File:Captain W. H. S. Widdowson portrait (1920).jpg

Copy Lighting Unit: Kaiser RB 5055 HF (AC 230V, 50Hz; 4 x fluorescent lamps of 55W each; colour temperature: 5400 K) Camera sensor: Phase One IQ180 Camera body: Phase One 645 DF Lens: Schneider Kreuznach LS 80mm f/2.8 Capture software: Capture One DB 7.2.1 (64 bit).

Digitization notes: Captured in RAW and output as TIFF in Capture One. Capture was flat-fielded to correct for light falloff and lens distortion. No sharpening was applied at either the lens correction stage or in post-production. A Film Standard gamma curve was applied to the RAW image before output. A minority of items were shot under preservation-quality photographic glass due to lack of flatness. These were batched separately to allow for accurate colour correction. Colour accuracy was achieved by shooting an X-Rite Colour Checker Classic as a reference target at the start of each batch. White balance was set via the Neutral 8 square (the second-lightest grey patch, with RGB values of 200), and all conditions and settings were kept consistent to this reference shot for each batch. All RGB values in the Preservation Master are therefore accurate within the Adobe RGB (1998) colour space.