeared in 1943, also initially at 125ASA. See the Ilford Speed Group 'F' designation rather than the 'G' of plates lower down.
Plates first appeared in 1942 and were immediately at the 'usual' HP3 speed of 200 ASA = Ilford Speed Group G (400ASA/ISO in the post-1960 speed rating system).
All HP3 emulsions became 200ASA (equivalent to 400ASA post-1960) around 1955 (maybe 1954).

This image sent to me by Jim Fisk of the Great Yarmouth Photographic Society (see the bottom of this web page) and friend of Paul Godfrey. He says "It came from the Charlie Read collection".

The expiry date of these 35mm films for darkroom loading into (especially) Leica cassettes was July 1948. The packaging lacks the Paddle Steamer trademark, which was 'dropped' in 1945, so it seems this pack was made around 1946, meaning it was one of the last packs of film refills made with the 'Selo H.P.3' name. Shortly after 1946 the name 'Selo' seems to have been dropped by Ilford and the film became just H.P.3. In another couple of years it was named simply HP3, i.e. no stops between the letters.

The original instruction booklet for the Ilford Exposure Meter Model B (on its page 8) shows that, even at the time the booklet was produced (March 1938), the Ilford Speed Group range had already increased to include the letter 'F', necessitated by "the recent increase in speeds of Ilford Hypersensitive Panchromatic Plates and Films". This presumably refers to H.P.2 becoming available in the 35mm format in 1938.

Image below courtesy of Michael Talbert
This box of HP3 Matt sheet film was manufactured pre-1955, as the Weston speed is given as 125 Weston (=ASA=ISO). Ilford increased the speed of all HP3 film emulsions to 200 Weston in 1955 to bring the speed in line with HP3 plates. As with HPS, experienced photographers could expose HP3 at 400 ASA (ISO) when developing in most of the Ilford film developers, ID-48 being the exception, with Microphen giving a slightly higher speed increase to 650 ASA (ISO).

This box contained HP3 Matt film, which had a matt finish on the non-emulsion side, giving the processed negatives a soft, flat appearance, although the contrast was not altered by the matt finish. The purpose of the matt finish was to give a surface for re-touching of the negative in pencil or dye, as might be required for portrait negatives. It was much easier to re-touch in pencil onto a matt surface which would otherwise have been glossy. HP3 films and plates were widely used for portrait photography in the 1950s and 1960s.

The pictures below are of boxes of HPS 120 size roll film, with the backing paper marked for 8, 12 or 16 'exposures'; 'poses' (French); 'aufnahmen' (German). The three films were sent to me by Jean François Bonnin. Although all three film boxes arrived unopened, I have carefully opened one (as can be seen) to enable the accompanying leaflet to be scanned. The film appears to have been packaged in late 1965 or early 1966. It has an expiry date of June 1968. The post-1960 film speed (no exposure safety factor) is shown as 800ASA (ISO).

The green/blue colour of two of the side panels of the film box proved difficult to duplicate by direct digital phtography so I have manipulated their colour in the pictures below, to try to match the original.

Image below courtesy of Michael Talbert
Box of HPS Sheet Film (Flat Film, Cut Film) dating from 1956 onwards. HPS sheet film was introduced in 1953, a year after HPS Plates (and a year before HPS Roll and 35mm Film), making it the fastest Sheet Film in the world at that time at 400 Weston (=ASA=ISO; note that this speed equivalence was only true after introduction of the Weston Master III exposure meter in 1956). The 400 speed rating included a “Safety Factor” of one stop, and experienced photographers processing their own films could safely expose HPS at 800 ASA (ISO) when using the Ilford developers ID-2 or ID-11, but not ID-48. ID-48 was an “Extra Fine Grain” developer, and its extra fine grain development decreased the emulsion speed by half a stop. A further gain in speed was possible by developing the film in Ilford Microphen developer when the film speed could be increased to 1,200ASA (ISO). Some photographers found they could expose at even higher speeds with extended development times in Microphen depending on the amount of shadow detail required.

The HPS box dates from pre-1957, because it is labelled “Ilford Limited London”. After 1956 this became “Ilford Limited Essex”.

Distribution of HPS sheet film had ceased by 1968. Roll film and 35mm HPS film production ceased by 1969. It was still possible to find out-dated boxes of HPS sheet film offered for sale at surplus photographic material dealers, such as A.W. Young, Marston and Heard, plus others, in the late 1970s.