re: 16 bits = 15 bits in Photoshop?
re: 16 bits = 15 bits in Photoshop?
- Subject: re: 16 bits = 15 bits in Photoshop?
- From: John MacDonald <email@hidden>
- Date: Thu, 14 Apr 2005 07:46:08 -0400
- Organization: Dodge Color, Inc.
Rich,
Thanks for straightening that out for me.
John
Message: 2
Date: Wed, 13 Apr 2005 12:44:17 -0700
From: Richard Wagner <email@hidden>
Subject: re: 16 bits = 15 bits in Photoshop?
To: email@hidden
Message-ID: <email@hidden>
Content-Type: text/plain; charset=US-ASCII; format=flowed
Not quite, John.
20 is one, not zero, and zero is the "darkest dark." For an n-bit
unsigned integer, 2^n gives the number of levels, and 0.. 2^n-1 gives
the range.
In an 8-bit unsigned integer, there are 28 = 256 levels: 0, 1, 2,
...255.
PS does not use a simple, unsigned, 16-bit word for high-bit data, or
the number of levels would be 216 = 65,536, with a range from
0..65,535.
If PS used an analogous representation for 8-bit data, there would be
27 = 128 levels.
--Rich Wagner
>> "0" is one of the values of a 16-bit file, so the brightest white would
>> only go to 2 to the power of 15.
>>
>> In other words, the values go like this:
>>
>> 1. 2 to the power of 0 darkidiest dark
>> 2. 2 to the power of 1
>> 3. 2 to the power of 2
>> 4. 2 to the power of 3
>> 5. 2 to the power of 4
>> 6. 2 to the power of 5
>> 7. 2 to the power of 6
>> 8. 2 to the power of 7
>> 9. 2 to the power of 8
>> 10. 2 to the power of 9
>> 11. 2 to the power of 10
>> 12. 2 to the power of 11
>> 13. 2 to the power of 12
>> 14. 2 to the power of 13
>> 15. 2 to the power of 14
>> 16. 2 to the power of 15 whitiest white
>>
>> See?
>>
>> John MacDonald
>> Dodge Color, Inc.
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden