Quale spazio colore viene utilizzato dalle foto del mio iPhone 8?

Mentre le mie vecchie foto mini iPad dicono che il loro spazio colore è sRGB, le mie nuove foto iPhone 8 mi dicono che il loro spazio colore è "65535" ("valore sconosciuto"). Alcune fonti affermano che questo valore significa "non calibrato", ma che le informazioni non sono di aiuto. Esiste una fonte migliore che mi dica il vero spazio cromatico delle foto? Voglio incorporarli in un file PDF e per questo specificare lo spazio colore corretto.

$ exif IMG_8995.JPG 
EXIF tags in 'IMG_8995.JPG' ('Motorola' byte order):
--------------------+----------------------------------------------------------
Tag                 |Value
--------------------+----------------------------------------------------------
Manufacturer        |Apple
Model               |iPhone 8
Orientation         |Top-left
X-Resolution        |72
Y-Resolution        |72
Resolution Unit     |Inch
Software            |11.3.1
Date and Time       |2018:05:12 07:58:51
YCbCr Positioning   |Centered
Compression         |JPEG compression
X-Resolution        |72
Y-Resolution        |72
Resolution Unit     |Inch
Exposure Time       |1/2404 sec.
F-Number            |f/1,8
Exposure Program    |Normal program
ISO Speed Ratings   |20
Exif Version        |Exif Version 2.21
Date and Time (Origi|2018:05:12 07:58:51
Date and Time (Digit|2018:05:12 07:58:51
Components Configura|Y Cb Cr -
Shutter Speed       |11,23 EV (1/2403 sec.)
Aperture            |1,70 EV (f/1,8)
Brightness          |10,62 EV (5394,70 cd/m^2)
Exposure Bias       |0,00 EV
Metering Mode       |Spot
Flash               |Flash did not fire, compulsory flash mode
Focal Length        |4,0 mm
Subject Area        |Within rectangle (width 753, height 756) around (x,y) = (3
Maker Note          |926 bytes undefined data
Sub-second Time (Ori|700
Sub-second Time (Dig|700
FlashPixVersion     |FlashPix Version 1.0
Color Space         |Internal error (unknown value 65535)
Pixel X Dimension   |4032
Pixel Y Dimension   |3024
Sensing Method      |One-chip color area sensor
Scene Type          |Directly photographed
Exposure Mode       |Auto exposure
White Balance       |Auto white balance
Focal Length in 35mm|28
Scene Capture Type  |Standard
North or South Latit|N
Latitude            |47, 43, 40,97
East or West Longitu|E
Longitude           |13, 12, 25,38
Altitude Reference  |Sea level
Altitude            |989,768
GPS Time (Atomic Clo|05:58:51,00
Speed Unit          |K
Speed of GPS Receive|0,03549
GPS Image Direction |T
GPS Image Direction |221,05
Reference for Bearin|T
Bearing of Destinati|221,05
GPS Date            |2018:05:12
--------------------+----------------------------------------------------------
EXIF data contains a thumbnail (9560 bytes).

[AGGIORNAMENTO] Ora, usando exiftool(come suggerito da mattdm):

