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16-bit grayscale TIFF is opened as 8-bit RGB


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Your TIF file has no EXIF information, and thus no color profile information embedded in it. That means that Affinity Photo has no way to know it's grayscale, and therefore it assigns a standard RGB profile to it.

-- Walt
Designer, Photo, and Publisher V1 and V2 at latest retail and beta releases
PC:
    Desktop:  Windows 11 Pro, version 23H2, 64GB memory, AMD Ryzen 9 5900 12-Core @ 3.00 GHz, NVIDIA GeForce RTX 3090 

    Laptop:  Windows 11 Pro, version 23H2, 32GB memory, Intel Core i7-10750H @ 2.60GHz, Intel UHD Graphics Comet Lake GT2 and NVIDIA GeForce RTX 3070 Laptop GPU.
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1 hour ago, walt.farrell said:

Your TIF file has no EXIF information, and thus no color profile information embedded in it. That means that Affinity Photo has no way to know it's grayscale, and therefore it assigns a standard RGB profile to it.

The TIFF file actually contains ample EXIF information, it's the photometric model that is stopping Affinity Photo from recognising its format correctly.

@icetype, the software (or device) that produces the TIFFs you're working with sets the photometric interpretation to "white is zero". Most TIFFs are either "RGB" (full colour) or "black is zero" (bilevel/greyscale). I've changed the EXIF tag, imported the TIFF and inverted it—it's attached to this post. Could you open it and make sure it's correct? If so, I can give you a workaround for now, but I'll also log it with the developers. Hope that helps!

16bitGray copy.tif

Product Expert (Affinity Photo) & Product Expert Team Leader

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Dear Walt and James,

Thank you for the valuable information and inputs. I really wish there is a way to "tell" Affinity Photo that it is grayscale upon opening. I can manually change the color format after loading, but then the image has already lost the gray level resolution.

Photoshop, Image J and GIMP etc. can somehow correctly recognize it as 16-bit grayscale.

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3 minutes ago, icetype said:

Thank you for the valuable information and inputs. I really wish there is a way to "tell" Affinity Photo that it is grayscale upon opening. I can manually change the color format after loading, but then the image has already lost the gray level resolution.

There is a workaround by changing an EXIF tag, I posted an explanation above—it maintains the 16-bit format and correctly assigns a greyscale colour profile, so you don't lose any precision. If you can verify that my attached TIFF file opens as a 16-bit greyscale document (so it actually works for you) I can detail the instructions. This would enable you to use Affinity Photo in the interim before the issue is fixed.

Product Expert (Affinity Photo) & Product Expert Team Leader

@JamesR_Affinity for tutorial sneak peeks and more
Official Affinity Photo tutorials

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Dear James,

Yes, I could verify that the TIFF file you attached (16bitGray copy.tif) can be correctly opened as 16-bit grayscale in both Affinity Photo and Affinity Designer. Detailed instructions will be truly appreciated. 

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17 minutes ago, James Ritson said:

The TIFF file actually contains ample EXIF information, it's the photometric model that is stopping Affinity Photo from recognising its format correctly

Thanks, James. Interesting; according to IrfanView (or my interpretation of what it's telling me) there's no EXIF info, so I'll have to look at that again.

-- Walt
Designer, Photo, and Publisher V1 and V2 at latest retail and beta releases
PC:
    Desktop:  Windows 11 Pro, version 23H2, 64GB memory, AMD Ryzen 9 5900 12-Core @ 3.00 GHz, NVIDIA GeForce RTX 3090 

    Laptop:  Windows 11 Pro, version 23H2, 32GB memory, Intel Core i7-10750H @ 2.60GHz, Intel UHD Graphics Comet Lake GT2 and NVIDIA GeForce RTX 3070 Laptop GPU.
iPad:  iPad Pro M1, 12.9": iPadOS 17.4.1, Apple Pencil 2, Magic Keyboard 
Mac:  2023 M2 MacBook Air 15", 16GB memory, macOS Sonoma 14.4.1

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16 minutes ago, walt.farrell said:

Thanks, James. Interesting; according to IrfanView (or my interpretation of what it's telling me) there's no EXIF info, so I'll have to look at that again.

