Since 7 May, Pan F Plus has been sold in 4×5 and 8×10 sheets, in packs of 25, at roughly $88 and $275. Before that it existed only in 35mm and 120. It joins HP5 Plus, FP4 Plus, Delta 100 and Ortho Plus in Ilford's sheet range.

Giles Branthwaite, Harman's sales and marketing director, said it is "possibly the single most requested product we have, so I'm delighted to say we have listened and we have finally been able to deliver this." Ilford calls Pan F Plus one of the oldest continuously manufactured black-and-white emulsions in the world. It has been coated without a break for decades and never, until this year, cut into a sheet.

At ISO 50 it is the finest-grained and sharpest film Ilford makes, and on 8×10 that fineness does different work than it does in 35mm. A 35mm negative printed to 16 × 20 inches is magnified roughly fourteen times, and grain is what sets the ceiling. An 8×10 negative contact printed is not magnified at all. What the resolution buys there is tonal separation and edge detail in a print made at the size of the negative.

The speed is what it costs. A view camera stopped to f/45 to carry a near foreground and a far distance is already four stops down from f/11, and focusing close adds more on top. Work one case through: a 300mm lens on 8×10, focused at life size, sits 600mm from the film. The extension factor is the square of the draw divided by the focal length — (600 ÷ 300)² = 4 — so the metered exposure is multiplied by four, which is two stops. A reading of one second becomes four.

Four seconds is also where reciprocity stops behaving. A film's response to light is proportional over the ordinary range of shutter speeds and falls away from proportional as exposures lengthen, so the metered time underexposes, and the shortfall grows as the time grows. Harman publishes the correction for this emulsion in its data sheet. Applying it is the difference between the fine grain arriving on the sheet and a thin negative arriving.

Twenty-five sheets of 8×10 at $275 works out at eleven dollars a sheet, before the film holder is loaded or the shutter is opened.

GP