$ exiftool IMG_8995.JPG
ExifTool Version Number         : 10.60
File Name                       : IMG_8995.JPG
Directory                       : .
File Size                       : 3.8 MB
File Modification Date/Time     : 2018:05:12 17:54:37+02:00
File Access Date/Time           : 2018:05:17 21:55:15+02:00
File Inode Change Date/Time     : 2018:05:12 17:54:37+02:00
File Permissions                : rw-r--r--
File Type                       : JPEG
File Type Extension             : jpg
MIME Type                       : image/jpeg
Exif Byte Order                 : Big-endian (Motorola, MM)
Make                            : Apple
Camera Model Name               : iPhone 8
Orientation                     : Horizontal (normal)
X Resolution                    : 72
Y Resolution                    : 72
Resolution Unit                 : inches
Software                        : 11.3.1
Modify Date                     : 2018:05:12 07:58:51
Y Cb Cr Positioning             : Centered
Exposure Time                   : 1/2404
F Number                        : 1.8
Exposure Program                : Program AE
ISO                             : 20
Exif Version                    : 0221
Date/Time Original              : 2018:05:12 07:58:51
Create Date                     : 2018:05:12 07:58:51
Components Configuration        : Y, Cb, Cr, -
Shutter Speed Value             : 1/2404
Aperture Value                  : 1.8
Brightness Value                : 10.62069397
Exposure Compensation           : 0
Metering Mode                   : Spot
Flash                           : Off, Did not fire
Focal Length                    : 4.0 mm
Subject Area                    : 3194 1215 753 756
Run Time Flags                  : Valid
Run Time Value                  : 95831447299500
Run Time Scale                  : 1000000000
Run Time Epoch                  : 0
Acceleration Vector             : -0.9967756794 0.02542742023 -0.03952735125
Sub Sec Time Original           : 700
Sub Sec Time Digitized          : 700
Flashpix Version                : 0100
Color Space                     : Uncalibrated
Exif Image Width                : 4032
Exif Image Height               : 3024
Sensing Method                  : One-chip color area
Scene Type                      : Directly photographed
Exposure Mode                   : Auto
White Balance                   : Auto
Focal Length In 35mm Format     : 28 mm
Scene Capture Type              : Standard
Lens Info                       : 3.99mm f/1.8
Lens Make                       : Apple
Lens Model                      : iPhone 8 back camera 3.99mm f/1.8
GPS Latitude Ref                : North
GPS Longitude Ref               : East
GPS Altitude Ref                : Above Sea Level
GPS Time Stamp                  : 05:58:51
GPS Speed Ref                   : km/h
GPS Speed                       : 0.03548649749
GPS Img Direction Ref           : True North
GPS Img Direction               : 221.0531915
GPS Dest Bearing Ref            : True North
GPS Dest Bearing                : 221.0531915
GPS Date Stamp                  : 2018:05:12
GPS Horizontal Positioning Error: 4 m
Compression                     : JPEG (old-style)
Thumbnail Offset                : 2114
Thumbnail Length                : 9560
Profile CMM Type                : appl
Profile Version                 : 4.0.0
Profile Class                   : Display Device Profile
Color Space Data                : RGB
Profile Connection Space        : XYZ
Profile Date Time               : 2017:07:07 13:22:32
Profile File Signature          : acsp
Primary Platform                : Apple Computer Inc.
CMM Flags                       : Not Embedded, Independent
Device Manufacturer             : APPL
Device Model                    : 
Device Attributes               : Reflective, Glossy, Positive, Color
Rendering Intent                : Perceptual
Connection Space Illuminant     : 0.9642 1 0.82491
Profile Creator                 : appl
Profile ID                      : ca1a9582257f104d389913d5d1ea1582
Profile Description             : Display P3
Profile Copyright               : Copyright Apple Inc., 2017
Media White Point               : 0.95045 1 1.08905
Red Matrix Column               : 0.51512 0.2412 -0.00105
Green Matrix Column             : 0.29198 0.69225 0.04189
Blue Matrix Column              : 0.1571 0.06657 0.78407
Red Tone Reproduction Curve     : (Binary data 32 bytes, use -b option to extract)
Chromatic Adaptation            : 1.04788 0.02292 -0.0502 0.02959 0.99048 -0.01706 -0.00923 0.01508 0.75168
Blue Tone Reproduction Curve    : (Binary data 32 bytes, use -b option to extract)
Green Tone Reproduction Curve   : (Binary data 32 bytes, use -b option to extract)
Image Width                     : 4032
Image Height                    : 3024
Encoding Process                : Baseline DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:2:0 (2 2)
Aperture                        : 1.8
GPS Altitude                    : 989.7 m Above Sea Level
GPS Date/Time                   : 2018:05:12 05:58:51Z
GPS Latitude                    : 47 deg 43' 40.97" N
GPS Longitude                   : 13 deg 12' 25.38" E
GPS Position                    : 47 deg 43' 40.97" N, 13 deg 12' 25.38" E
Image Size                      : 4032x3024
Megapixels                      : 12.2
Run Time Since Power Up         : 1 days 2:37:11
Scale Factor To 35 mm Equivalent: 7.0
Shutter Speed                   : 1/2404
Create Date                     : 2018:05:12 07:58:51.700
Date/Time Original              : 2018:05:12 07:58:51.700
Thumbnail Image                 : (Binary data 9560 bytes, use -b option to extract)
Circle Of Confusion             : 0.004 mm
Field Of View                   : 65.5 deg
Focal Length                    : 4.0 mm (35 mm equivalent: 28.0 mm)
Hyperfocal Distance             : 2.07 m
Light Value                     : 15.2

Per qualsiasi motivo, il tag ColorSpace non è molto utile in EXIF. Gli unici valori standard sono 1 (sRGB) e 65535 ("non calibrato"). Tutti gli altri valori sono riservati. Alcune fotocamere li usano per indicare Adobe RGB o qualcos'altro, ma questo non è standard. Apple, infatti, sta usando Something Else e si trova altrove nei metadati. Con ExifTool, cercando i tag che iniziano con Profile, ho trovato:

Profile CMM Type                : Apple Computer Inc.
Profile Version                 : 4.0.0
Profile Class                   : Display Device Profile
Profile Connection Space        : XYZ
Profile Date Time               : 2017:07:07 13:22:32
Profile File Signature          : acsp
Profile Creator                 : Apple Computer Inc.
Profile ID                      : ca1a9582257f104d389913d5d1ea1582
Profile Description             : Display P3
Profile Copyright               : Copyright Apple Inc., 2017

che ci porta alla documentazione di Apple Core Graphics che dice:

displayP3

Il nome dello spazio colore Display P3, creato da Apple Inc. Questo spazio colore utilizza i primari DCI P3, un punto bianco D65 e la stessa curva gamma dello spazio colore sRGB.

Puoi leggere ulteriori informazioni sullo spazio colore DCI-P3 su Wikipedia .

tutti gli attuali display e software Apple di produzione che utilizzano lo spazio colore DCI-P3 (DCI / P3). riferimento wiki