| Author: | Doug Emery |
|---|---|
| Date: | July 9, 2010 |
Contents
All core data files are prefixed with a two-part folio designation. There are 230 separate folio designations. The complete list of folios is detailed in the provided in the foliation document.
Sample folio designations are:
- 001r-004v
- 001v-004r
- 049v-052r
- 061r-0000
Each bifolium corresponds to a single under text folio. Each conjoin is expressed in over text folios numbers. The smaller of the two values is always first. No information about the orientation of the under text is suggested by the folio designation.
Each folio image in this data set is oriented based on the over-text orientation. In the example 001r-004v, the right portion of the page is folio 1 recto, and the right, folio 4 verso, as shown here:
------------------------- | 4v | 1r | | | | | | | | | | | | | | | | -------------------------
The reverse side of this conjoin is folios 1 verso and 4 recto, as shown here:
------------------------- | 1v | 4r | | | | | | | | | | | | | | | | -------------------------
In those cases where only half of the undertext page is available, the missing portion of the page is expressed by four '0' (zero) characters: '0000', as with '061r-0000'.
The remainder of the file name, including the extension, indicates the file type. Broadly, there are three types of file:
- TIFF image files, ending in 'tif',
- XMP metadata files, ending in 'xmp', and
- MD5 checksum files ending in'md5'.
The meaning of the remaining of the file name components depends on its type.
Each image file has a structured name that identifies the image content, imaging equipment type, and image capture or processing type. The basic structure is illustrated by the following file name.
- 016v-021r_A_pseudo_CFUB-0735.tif
Each segment of the filename is separated by underscore characters. The segments of the sample file are:
- troparia folios: '016v-021r'
- shot sequence letter: 'A'
- imaging and processing details: 'psuedo_CFUB-0375'
- processing tag: 'pseudo'
- illumination: 'CFUB-0375'
- extension: always 'tif'
In other words, the named file is an image of troparia folio 16 verso conjoined with 29 recto. It belongs to the shot sequence 'A' and is a pseudo-color image generated from the 'CFUB' and '0365' images.
Each of these segments is described below.
Value: A letter or group of letters, designating the group of images, the shot sequence, that the image, or the source image or images, this image belongs to.
'A' in the sample '016v-021r_A_pseudo_CFUB-0735.tif'.
The possible values are: 'A', 'B', 'C', 'D', 'E', 'EXP_A', 'EXP_B', 'EXP_C', 'EXP_D', and 'EXP_E'.
Each group of 23 registered images is assigned a shot sequence, like '016v-021r_A' or '016v-021r_B', composed of a folio designation and a shot sequence letter. The letters 'A', 'B', 'C', etc. indicate the order in which the images were taken. The first group of images taken of '016v-021r' is called shot sequence '016v-021r_A'. If a second set was taken, that second sequence would have been called '016v-021r_B'. A second set may be taken for any number of reasons, as, for example, an error in the first sequence, an adjustment to the position of the object, or an alternate aperture or exposure setting for one or more of the images in the group.
Two configurations of lights and settings were used with the course of imaging the palimpsest. Images taken using the second, experimental configuration have 'EXP' in the shot sequence.
The sample image, '016v-021r_A_pseudo_CFUB-0735.tif' was derived from the CFUB and 0365 images in the shot sequence '016v-021r_A'.
Note that the sequence letter, 'A', 'B', 'C' and so on, says nothing about the quality of the images in one sequence with respect to another. One sequence was selected for each folio as the best for that folio.
Value: One or more segments used to distinguish the image and ensure unique file names.
'psuedo_CFUB-0375' in the sample '016v-021r_A_pseudo_CFUB-0735.tif'
There are four types of images generated by special processing, using raw spectral images as sources. These are pack-8, pseudo-color, sharpie, and color-sharpie images.
Samples:
- 'pack8' in '016v-021r_A_0365_pack8.tif'
- 'csharpie' in '016v-021r_A_csharpie_CFUX-0735.tif'
- 'psuedo' in '016v-021r_A_pseudo_CFUB-0735.tif'
- 'sharpie' in '016v-021r_A_sharpie_CFUB-0735.tif'
- 'pca' in '080r-083v_A_pca_C1.tif'
- 'color' in 080r-083v_A_color.tif'
TODO - add color and PCB
In the processing position, these images have:
- pack8 - an 8-bit version of the 'raw' capture image
- pseudo - pseudo-color image
- sharpie - monochrome image derived from the pseudo-color image that 'strips away' the over text
- csharpie - "color sharpie" image; a color version of the monochrome sharpie that employs all three ultravoliet images taken with the color filter wheel
- pca - an image derived from a Principal Component Analysis, either a single component or an color image produced from three single component images
- color - a color image generated from five separate visible light images
Value: The illumination or illuminations used to produce the image.
