>>> Problems of periodisation 2: >>> screen geometries

100-583 HISTROY AND PHILOSOPHY OF MEDIA 2010

A hundred and fifty years ago, two inventions revolutionised the image: lithography and photog-raphy. Combined in contemporary photolitho presses , large-scale printing of photographs lead us into a new set of mathematised techniques. Refined through fax, TV and digital transmission, our imaging technologies are dominated by grids. Is the unacknowledged presence of tiny squares just a random blip in a chaotic cosmos, or perhaps a structural characteristic of the society we now inhabit: the database economy.

Richard Parkes Bonington (1802-1828) Tour du gros horloge, Évreux Lithograph, 331mm x 245mm(detail of clockface above)

William Henry Fox Talbot, Latticed Window at Lacock Abbey, 1835

Stephen H. Horgan, Steinway Hall, New York Daily Graphic, December 2, 1873: first prited halftone photograph.

Bell Labs Wirephoto, first commercial transmission, New York 1935

The Quatermass Experiment, BBC TV, 1953, dir Rudolph Cartier, scr Nigel Kneale

Cathode Ray Tube

Trinitron Mask

LCD sub-pixel

H.261 CodecSTRUCTURE ‘a hierarchical structure with four primary layers. From top to bottom the layers are: Picture; Group of Blocks, or slice, or video picture segment; Macrob-lock; Block’ (ITU 2005:13

COLOUR YCbCr, which codes for luminance (Y) and two chro-ma channels (C), blue and red, on the principle that the panchromatic Y channel captures the necessary detail, while the absence of green (as used in almost all colour film, television and high-end storage media like DVD and Blu-Ray) minimises redundancy be-cause the green channel overlaps with both red and blue, especially in the yellow segment of the spec-trum. This is a variant of 8-bit colour graphics, which allows a range of 256 colours

KEYFRAMESuncompressed frames which are used as a reference for filling in compressed frames that come between them. In Flash vector animation, a similar process is

used to do the ‘in-betweening’, extrapolating from first and last frames the action needed to move from one to the other. This information is encoded not as full-frame animation but as an instruction set, which requires far fewer lines of code. As the Flash Video white paper notes, ‘A lower keyframe rate (such as one keyframe every six seconds) will result in a softer or blurrier image but reduces the band-width demand’ (Macromedia 2004: 13).

VECTOR PREDICTIONVectors predict movement based on sequence from an initial image. Encoding artefacts are increasingly likely in hand-held sequences when the prediction system is more likely to predict wrongly or as the Flash Video white paper has it, ‘If your camera is not steady, most of the image moves, causing a high per-centage of pixels in the video to change from frame to frame. A steady camera reduces the number of pixels that change from frame to frame, giving you better quality at higher compression rates (lower data rates’ (Macromedia 2004: 11).

ISSUES

1. UNIT ENUMERATION = commodity equivalence, exchangability2 AVERAGING = biopolitical management of probabilty3. PREDICTIVE SCANNING = protocological control => DATABASE ECONOMY

Ivan Sutherland demonstrating Sketchpad, 1963

Methodological PrinciplesConsideration - of the actually existing situation in its unique complexity

Wonder - at the specific unexpected details, readiness to question previous habits and assumptions

Hope - for a ‘difference that makes a difference at some later time’ (Bateson);