FR80 Image Sizes

Introduction

The complete FR80 plotting area has coordinates 0 to 16383 in both directions. Each camera is capable of photographing only part of the plotting area - the aperture plate ensures that plotting outside its bounds is not recorded. However, if output is produced over the complete area allowed by the plate, the images on consecutive frames overlap. Consequentially, it is usual to restrict plotting to at least an area such that two consecutive frames abut.

Standard Images

For 16mm and 35mm cine film, the frame area defined in the British Standard is smaller than the abut image with a gap between consecutive frames. The cine image is defined so that on most projectors the outer edges of the image will not be seen. In general, this is preferable to having a blank border around the screen image. However, it may be essential for certain information to be seen. For this reason, a second British Standard image (called cine (projector) ) is defined which should be completely visible on all projectors. However, projectors do vary and plotting near the edge of the defined area may not be visible on some.

It is possible to use different coordinate systems on the FR80, comic and cine. the X-coordinate is measure along the film in comic mode and across the film in cine mode. the following table give the four standard images in both coordinate systems (where applicable). Abutment is calculated so that boundary lines superimpose.

The image size is chosen to prevent page overlap. As the aperture plate has rounded corners, the aperture figures given here have been measured across a diameter. A box with these dimensions will have the corners cut off. No figures are supplied for abutting on microfiche because frames cannot be abutted reliably. This is because the microfiche film is not sprocketed and so cannot be accurately registered.