- 'CFUB-0735' in the sample 016v-021r_A_pseudo_CFUB-0735.tif'
- '0365' in '016v-021r_A_0365_pack8.tif'
- 'CFUX-0735' in '016v-021r_A_csharpie_CFUX-0735.tif'
- 'CFUB-0735' in '016v-021r_A_sharpie_CFUB-0735.tif'
There are twenty-three illumination types, with one symbol each, and one symbol to indicate multiple illuminations. For pack-8, sharpie, color sharpie, and pseudo-color images, the illumination symbol will be one or a combination of the following symbols:
- 0365 - 365 nm LED illumination
- 0450 - 450 nm LED illumination
- 0470 - 470 nm LED illumination
- 0505 - 505 nm LED illumination
- 0535 - 535 nm LED illumination
- 0570 - 570 nm LED illumination
- 0615 - 615 nm LED illumination
- 0630 - 630 nm LED illumination
- 0700 - 700 nm LED illumination
- 0735 - 735 nm LED illumination
- 0780 - 780 nm LED illumination
- 0870 - 870 nm LED illumination
- 0940 - 940 nm LED illumination
- RAIR - raking infrared (940 nm) illumination from the right
- RABR - raking blue (470 nm) illumination from the right
- RAIL - raking infrared (940 nm) illumination from the left
- RABL - raking blue (470 nm) illumination the left
- CFUR - ultraviolet (365 nm) illumination with red color filter
- CFUG - ultraviolet (365 nm) illumination with green color filter
- CFUB - ultraviolet (365 nm) illumination with blue color filter
- CFBR - blue (450 nm) illumination with red color filter
- CFBG - blue (450 nm) illumination with green color filter
- CFBB - blue (450 nm) illumination with blue color filter
- CFUX - all three color filter ultraviolet images in combination (CFUR, CFUG, CFUB); used in color sharpie images
Processed pseudo-color, sharpie and color-sharpie images combine two or more images designated by a pair of illumination symbols. For example,
- 0365-0630
- CFUB-0735
- CFUX-0735
Except for the last of the symbols (CFUX), each illumination symbol corresponds to a raw image serial number. The PhotoShoot camera software that controls the camera and lights, captures all images in a shot sequence, like '016v-021r_A', in a regular order and appends a three-digit serial number to the resulting image '001', '002', '003', and so on, up to '023'. The captured images are Adobe Systems Digital Negative (TM) files, and have the exension '.dng'. For the sequence, '016v-021r_A', they are named thus:
- 016v-021r_A_001.dng
- 016v-021r_A_002.dng
- 016v-021r_A_003.dng
- ...
- 016v-021r_A_023.dng
The serial number-to-symbol correspondences are:
- 001 - 0365
- 002 - 0450
- 003 - 0470
- 004 - 0505
- 005 - 0535
- 006 - 0570
- 007 - 0615
- 008 - 0630
- 009 - 0700
- 010 - 0735
- 011 - 0780
- 012 - 0870
- 013 - 0940
- 014 - RAIR
- 015 - RABR
- 016 - RAIL
- 017 - RABL
- 018 - CFUR
- 019 - CFUG
- 020 - CFUB
- 021 - CFBR
- 022 - CFBG
- 023 - CFBB
The CFUX symbol is used in the color sharpie images, and designates the three ultraviolet color filter illuminations in combination: CFUR, CFUG, and CFUR. CFUX is always used in combination with another symbol, as in this example:
- 016v-021r_A_csharpie_CFUX-0735.tif
Note that illumination details including number of sources, wattage, spectral ranges, and their azimuthal angles are provided in the metadata.
Value: A flag describing the principal components used to generate the image
Sample:
- 'C1' in 144v-145r_A_pca_C1.tif
- 'C2' in 144v-145r_A_pca_C2.tif
- 'C5' in 144v-145r_A_pca_C5.tif
- 'rgb-1-2-5' in 144v-145r_A_pca_rgb-1-2-5.tif
- 'rgb-1-inv2-5' in 144v-145r_A_pca_rgb-1-inv2-5.tif
Flags of the form 'Cn', where 'n' is a single digit designate a single component from the PCA.
Flags of the form 'rgb-n-m-p' designate a color 'RGB' image generated from three principal components where 'n', 'm', 'p' are used in the red, green, and blue channels, respectively. This can be seen in '144v-145r_A_pca_rgb-1-2-5.tif'.
In some RGB images the data from one or more of the three components has been inverted. In these cases the inverted component is designated by a preceding 'inv', as in '144v-145r_A_pca_rgb-1-inv2-5.tif', where the data of component '2' in the green channel has been inverted.
There are two types of supporting files: XMP metadata 'sidecar' files and MD5 checksum files.
Each image file is accompanied by an Adobe Systems Extensible Metadata Platform (XMP) file and an MD5 checksum files. Each file type is documented in the external documentation directory of this archive. Each file has the same name as its parent file with either 'xmp' or 'md5' appended. For the file, 016v-021r_A_csharpie_CFUX-0735.tif these files will be named:
- 016v-021r_A_csharpie_CFUX-0735.tif.xmp, and
- 016v-021r_A_csharpie_CFUX-0735.tif.md5.