ValueError: month must be in 1..12

[malaterre]

What did you do?

I would like to have a reproducible date in the sRGB default profile generated by PIL.ImageCms module.

What did you expect to happen?

Date should be set to 1900-01-01

What actually happened?

Exception is thrown upon read-back.

What are your OS, Python and Pillow versions?

• OS: Linux
• Python: 3.13
• Pillow: 11.1.0

$ python3 -m PIL.report
--------------------------------------------------------------------
Pillow 11.1.0
Python 3.13.5 (main, Jul 15 2026, 20:25:40) [GCC 14.2.0]
--------------------------------------------------------------------
Python executable is /usr/bin/python3
System Python files loaded from /usr
--------------------------------------------------------------------
Python Pillow modules loaded from /usr/lib/python3/dist-packages/PIL
Binary Pillow modules loaded from /usr/lib/python3/dist-packages/PIL
--------------------------------------------------------------------
--- PIL CORE support ok, compiled for 11.1.0
--- TKINTER support ok, loaded 8.6
--- FREETYPE2 support ok, loaded 2.13.3
--- LITTLECMS2 support ok, loaded 2.16
--- WEBP support ok, loaded 1.5.0
--- JPEG support ok, compiled for libjpeg-turbo 2.1.5
--- OPENJPEG (JPEG2000) support ok, loaded 2.5.3
--- ZLIB (PNG/ZIP) support ok, loaded 1.3.1
--- LIBTIFF support ok, loaded 4.7.0
--- RAQM (Bidirectional Text) support ok, loaded 0.10.2
--- LIBIMAGEQUANT (Quantization method) support ok, loaded 2.18.0
--- XCB (X protocol) support ok
--------------------------------------------------------------------```

from PIL import ImageCms
import io
import struct

profile = bytearray(
    ImageCms.ImageCmsProfile(ImageCms.createProfile("sRGB")).tobytes()
)
target_date_bytes = struct.pack(">6H", 1901, 1, 1, 0, 0, 0)
profile[24:36] = target_date_bytes
icc_bytes = bytes(profile)

with open('test.icc', 'wb') as fw:
    fw.write(icc_bytes)

prof = ImageCms.ImageCmsProfile(io.BytesIO(icc_bytes))
cms = prof.profile
print(cms.creation_date)

Discussion on SO:

• https://stackoverflow.com/questions/79982191/default-creation-date-in-pil-imagecms

[radarhere]

I've created #9804

[malaterre]

@radarhere Do you want me to open a different bug for year=0 or can I just update this one ?

[radarhere]

Just leave another comment here with an explanation.

[malaterre]

As a user I'd like to be able to blank (wipe) the creation_date completely. The following script should not raise an exception:

$ cat test2.py
from PIL import ImageCms
import io
import struct

profile = bytearray(
    ImageCms.ImageCmsProfile(ImageCms.createProfile("sRGB")).tobytes()
)
target_date_bytes = struct.pack(">6H", 1, 0, 0, 0, 0, 0) # year = 1
profile[24:36] = target_date_bytes
profile[24:36] = bytes(12)
icc_bytes = bytes(profile)

with open('test.icc', 'wb') as fw:
    fw.write(icc_bytes)

prof = ImageCms.ImageCmsProfile(io.BytesIO(icc_bytes))
cms = prof.profile
print(cms.creation_date)

See the line: profile[24:36] = target_date_bytes where 'year=1' is acceptable.

In case you are on a linux system the following script should not trigger an exception:

from PIL import ImageCms
import io

with open('/usr/share/color/icc/ghostscript/srgb.icc', 'rb') as fw:
    icc_bytes = fw.read()
    prof = ImageCms.ImageCmsProfile(io.BytesIO(icc_bytes))
    cms = prof.profile
    print(cms.creation_date)

I suspect this is a convention to set all u16 fields to zero for an empty date ...

[radarhere]

The problem is that cms.creation_date is attempting to return a Python datetime.datetime object, and if you look at https://docs.python.org/3/library/datetime.html#datetime.datetime and https://docs.python.org/3/library/datetime.html#datetime.MINYEAR, it will become apparent that Python has 1 as the year minimum.

So it looks like Python itself disagrees with your plan. Pillow could return the creation date in a format other than a datetime.datetime object, but I'm not convinced that this edge case justifies modifying the API.

[malaterre]

Makes complete sense. Thanks