Hmm, that's interesting—both Photo and exiftool can read the metadata...

@icetype, you can use any software that will modify EXIF data. I've used exiftool (https://www.sno.phy.queensu.ca/~phil/exiftool/install.html) but you could apply these instructions to other software.

You'll want to change the tag called "PhotometricInterpretation" to "BlackIsZero" or "1". To do this in exiftool, for example, you would type:

exiftool -PhotometricInterpretation="BlackIsZero" "path/to/file.tif"

Replace "path/to/file.tif" with your TIFF file (in both Windows and macOS I believe you can just click-drag the file onto the command prompt/terminal window)

Now load the file into Affinity Photo. It will assign a greyscale D50 profile and the bit depth should still be 16bpc. Now just go to Layer>Invert (since we reversed the photometric model) to see your image as intended.

Note that if you're using other software to modify the EXIF tags, it might be using friendly names—so you'd just look for Photometric Interpretation with a space rather than as one word.

Hope that helps!

Product Expert (Affinity Photo) & Product Expert Team Leader

@JamesR_Affinity for tutorial sneak peeks and more
Official Affinity Photo tutorials

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  • 3 years later...

I have the same problem with greycale TIFF 16 bit pictures.

So it is important for me to know, that Affinity can read and work with this format ... but:

Is there an easier way as modify EXIF data in terminal ?

Edited by xandr
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2 hours ago, xandr said:

Is there an easier way as modify EXIF data in terminal ?

Welcome to the Serif Affinity forums.

There are some "helpers" for ExifTool that provide a graphical user interface, but I've never used them and don't know which might run on Mac.

But it should be simple to create a script file on Mac that would run an ExifTool command against a specified file, and then make it available to use within Finder. A Mac user would have to give further advice on doing that (and one probably will :) ).

-- Walt
Designer, Photo, and Publisher V1 and V2 at latest retail and beta releases
PC:
    Desktop:  Windows 11 Pro, version 23H2, 64GB memory, AMD Ryzen 9 5900 12-Core @ 3.00 GHz, NVIDIA GeForce RTX 3090 

    Laptop:  Windows 11 Pro, version 23H2, 32GB memory, Intel Core i7-10750H @ 2.60GHz, Intel UHD Graphics Comet Lake GT2 and NVIDIA GeForce RTX 3070 Laptop GPU.
iPad:  iPad Pro M1, 12.9": iPadOS 17.4.1, Apple Pencil 2, Magic Keyboard 
Mac:  2023 M2 MacBook Air 15", 16GB memory, macOS Sonoma 14.4.1

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3 hours ago, xandr said:

Is there an easier way as modify EXIF data in terminal ?

There are many programs for editing metadata but I'm pretty sure that Exiftool is the most comprehensive. The commands can appear to be total gibberish but once you get the hang of them it is very quick and reliable. The only comment I would add to James Ritson's advice is for operating on multiple files rather than one at a time. If all of the files are in a single folder then, for Windows, I would open a command prompt there and do the following command

exiftool -overwrite_original -PhotometricInterpretation=BlackIsZero -ext tif .

Notes:
1. If you don't include  -overwrite_original then Exiftool will process the files and leave the originals unharmed as file.tif_original
2. The fullstop/period at the end of the command is not punctuation but means all of the files in this folder

MacOS installation is here https://exiftool.org/install.html#MacOS

Microsoft Windows 11 Home, Intel i7-1360P 2.20 GHz, 32 GB RAM, 1TB SSD, Intel Iris Xe
Affinity Photo - 24/05/20, Affinity Publisher - 06/12/20, KTM Superduke - 27/09/10

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